Dew point: what is it, table, formula, calculation

Dew point - this is the temperature of the environment at which water in the air turns from gas into liquid (condenses).

Air humidity depends on its temperature. With the same amount of water vapor, cold air will be more humid than warm air.

If we gradually cool the air, then a temperature will come at which the humidity will become one hundred percent. At this moment, liquid condensation (dew) falls. This temperature is called the dew point.

The temperature and humidity of the air on the inner edge of the wall or roof of the house is much higher than on the street. This leads to that same gradual decrease in temperature inside the structure. If the insulation is not selected correctly, there is a possibility that inside the wall there will be such humidity and temperature at which condensation will form .

The nature of the appearance of dew

Water condensation on various surfaces occurs as follows.
Atmospheric air is always more or less saturated with water vapor. As the temperature drops, water changes from a gaseous state to a liquid state. This occurs when the surrounding air comes into contact with cooler surfaces and heat loss occurs. This leads to the formation of water droplets. Morning dew is easily explained by the laws of physics

The temperature at which water vapor from the air changes its state of aggregation to liquid is called the dew point.

The higher the content of water vapor in the air (or other gas mixture), the higher the condensation temperature of water, or dew point. For example, at 100% relative humidity, the dew point is exactly the same as the air temperature. Conversely, the lower the relative humidity, the lower the dew point. This means that for condensation to form, the air must be cooled more.

Thermal insulation material

As we have already figured out, it is better to use thermal insulation material that can be mounted on the outside of the building. As a rule, we are talking about penoplex, polystyrene foam or mineral wool.

The material based on mineral wool has good vapor permeability. In this case, part of the moisture is retained in the insulation and flows down under the influence of gravity. This circumstance does not threaten the insulation in any way, since basalt or glass fiber is resistant to moisture.

It would be a good idea to install a layer of waterproofing at the bottom of the building to prevent the foundation from collapsing.

Materials such as penoplex are vapor-tight, so when installing them you should leave an air pocket to remove moisture from the inner surface of the material.

If these conditions are met, we can talk about the safety of the walls and the effectiveness of insulation.

The dew point in a frame house corresponds to the place where liquid droplets form when cold and warm air currents come into contact. Heating the internal area of ​​a building involves heating the air, which is vented outside through the walls. Upon contact with a cold surface, the air temperature drops with the simultaneous formation of droplets. If condensation forms inside the insulation, its getting wet leads to premature loss of performance characteristics and the duration of operation of the building.

What is dew point

The dew point is the temperature at which condensation begins to form.
This term refers to the temperature at which air becomes saturated with water vapor to the limit. When cooled below the critical point, drops or fog form on objects.

This phenomenon is based on the fact that the maximum steam production of a cubic meter of air varies depending on its temperature.

Examples (data given in grams):

1. -5°C – 3.25.
2. 0°C – 4.85.
3. +10°C – 9.41.
4. +22°С – 19.44.
5. +28°С – 27.26.

The relative humidity value shows what the current set amount of water vapor is in relation to the maximum possible amount. For example, if this parameter is 34.5% at a temperature of +28°C, then the water vapor content in the air will be 27.26*0.345=9.4047 g/m3. From the above statement it follows that when the air is cooled to +10°C, the relative humidity will reach approximately 100%, i.e. this temperature is the dew point under given conditions. If the air cools further, too much water vapor is produced, some of which condenses.

Dew point temperature table

If you don’t have special equipment and don’t want to calculate using formulas, then there is a table. You can easily determine the dew point from the table.

Dew point determination table

Humidity percentage Temperature	40,00%	45,00%	50,00%	55,00%	60,00%	65,00%	70,00%	75,00%	80,00%	85,00%	90,00%	95,00%
-5°C	-15,3	-14,04	-12,9	-11,84	-10,83	-9,96	-9,11	-8,31	-7,62	-6,89	-6,24	-5,6
-4°C	-14,4	-13,1	-11,93	-10,84	-9,89	-8,99	-8,11	-7,34	-6,62	-5,89	-5,24	-4,6
-3°C	-13,42	-12,16	-10,98	-9,91	-8,95	-7,99	-7,16	-6,37	-5,62	-4,9	-4,24	-3,6
-2°C	-12,58	-11,22	-10,04	-8,98	-7,95	-7,04	-6,21	-5,4	-4,62	-3,9	-3,34	-2,6
-1°C	-11,61	-10,28	-9,1	-7,98	-7	-6,09	-5,21	-4,43	-3,66	-2,94	-2,34	-1,6
0°C	-10,65	-9,34	-8,16	-7,05	-6,06	-5,14	-4,26	-3,46	-2,7	-1,96	-1,34	-0,62
1°C	-9,85	-8,52	-7,32	-6,22	-5,21	-4,26	-3,4	-2,58	-1,82	-1,08	-0,41	0,31
2°C	-9,07	-7,72	-6,52	-5,39	-4,38	-3,44	-2,56	-1,74	-0,97	-0,24	0,52	1,29
3°C	-8,22	-6,88	-5,66	-4,53	-3,52	-2,57	-1,69	-0,88	-0,08	0,74	1,52	2,29
4°C	-7,45	-6,07	-4,84	-3,74	-2,7	-1,75	-0,87	-0,01	0,87	1,72	2,5	3,26
5°C	-6,66	-5,26	-4,03	-2,91	-1,87	-0,92	-0,01	0,94	1,83	2,68	3,49	4,26
6°C	-5,81	-4,45	-3,22	-2,08	-1,04	-0,08	0,94	1,89	2,8	3,68	4,48	5,25
7°C	-5,01	-3,64	-2,39	-1,25	-0,21	0,87	1,9	2,85	3,77	4,66	5,47	6,25
8°C	-4,21	-2,83	-1,56	-0,42	-0,72	1,82	2,86	3,85	4,77	5,64	6,46	7,24
9°C	-3,41	-2,02	-0,78	0,46	1,66	2,77	3,82	4,81	5,74	6,62	7,45	8,24
10°C	-2,62	-1,22	0,08	1,39	2,6	3,72	4,78	5,77	7,71	7,6	8,44	9,23
11°C	-1,83	-0,42	0,98	1,32	3,54	4,68	5,74	6,74	7,68	8,58	9,43	10,23
12°C	-1,04	0,44	1,9	3,25	4,48	5,63	6,7	7,71	8,65	9,56	10,42	11,22
13°C	-0,25	1,35	2,82	4,18	5,42	6,58	7,66	8,68	9,62	10,54	11,41	12,21
14°C	0,63	2,26	3,76	5,11	6,36	7,53	8,62	9,64	10,59	11,52	12,4	13,21
15°C	1,51	3,17	4,68	6,04	7,3	8,48	9,58	10,6	11,59	12,5	13,38	14,21
16°C	2,41	4,08	5,6	6,97	8,24	9,43	10,54	11,57	12,56	13,48	14,36	15,2
17°C	3,31	4,99	6,52	7,9	9,18	10,37	11,5	12,54	13,53	14,46	15,36	16,19
18°C	4,2	5,9	7,44	8,83	10,12	11,32	12,46	13,51	14,5	15,44	16,34	17,19
19°C	5,09	6,81	8,36	9,76	11,06	12,27	13,42	14,48	15,47	16,42	17,32	18,19
20°C	6	7,72	9,28	10,69	12	13,22	14,38	15,44	16,44	17,4	18,32	19,18
21°C	6,9	8,62	10,2	11,62	12,94	14,17	15,33	16,4	17,41	18,38	19,3	20,18
22°C	7,69	9,52	11,12	12,56	13,88	15,12	16,28	17,37	18,38	19,36	20,3	21,6
23°C	8,68	10,43	12,03	13,48	14,82	16,07	17,23	18,34	19,38	20,34	21,28	22,15
24°C	9,57	11,34	12,94	14,41	15,76	17,02	18,19	19,3	20,35	21,32	22,26	23,15
25°C	10,46	12,75	13,86	15,34	16,7	17,97	19,15	20,26	21,32	22,3	23,24	24,14
26°C	11,35	13,15	14,78	16,27	17,64	18,95	20,11	21,22	22,29	23,28	24,22	25,14
27°C	12,24	14,05	15,7	17,19	18,57	19,87	21,06	22,18	23,26	24,26	25,22	26,13
28°C	13,13	14,95	16,61	18,11	19,5	20,81	22,01	23,14	24,23	25,24	26,2	27,12
29°C	14,02	15,86	17,52	19,04	20,44	21,75	22,96	24,11	25,2	26,22	27,2	28,12
30°C	14,92	16,77	18,44	19,97	21,38	22,69	23,92	25,08	26,17	27,2	28,18	29,11
31°C	15,82	17,68	19,36	20,9	22,32	23,64	24,88	26,04	27,14	28,08	29,16	30,1
32°C	16,71	18,58	20,27	21,83	23,26	24,59	25,83	27	28,11	29,16	30,16	31,19
33°C	17,6	19,48	21,18	22,76	24,2	25,54	26,78	27,97	29,08	30,14	31,14	32,19
34°C	18,49	20,38	22,1	23,68	25,14	26,49	27,74	28,94	30,05	31,12	32,12	33,08
35°C	19,38	21,28	23,02	24,6	26,08	27,64	28,7	29,91	31,02	32,1	33,12	34,08

If you have any questions, leave them in the comments.

Scope of application of the concept

The transition of moisture into a liquid state significantly changes the living and working conditions of people and affects the functioning of structures and mechanisms. Therefore, in many areas, special attention must be paid to the location of vapor deposition.

Construction

The shell of most buildings is vapor permeable. The exception is metal workshops and garages. The relative humidity indoors is higher than outdoors, and water vapor penetrates the walls under partial pressure.

Buildings have vapor permeability, which depends on the type of building material.

If there are areas in their thickness with a saturation temperature or lower, condensation occurs, causing these effects:

1. Reduced thermal resistance of the structure.
2. Reducing the service life of building materials. When it gets colder, the water turns to ice and expands, causing internal damage.
3. Development of mold and fungal colonies (when the surface is wet).

Building materials have different vapor permeability. The lowest is in heavy reinforced concrete (buildings with floors) - 0.03 mg/m*h*Pa, the highest in aerated concrete blocks - 0.23 (at a density of 400 kg/cubic m).

Agriculture

When the air temperature drops, moisture condenses on the shoots and leaves of plants. If repeated frequently, this leads to disease. Thus, knowledge of the condensation point allows you to plan preventive and therapeutic measures.

Moisture condenses on the leaves of plants.

On the other hand, in arid regions, condensation of atmospheric moisture can partially replace the irrigation system. Breeders are working to develop varieties that can absorb water in this way. Knowing the critical point will then help determine the required irrigation capacity if the weather forecast does not predict rain in the near future.

Conservation measures for some plants, such as grapes, are also planned taking this parameter into account. If it is high, it means there is a lot of moisture in the air and frost damage, including radiation damage, will be moderate.

If the dew point is low, cover the shoots or water the area.

Physics of steam condensation

Water is present in the environment of our home in two states of aggregation:

• liquid – this is water for cooking and sanitary needs;
• gaseous - steam over boiling water or as one of the fractions of exhaled air.

In addition to such obvious places, traces of moisture are necessarily present in the materials of the elements of the building's building structure: concrete or brick walls, ceilings, and the base of the floor. There are no ideally dry building materials in nature. In stable warm weather, the steam present in the air and the moisture in the walls of the home are in thermal equilibrium.

In this case, the partial pressure of steam in the air from the street (outer side of the wall) and inside the house (inner side of the wall) is the same. This means that no movement of water vapor occurs through the wall. In frosty weather, the humidity of cold air is low, and the partial pressure of vapor in such air is low. In accordance with the laws of thermophysics, high-pressure steam (living space) begins to diffuse through the wall material to the cold street, where the pressure is lower.

All building materials from which the walls of houses are constructed have the property of vapor permeability. Even concrete or brick walls are capable of transmitting steam through their thickness, although concrete and brick have minimal vapor permeability.

When passing through the dew point in the wall, the steam turns into a liquid aggregate state, forming condensate moisture.

The appearance of moisture in the wall structure is accompanied by a number of negative factors:

• The thermal conductivity of a damp wall increases several times. This will mean that the heat exchange between the heated room and the street will intensify, and the house will always be cold.
• During the cold season, periodic freezing of condensate moisture in the wall occurs, followed by thawing. The cyclical nature of freezing has a destructive effect on the structure of the building material, reducing the period of trouble-free operation of the building.

It will be interesting:

Why do the corners in the house become damp?

Optimal indoor air humidity

How is air humidity measured?

How to get rid of humidity in the house?

The figure below schematically shows the transformation of vaporous moisture into a liquid state (blue color is used) when TR gets inside the wall of the home.

Moisture condensation when the TR is located inside the wall of the home

Where should the dew point be?

The ideal location for the dew point in a wall is the insulation on the outside of the wall. The thickness of the insulation on the wall should be such that during the coldest period of time, condensation does not flow into the wall itself, and if it does flow, it does not remain there for a long time.

Dew point isolated

The destructive effect of dew point in the body of a load-bearing wall can be seen in the following article.

Walls based on porous materials, such as foam blocks and sandwich blocks, brick and similar materials, require a higher layer of thermal insulation, since they absorb and accumulate moisture. Therefore, even a short-term (a few days) dew point in a porous wall can have a detrimental effect on the internal integrity. Thus, so-called warm masonry materials can only be effective in certain regions where winters are less frosty.

However, if it is predicted that the dew point will periodically move deeper into the wall of the house, or if this is likely, this fact should be taken into account when choosing masonry materials. In such cases, high-density masonry materials that can withstand several freeze-thaw cycles without damage are well suited. With a high frost resistance coefficient. Such frost-resistant materials include brick and foam concrete.

Frost resistance indices of the most commonly used wall materials

What to do to bring the dew point out of the house?

What is the right thing to do when the house has already been built and is in use, but the walls have begun to become damp? All of the above tells us that it is necessary to change the factors influencing the dew point. This means that you can either increase the heating to reduce the humidity level, or reduce the difference in the temperature of the coatings, namely, lay a layer of external thermal insulation.

Wall insulation options

Why do we insulate the walls from the outside? First of all, it's convenient. Secondly, in this case, the temperature of the external environment will be not the wall of the house, but the thermal insulation layer. The temperature decrease curve will become flatter, and the dew point will actually move towards the edge of the insulating layer. For important tips on this issue, watch this video:

The thicker the coating, the more likely it is that the dew point in the thermal insulation body will shift beyond the walls of the house. As a result, houses that are well insulated on the outside last longer and do not require high heating costs.

How to calculate the dew point in a wall with insulation

It is impossible to accurately calculate one place in the wall where condensation will form. Because the dew point depends on several parameters and is a variable value. You can only calculate a certain distance in the thickness of the wall where liquid will form under different temperature changes outside the house.

For example, if the indoor temperature is stable and the temperature outside becomes colder, the dew point will move along the thickness of the wall, closer to the room.

This formula can be used to calculate the dew point as accurately as possible for both homogeneous and multi-layer walls.

Calculating the dew point for any multi-layer wall is quite simple; the following data is required:

• Dew point at relative humidity in your area (table below)
• External temperature
• individual thickness of each wall layer
• internal temperature
• Thermal conductivity coefficient of the material from which the walls of the house are made

To determine in which part of the designed wall the dew point and condensation will be located, you need to know two values.

1. The dew point temperature in our region, as well as the humidity and temperature inside the building of interest to us. We can see this in the table above. Let's call this indicator Tp (dew point).2
2. The air temperature that will occur at the boundary of two layers of the wall at the values ​​​​of interest to us. Let's call this number Tc (the point between the layers).

If the difference between the above values ​​is positive, the dew point is inside the insulation, if the value is negative, the dew point will accumulate liquid inside the wall or house.

In other words, if the temperature at the interface between the insulation and the wall is higher with a positive sign than the dew point temperature from the table, condensation will form in the insulation.

Let's take the following conditions as an example:

The dew point temperature in a region with 60% humidity and a room temperature of 21ᵒC according to the table will be 12.9ᵒC. The air temperature at the interface between the thermal insulation and the wall is 15 ᵒC.

The difference between these values ​​is 15 ᵒC – 12.9 ᵒC = +2.1

If the difference between the above values ​​is positive, as in our case, the dew point is in the insulation, if the value is negative, the dew point will collect liquid inside the wall or house.

In our case, the temperature of liquid vapor release occurs before the saturated air reaches the main wall. And condensation will settle in the insulation, and not in the load-bearing wall of the house or inside the house.

This raises the question: if we take the dew point temperature at a given humidity level from a given table, how do we calculate the temperature between the layers of the wall?

The temperature at the boundary between two wall layers is relatively easy to calculate using the following formula:

Tc (temperature between wall layers) = (t2 – t1)x (S1x0.01/k) / (S1x0.01/k), where:

t2 – internal air temperature

t1 – external temperature

S1 – wall material thickness

k – thermal coefficient of the wall material

Simple example:

Let's take as an example a region where the dew point is 12.9 ᵒC in a region with 60% humidity, the indoor temperature is 21 ᵒC, and the outdoor temperature is 12 ᵒC below zero.

Now we need to calculate for these conditions what the temperature will be between a standard 38 cm thick one-and-a-half brick wall and a 10 cm thick external foam insulation. Subtract the dew point temperature from the table.

To do this, we will use the formula given above.

Tc (temperature between wall layers) = (t2 – t1)x (S1x0.01/k1) / (S2x0.01/k2)

According to the convention:

t2 = +21ᵒC (indoor air temperature)

t1 = -13 ᵒC (outside air temperature)

S1 = 38 cm (wall thickness)

K1 = 0.6 (thermal resistance coefficient of brick)

S2 = 10 cm (foam insulation thickness)

K2 = 0.04 (foam thermal resistance coefficient)

Calculation of the temperature between the brick wall and the foam insulation, under the climatic conditions we have chosen, will look like this:

( +21 – (-13ᵒC))x(38×0.01/0.6) / (10×0.01/0.04) = 9.52

According to our calculations, the temperature between a 10 cm thick foam core and a 38 cm thick brick wall, when the outside temperature is -13 degrees Celsius and the temperature inside the house is +21 degrees Celsius, is 9.52 degrees Celsius.

Therefore, if we subtract 12.9 degrees Celsius from the temperature between the insulation and the wall, which is 9.52 degrees Celsius, we get 9.52-12.9 = -3.38.

The calculated dew point is in the wall.

As you can see, the dew point is negative, i.e. the brick wall will reach a state of condensation and moisture will accumulate in it.

The above dew point calculation is more accurate with an error of up to 0.5 degrees Celsius, unlike some online calculators and other devices that do not take into account different material structures.

Options for insulating home walls

The TP parameter is a kind of temperature boundary at which internal heat and external cold meet. In wall enclosing structures, warm air that diffuses from a heated room into a frosty street during the cold winter months is supercooled.

The vapor phase of water turns into a wet state, depositing on any surface that has a temperature below TP. The cause of condensation is not only the material of the wall (wooden house, brick or aerated concrete), but also the method of arranging the thermal protection of the building, which determines in which direction the thermal expansion is displaced.

The location of the TR depends on the following factors:

• indoor and outdoor humidity indicators;
• indoor and outdoor air temperature indicators;
• thickness of the wall and insulating layer;
• places where insulating material is placed.

Depending on these factors, TP can be located not only on the surface of the wall, but also in the thickness of the wall or insulating material. Options for the location of the TR in the “wall plus insulation” system provide for the placement of the insulation inside the room or on the outside of the enclosing wall (see figure below).

TR for various insulation placement options

Wall without insulation

The location of the TR is within the thickness of the wall and can shift towards the street or room depending on changing temperature and humidity parameters.

In any case, whether the dew point is in aerated concrete or in a brick wall, condensation forms relatively far from the inner surface. Condensation moisture accumulates in the wall material and freezes in severe frosts. As temperatures warm, moisture thaws and evaporates out into the atmosphere.

There are three possible options for placing the TR in the wall:

• the TP indicator found by calculation or tabular method fell between the geometric center of the wall thickness and the outer surface - the inner wall remained dry;
• TP falls between the geometric center of the wall and the inner surface of the room - the walls of the room may get wet during a sharp cold snap;
• The TR exactly hit the coordinate of the inner surface - the wall will be damp all winter.

Heat loss with an uninsulated wall reaches 80%. The negative aspect of the occurrence of TR in a wall is the gradual destruction of the wall structure.

Walls made of brick, aerated concrete, expanded clay blocks, etc., which are homogeneous in their design, have a TR inside the thickness of the material in winter. Repeated freeze/thaw cycles worsen the strength properties of building materials and reduce the strength of the entire wall structure. Therefore, the walls of a monolithic structure of a homogeneous composition must be insulated with heat-insulating materials.

Insulation from the inside of the room

The following options are possible for the location of the TR:

• if the dew point is in the insulation, then the insulation will be wet throughout the frosty period;
• if the structure of the insulation material does not allow moisture condensation inside the insulating layer (expanded polystyrene, etc.), then condensation will fall out at the border of the inner wall and the insulating polystyrene board. The wall finish will begin to get wet, which will cause the formation of damp spots and mold;
• The wall material is located in the subzero temperature zone and is exposed to the negative effects of temperature changes.

Insulation from the outside of the building

TP is brought into the outer heat-insulating layer. The possibility of condensation forming in the room is excluded, the walls will be dry.

Dew point calculation online calculator

There are many programs on the Internet that can be used to calculate the approximate position of the dew point on the wall. The program calculates the dew point based on a number of criteria that must be entered manually. It includes information about the material from which the wall will be built, the number and thickness of layers of the wall, air temperature inside and outside the building and humidity. The online calculator is easy to use for calculations. Along with digital calculations, you can see charts and graphs of dew point movement depending on changes in air temperature. However, the calculation results of many calculators vary, and the accuracy of the calculations is unknown.

Online dew point calculator

Calculation of dew index

Correct calculation of the dew point in a specific area is important not only for determining the state of human health. It is necessary when carrying out construction and installation work, since the strength of materials, structures, and their ability to withstand corrosive destructive processes depends on the conditions for the formation of condensate.

Calculating the dew point is of great importance when choosing finishing materials for premises. The material can successfully withstand external moisture in the form of precipitation or simply exposure to water, but the formation of condensation inside it can have a quickly destructive effect.

Correct determination of dew point is important in aviation. Condensation formed at a certain flight altitude can lead to icing of the aircraft body with multiple negative consequences. Icing can especially hinder a successful flight during takeoff and landing, so treating the hull with anti-icing agents is an important part of preparing for a flight.

In forestry, the dew point is calculated when carrying out fire prevention measures. In agricultural work, determining the seasonal dew point is especially necessary during sowing. Through breeding methods, crop varieties are developed that are capable of forming condensate even in the absence of precipitation for a long time.

If you don't take into account the dew point

In the construction industry, ignoring the rules can lead to undesirable consequences. Metal, brick, concrete, wood and other materials will have a shorter lifespan. The formation of condensation in the area of ​​polymer-density materials when installed as thermal insulation is unacceptable and leads to the following problems

• Structures fail prematurely, leading to premature failure.
• The surface of the material swells;
• Condensation is necessary on surfaces with temperatures below the dew point;
• Large areas of finishing material peel off;
• Harmful fungi and mold develop on walls, causing illness;

Location of areas with high levels of condensation

The location of the dew point is determined by several parameters. The main factors are the humidity of air flows in the interior and heating temperature. Depending on the proximity of the point to the outer or inner cladding, the wall can be either dry or wet. The conditions under which the conversion of vapor to liquid occurs may vary. If +20°C is fixed in the rooms, the appearance of drops at a humidity of 60% will occur when the surface cools down to 12°C. At 100 percent humidity, drops will appear on walls heated to 20° above zero.

The location of condensation points is influenced by the following factors:

• An increase in wall thickness leads to an increase in thermal resistance. Access of cold air masses inside the building becomes difficult. In this case, the dew point moves deeper into the wall and can lead to premature wear of the insulation and expensive repairs.
• Insulation from the inside allows you to cut off the walls from the heat coming from the inside. In this case, drops of liquid appear in the immediate vicinity of the inner lining and also leads to premature destruction of the coating.
• External insulation is considered the best way to keep the walls of a frame house in perfect condition. The dew point remains near the outer wall, and moisture is gradually removed from the insulation without destroying it or causing rotting.

The farther the place where steam is converted into liquid is located from the inner wall, the more reliable and better quality the cottage or private house becomes. An external wall, if well insulated, shifts the place of condensation formation to the outside of the building and has a positive effect on the service life.

How to move the dew point in a wall

If, after performing all the calculations, you are not satisfied with the position of the dew point, you should consider moving it. This can be done as follows:

• improve the microclimate in the room - install forced ventilation, additionally heat the air.
• increase the insulation layer on the outside;
• remove the thermal insulation layer from the inside and move it to the outside;
• Use a material with high water vapor permeability;

The appropriate option should be chosen depending on the climatic conditions of the area, the design features of the house, financial capabilities and the building materials used.

Ignoring such a phenomenon as condensation in a wall “oven” can be very expensive. The minimum is an unpleasant smell in the room and constant dampness. The maximum is large colonies of mold, damaging the interior decoration of the walls, destroying the insulation and the health of the residents. Therefore, calculating the dew point is very important if you want to build reliable and dry walls in your home.

Why do windows cry?

There are specific recommendations for the microclimate in a residential area. This is humidity -40-50% and temperature +18-23C . Maintaining these parameters minimizes the possibility of condensation forming on the glass surface.

Its appearance is also associated with human life (it also releases moisture!). That is, there should be as many people in the room as sanitary standards allow.

High humidity can also be associated with improper air exchange. Here, too, there are standards: at least 3 “cubes” per “square” of area in one hour.

For kitchens, these requirements are even stricter: from 6 to 9 “cubes” per hour, depending on the type of stove ( 9 cubic m/hour for a gas stove ). Therefore, everything depends on the quality of ventilation.

There is a contradictory situation; The house was completely renovated, the old windows were replaced with double-glazed windows, and mold began to appear in the rooms. What is this connected with?

The fact is that during a complete reconstruction, the heating is changed, modern boilers are installed instead of old gas water heaters, and the windows are insulated. By and large, there are fewer opportunities for natural ventilation.

If previously moisture from the room could escape through loose window slits, through the hood of an old gas water heater, now there is no such possibility.

The operational characteristics of a double-glazed window (the “K” coefficient, in particular) are important, but secondary.

About the dew point in plastic windows

When it comes to the dew point for plastic windows, many people imagine a certain, secret place. In reality, as we have already seen, it is impossible to see the dew point. Let's repeat: the dew point is the temperature at which water vapor in the air becomes saturated and condenses after cooling to it. There are special tables that allow you to calculate the dew point for a certain relative humidity and a certain temperature. One such table is shown below.

Dew point for relative humidity

Note. Let's assume that the air humidity is 50% and the temperature is +21 degrees. Under these conditions, the dew point is +10.2. What does it mean? If the surface temperature in the apartment drops to +10.2 degrees, condensation will form on it. As a rule, the coldest surfaces in an apartment are plastic windows, so this is where excess moisture most often gets in.

People often encounter condensation on double-glazed windows. Based on what was said above, condensation can be dealt with in two ways - increasing the temperature of the windows and reducing the humidity in the apartment. A comfortable level of humidity can be achieved by ensuring normal air exchange. Any excess moisture - from laundry, a boiling pan, etc. – Any excess moisture – from washing, pots, etc. – must go away and not accumulate in the room. First of all, the apartment should be regularly ventilated. The frequency of ventilation is determined individually, but we recommend doing this for at least 10 minutes twice a day. Also, do not forget to use special ventilation valves.

Examples

Another simple example can be considered when something is brought into a warm room from the cold. The air above it cools, becomes saturated with water vapor, and water droplets condense on things.

Subsequently, the item warms up to the room temperature and the condensation evaporates. By the way, this phenomenon determines the recommendation not to immediately plug in household electrical appliances brought in from the cold.

Another, no less familiar example is fogging of glass in the house. Many people have windows that “cry” in winter; condensation falls on them. It is necessary to understand that this phenomenon is largely influenced by two factors - humidity and temperature.

Therefore, if you have a normal double-glazed window and proper insulation, but there is condensation, it means that not everything is in order with humidity; Possibly poor ventilation or exhaust.

One of the most interesting physical phenomena is a change in the state of aggregation of water, in particular the boiling of water. Read more detailed information in the article The boiling point of water is really very interesting. We are sure that you will find a lot of new things for yourself here.

You can read everything about breaststroke swimming in this article; it’s time to take care of your health right now!

Harmless dew point location

There are exceptions that, when a dew point occurs, do not harm walls, windows and other materials at all. If, for example, condensation forms on the outside of a wall on thermal insulation, this will not affect the internal structure and microclimate.

This is the most favorable position for the dew point, since in cold weather drops of moisture will not penetrate the wall. The dew point can also be located on the inside of the wall itself if it is close to the outside surface to keep the interior of the structure dry.

In all other cases, side effects may occur. To avoid such consequences, under no circumstances should you insulate walls from the inside. Such isolation will lead to the following consequences:

• Rotting walls from the inside. In very bad cases and at very high dew points, internal wall rot can occur. This leads to the destruction of the building material itself. As a result, the wall may simply collapse.
• Moisture will begin to accumulate at the boundary between the wall insulation and its covering. As a result, mold grows right inside the wall and cannot be eliminated.
• Drops of moisture will gradually move towards the thermal insulation. If condensation previously appeared only in the center, then it will gradually move towards the thermal insulation, forming fungal compounds.

To avoid this condition, you must check this value regularly. If dangerous values ​​occur, immediate action must be taken. However, you should know from the very beginning that thermal insulation has no place on the interior walls of the house.

Practical use

In practice, the meaning of the term dew point is important when insulating the walls of a building. To ensure optimal thermal insulation characteristics of the building envelope, it is necessary to know not only the value of the dew point, but also its position on the surface or in the body of the wall.

Modern construction methods allow 3 options for carrying out work, and in each case the point of condensation may be different:

A building constructed from a single material without additional thermal insulation. If the body of the wall consists of brick, stone or monolithic concrete, then if the construction technology in such buildings is followed, the dew point is located inside the wall. Its location gravitates towards the outer edge of the surface. As external temperatures decrease, the dew point will shift inside the wall. If the temperature difference turns out to be significant, there may come a time when the dew point is inside the room and moisture appears on the wall. We are all familiar with the situation: windows fogging up in winter.

With proper insulation from the outside, the dew point will be located inside the insulation

• The building was constructed with a layer of external thermal insulation. If calculated correctly, this thermal insulation is optimal. Correctly selected material thicknesses will allow you to insulate the structure, while the dew point will be located inside the insulation layer.
• A structure with an internal insulating layer. In this case, the dew point will be close to the inner surface of the wall, and in case of cold weather it will move directly to the surface.

An exception in the case of a wall of the same type would probably be wooden log houses. Wood is a natural material with excellent quality characteristics of low thermal conductivity and high vapor permeability. In such buildings, the dew point will always be located closer to the external surface. Wooden log houses almost never require additional thermal insulation.

The latter option is extremely undesirable and is done only when there is no other option. To learn how to properly insulate the walls of a house, watch this video:

Methods for determining dew point

You can easily measure the dew point yourself. There are several methods for calculating it. It is important to choose the one that is most convenient and practical. The main thing is to understand that after calculation you can only get an approximate value, since it is impossible to determine exact data for some indicators. Let's look at each method separately.

According to a special formula

This formula is one of the most accurate ways to determine dew point. The problem, however, is that you need to know the other values ​​in order to use them to calculate the final value. The formula looks like this:

A, b – constants (17.27; 237.7);

T – air temperature;

Rh – relative air humidity.

The error of this calculation is one of the smallest - it is only 0.5 degrees Celsius. However, it is necessary to know the temperature and relative humidity, which is not always possible.

Using special calculators

Currently, there are various online services with which you can easily calculate the dew point. In these special mini-programs, all fixed data and approximate values ​​are already entered, which are also necessary for more accurate calculations. All you have to do is enter the required values ​​and see the result.

The information entered usually includes the material from which the value is calculated and its thickness. However, this information must be entered for both internal and external parties. The program will then output a table with the following data:

• Minimum or maximum dew point.
• Moisture content in kg per cubic meter;

Based on this data, it will be easy to understand what condition the walls of the room are in and what needs to be applied. However, there is no guarantee that such calculators will provide accurate results, so caution should be used.

In addition, in some cases the following data is required:

• Average air temperature. The approximate outdoor and indoor temperatures should be indicated. These indicators also affect the final result of the calculation.
• Type of number. The humidity level, for example, in the bathroom should be very high, while in the living room it should not exceed 70%.
• Geographical position. The climate in different regions of the country is very different. Based on this, we can conclude that the normal dew point for the subjects is not the same. It should be borne in mind that somewhere outside the humidity level will be even higher.
• Layers of material. This line indicates what is behind the main supporting material. This is important because if there is no other room behind the wall, the dew point values ​​will be very different.

Advanced programs can even be downloaded onto devices. They have a much higher priority than traditional online calculators because they already use much more data to produce a result, which means the dew point will be determined more accurately. In addition, immediately after the final calculation, a special graph will appear on the screen, which is a schematic representation of the dew point in the wall.

When is it possible or not to insulate walls from the inside?

Now let's look at when it is possible to insulate a wall from the inside, when it is not, what it depends on and how it depends. What is this “no”, what are the consequences?

The main “is it possible or not” is what will happen to the wall after insulating it from the inside. If the wall is dry, it’s possible.

If the wall is dry, and only with a sharp, unexpected (which happens once every ten years) cold snap can it get wet, you can try to insulate it from the inside (at the discretion of the customer).

If the wall is consistently wet throughout the winter design period (with normal winter temperatures in the region), it cannot be insulated from the inside.

As we have already found out above, these consequences depend on the position of the dew point. And the position of the dew point in the wall can be calculated, and then it will be clear (BEFORE insulation) whether it is possible or not to insulate a particular wall from the inside.

Now a little discussion on the topic of what affects the possibility of insulation from the inside, and how it affects it.

This part of the article was prompted by questions from readers of the following nature: “Why can one person insulate from the inside, but I can’t, because he and I (further options) have the same apartment layout, or the houses are built from the same material, or the same city of residence, or the same wall thickness etc.

As we have already found out above, the consequences of internal insulation depend on:

• dew point (condensation temperature);

• the position of the dew point in the wall before and after insulation.

In turn, the dew point (temperature) depends on: room humidity and room temperature.

And the humidity in the room depends on:

• Mode of residence (permanently or temporarily).

• Ventilation (both supply and exhaust, are they sufficient according to calculations).

And the room temperature depends on:

• Heating quality.

• The degree of insulation of the remaining structures of the apartment building, except for the walls (ceiling, roof, windows, floor).

The position of the dew point depends on:

• thickness and material of all layers of the wall;

• indoor temperature. What it depends on was clarified above;

• temperature outside the room. It depends on whether it is outside or another room, as well as on the climate zone;

• indoor humidity. What it depends on was found out above;

• humidity outside the room. It depends on whether it is outside or another room (and on the mode of operation of this room), as well as on the climate zone.

Here is a list of these factors:

• mode of residence in the premises (permanently or temporarily);

• ventilation (both supply and exhaust, are they sufficient according to calculation);

• quality of indoor heating;

• the degree of insulation of the remaining structures of the apartment building, except for the walls (ceiling, roof, windows, floor);

• thickness and material of all layers of the wall;

• indoor temperature;

• indoor humidity;

• outside temperature;

• humidity outside the room;

• what is behind the wall, a street or another room (its mode of operation).

It becomes clear that there may not be two identical situations regarding insulation from the inside.

Let's see what (approximately, without specifics) the situation looks like when insulation from the inside is possible:

• permanent residence premises,

• ventilation is carried out according to the norm (for this room),

• The heating works well and is done according to standard,

• the remaining structures are insulated according to the standard,

• the wall that is planned to be insulated is thick and quite warm. According to the calculation of additional insulation for it, it should not be more than 50mm (foam plastic, cotton wool, EPS). In terms of heat transfer resistance, the wall “falls short” of the norm by 30% or less.

I think it is clear that in each specific case you need to consider your “input data” and then make a decision.

Everything that is written above gives the impression that there are very few cases when internal insulation is possible and not harmful. This is true.

In our experience, out of 100 who came up with the idea of ​​internal insulation, only 10 can do it without consequences. In other cases, it is necessary to insulate from the outside.

How to use the obtained result?

As you already understand, good thermal insulation is such thermal insulation (now we are talking about external thermal insulation of the facade) in which the dew point is in the middle of the thermal insulation. This parameter depends on many factors, for example, the thermal insulation properties of the insulating material decrease with increasing water content, i.e. A material with low water absorption should be used as an insulator.

How to calculate the required insulation thickness so that the dew point is inside the insulation? The properties of the insulation and walls are important here: the thicker the insulation, the faster the cold passes. From this we can conclude that a porous material will have better thermal insulation properties, and a wall made of dense concrete will require more insulation than a wall made of cinder blocks.

Vapor permeability of building materials

We present in the table below the vapor permeability coefficients of building materials

To ensure that the microclimate in the house is normal, when constructing wall “pies”, both the thickness of each layer and its water absorption and vapor permeability properties are taken into account. The layers of the cake should be arranged in such a way and have such thicknesses that vapor permeability increases from the inside to the outside. This “rule of vapor permeability” is best observed. Otherwise, there are two options:

1. Poor ventilation and high humidity in the house means that you can get the dew point in the wrong place, and as a result, dampness and mold and fungus on the walls, and possible destruction of the walls.
2. There is little humidity inside the house, and ventilation is organized - there will be no harmful consequences for the microclimate from violating the rule, except for the harmful effect of moisture on the wall material.

All this is true, the dew point must be taken into account, since it is a risk factor. But the degree of this risk depends on the real, actual amount of water condensed in the wall and on the properties of the wall material. The less water absorption a wall material has, that is, the less moisture it absorbs, the less it is at risk of destruction when this moisture freezes and expands in the pores. Brick Khrushchev buildings have been standing for more than 60 years, but they don’t even think about collapsing, although according to thermal engineering calculations they have condensation in the walls. Ceramic brick has good frost resistance characteristics; the frost ends and the brick releases moisture into the air. But we must remember that the walls of the Khrushchev buildings are half a meter thick.

Relationship between dew point and construction

The dew point value directly depends on the relative humidity and temperature outside and inside the building. For example, if the temperature outside is 8˚C, the temperature inside the house is 22˚C, and the relative humidity is 45%, condensation will form on the outside wall.

There are other factors that influence dew point, such as regional climate conditions, insulation of the entire building envelope, quality and type of heating system, length of occupancy (permanent or temporary, as in a house or garage), and ventilation.

It is very important for builders to know the dew point in order to accurately calculate the location of condensation on the walls and determine the required insulation thickness. Knowing this, you can minimize heat loss during the cold season.

The location of the dew point may vary depending on the thickness of the wall. It depends on the thickness and type of materials of the wall itself and insulation, the temperature and humidity of the air inside and outside the building.

Each material used for the construction and decoration of walls, with the exception of metal, has its own degree of water vapor permeability. From a physical point of view, this is an indicator of the amount of water vapor that a material can pass through itself in a certain time.

Vapor permeability is one of the decisive factors when choosing thermal insulation materials, and is also important when analyzing the condition of external walls.

During periods of low temperatures, water vapor under pressure in the room will tend to escape through all layers of the outer walls. The lower the vapor permeability coefficient of the insulation, the smaller the layer that needs to be laid. Its coefficient should increase from the inside to the outside, as does thermal conductivity.

If all calculations are performed correctly, the dew point will be in the thermal insulation layer of the wall, closer to the outer surface. In this case, the water vapor will turn into condensation and will only dampen the wall. This is how water vapor accumulates in winter, and in summer it is necessary to create conditions for the evaporation of accumulated moisture.

The main condition for good insulation is the creation of conditions for the evaporation of accumulated moisture. To do this, it is necessary to make special calculations and select finishing materials.

Less suitable is the location of the dew point in the load-bearing wall of the house. This occurs if the wrong type and thickness of insulation is selected.

In the worst case, condensation is on the inside of the wall. This situation is possible if the wall is not insulated at all or if the insulation is located indoors. In the latter case, mold may form under the insulation, and the wet insulation will not retain heat at all.

Defining the essence of the term

In simple terms, the dew point is the moment when the internal temperature of the room and humidity significantly exceed the surface temperature of the ceiling. In this case, moisture from the air inevitably condenses on the surface of the wall. This moment is influenced by:

• indoor air humidity;
• temperature of walls or ceilings;
• temperature inside the building.

If the room is humid and hot, then dew drops will immediately form on a cold glass.

Why is this term used in construction? Any fence: a wall or a window is a border with the outside world, which means the temperature of their surface differs from the average temperature in the room.

This means that moisture will regularly accumulate in the place where the dew point is located on the wall. Finding the dew point is influenced by:

• characteristics of materials used in construction and their thickness;
• installation location, number of layers and quality of insulation.

It is important that the dew point is on the outside of the building wall. Otherwise, we get a constantly wet surface and, as a result, the formation of mold, mildew, destruction of the decorative layer and the load-bearing characteristics of the structure.

Consequences of incorrect calculations

When choosing insulation materials, it is important to remember that one of the most effective ways to protect external walls from dampness is to properly install layers of insulation.

High-quality thermal insulation will help significantly reduce heat loss and make your home more comfortable, as well as extend the life of your walls.

A thick layer that does not allow water vapor to pass through and a porous layer that allows moisture to pass out should be located on the inside of the load-bearing wall.

It is also necessary to create conditions for ventilation in the condensation zone. This way, the condensate will evaporate freely.

A properly insulated exterior wall will help reduce heat loss during the heating season from 45 to 95% and create comfort in the house.

If the thermal insulation is chosen incorrectly, moisture will gradually accumulate in it, reducing the thermal resistance of the wall. Therefore, in the second or maximum in the fifth heating season, heating costs will increase, if we are talking about a private house, the apartment will simply be much colder in winter.

Professional insulation is a long and expensive process. Today there are many insulating materials. Do not try to save on them, as cheap materials will become unusable after just a few heating seasons.

There are several consequences of incorrect calculations, but some of them can have a negative impact on your quality of life. The main consequences are constantly damp walls, mildew, mold, mildew and germs on the walls, which lead to many chronic diseases.

Constantly damp walls become a breeding ground for fungi and mold, and their spores are transmitted by airborne droplets and cause diseases.

Because wet rooms are difficult to heat, their comfort levels are reduced. High humidity in such walls can cause respiratory diseases.

Another unpleasant consequence of a miscalculation is the destruction of finishing materials - tiles crumble, bricks on the outer wall crumble, and the surface of the inner wall begins to swell.

Undried condensation is the main reason that the outer wall is susceptible to weathering and peeling of finishing materials.

To remedy this situation, the condition of the walls and insulation must be analyzed by a professional. With the correct calculations, you can correct all mistakes and create a comfortable and warm environment in your home.

The principles and formulas of thermal engineering calculations for the correct design of a house will be discussed in the next article, which we strongly recommend that you read.

Is it necessary to insulate the bathhouse from the outside?

Whether or not to insulate a bathhouse from the outside is up to everyone to decide for themselves. There is still no consensus here. Some are definitely for insulation, while others are categorically against it. But if you decide to insulate the bathhouse from the outside, you need to do this according to the principle of a ventilated facade: leaving a gap between the outer wall finish and the waterproofing layer. In this free space, air masses, due to the difference in atmospheric pressure, actively move upward, carrying with them water vapor. And this is the main task of drying the walls after bath procedures.

The operating principle of a ventilated façade

Bathhouses made of wood - from timber or logs - are almost never insulated from the outside . Wood is a unique material that retains heat well and copes with condensation on its own. The main task in such baths is to carefully seal the inter-crown seams. It is better to seal cracks and crevices with materials that have antiseptic properties. It’s not for nothing that our ancestors caulked baths exclusively with moss - it is a wonderful natural antiseptic that successfully fights the development of fungi and mold.

Saunas made of wood and without external insulation cope well with the problem of removing condensation

If the bathhouse is built from cinder block, foam concrete or any other building block (you can build a bathhouse cheaply from expanded clay concrete blocks), then you cannot do without external insulation. But insulation must be done correctly, according to the principle of a ventilated facade, making sure to leave gaps for the fastest and most complete removal of condensation from both the walls and the insulation. If you decide to line a bathhouse made of building blocks with finishing bricks, siding, or a block house, a layer of thermal insulation is required between them.

An option for exterior finishing of a bathhouse made of building blocks, which simultaneously solves the problems of thermal insulation and condensate removal

To avoid premature destruction of a brick bathhouse, most experts advise insulating the walls not from the outside, but from the inside. And the internal insulation should be done according to the principle of a ventilated facade, the layers of insulation should be maximum, the sealing of vapor barrier seams should be thorough, it is desirable to use foil materials as a vapor barrier - for maximum heat reflection into the room.

The fact is that ceramic brick is very hygroscopic and it retains moisture for quite a long time. The walls of a free-standing unheated brick bathhouse will certainly freeze in winter. If, with each visit to the bathhouse, the brick freezes and then freezes again, it will very quickly exhaust its strength limit: and after a year or two or three of regular use of the brick bathhouse in winter, its walls will begin to collapse. Therefore, the main task in a brick bathhouse is to protect the walls from the inside as much as possible from heating, while simultaneously solving the problem of retaining heat in the room.

The walls of a brick bathhouse must be insulated from the inside. External insulation is desirable

External insulation of a brick bathhouse would not be amiss, but the main task here is to protect the walls from precipitation, while achieving good ventilation to quickly remove moisture from the walls.

If you decide to insulate the outside of a bathhouse made of wood (the bathhouse takes a long time to warm up even after caulking the seams), the insulation will be similar. Perhaps the thickness of the heat insulator will be smaller, but the principle is the same - a mandatory ventilation gap. What is the sequence of layers of the insulation cake and the features of insulating baths depending on the wall material, read in the article “How to insulate and what to cover the outside of a bathhouse with.”

Conclusions : calculating the dew point in a bathhouse is almost impossible. When the temperature and humidity in the room changes, it shifts towards the outer wall when heated, and then, when cooled, in the opposite direction. Therefore, it is not important to determine the dew point (although it needs to be taken into account), but the competent selection of materials and their correct placement in the insulation cake.

How to change the location of a point

If errors in calculations are made during the construction of a new house, this can lead to the permanent formation of mold on cold surfaces and further damage to the entire structure.

A problem in a house that has been in use for a long time can be solved by changing the main influencing factors. The following measures are provided for this:

1. Organize a reliable ventilation system. If a finished building (guest house, bathhouse or cottage) is used temporarily, for example in the summer, you may notice an increase in humidity levels in all rooms. The best solution is to organize a ventilation system that provides good air exchange at any time of the year.
2. Additional heating. If condensation persists on the ceiling, it means that the heating of the room is not sufficient to reduce the humidity level. The best solution is to additionally use portable heaters or household dehumidifiers.
3. Make the building thermally insulated. You can move the point towards the street using façade insulation. Why is it useful to insulate walls outside? In this case, the condensation point will be between the insulator and the wall, so that even in the event of significant changes in climatic conditions, surface moisture can be prevented.

When determining the location of a point in the wall, many factors must be taken into account: climatic conditions, wind strength, sun angle, temperature, humidity conditions inside the building, floor thickness and materials.

The minimum level of humidity is specific to each type of material; the main thing is not to allow it to increase significantly. In addition, each homeowner can determine the temperature of the condensation on the surface. If thermal insulation technology is used, you can be sure of reliable protection and durability of the walls.

Nuances of wooden construction

The construction of any object made of wood requires compliance with several stages in relation to the material itself:

• Correct choice of timber. For any facility, the moisture content of construction raw materials should not exceed 8–12%. Otherwise, the raw crowns will begin to twist in the finished box, causing gaps and cracks to appear in the array and reducing the safety of the assembly.
• Maintaining the shrinkage period. You cannot carry out finishing manipulations or insert doors and windows if the period of primary shrinkage is not met - in the first year after construction it is especially intense.
• Wood protection. A bathhouse is a “wet” object, therefore, protecting the crowns from the outside and inside from the formation of mold and rot is the main task. No less important will be the procedures for impregnating surfaces with fire retardants (fire-retardant compounds) and liquids that repel parasites and rodents.
• Creation of ventilation. For long-term operation of the bathhouse, it is necessary to keep the crowns dry. It is especially important to carry out high-quality installation of air ducts if it is decided to arrange a thermal insulation cake with subsequent cladding.

At all points, the determining factor in the quality of construction is the humidity of the timber and the air - it should not cause damage to the material. Determining the dew point is an important parameter that adjusts the construction of a bathhouse.

Factors influencing heat loss

Thermal processes correlate well with electrical processes: temperature difference acts as voltage, heat flow can be thought of as current - there is no need to create a special term for resistance. The concept of least resistance, called thermal bridges in heating engineering, is also completely correct.

If you consider any material in cross section, it is quite easy to determine the path of heat flow at both the micro and macro levels. As the first model, we will take a concrete wall in which, due to technological necessity, the through fastenings are made with steel rods of arbitrary cross-section. Steel conducts heat slightly better than concrete, so three main heat flows can be distinguished

• From steel bars to concrete
• Through the thickness of concrete
• Through the steel bars

Heat loss through thermal bridges in concrete
The most interesting model is the final heat flow. Because the steel core heats up faster, the temperature difference between the two materials will occur closer to the outside of the wall. Thus, the steel not only “pumps” heat out itself, but also increases the thermal conductivity of the adjacent concrete masses.

Thermal processes in porous media proceed according to a similar pattern. Almost all building materials consist of an extensive network of solid materials, between which there is a space filled with air. Therefore, a solid, dense material is the main conductor of heat, but due to its complex structure, the path along which heat moves is larger than its cross-sectional area. Therefore, the second factor determining thermal resistance is the heterogeneity of each layer and the entire building envelope.

Reducing heat loss and shifting the dew point in the thermal insulation of external walls

Useful tips

Ventilation must be ensured in such a way that the relative humidity in the home does not exceed normal values ​​(40%-60%). This requires an air flow from outside. In houses and apartments with natural ventilation, it should enter through the cracks in the windows.

But when you replace windows with sealed vinyl windows, there is no air flow. Ventilation does not work, even if the exhaust ducts are equipped with fans. This problem can be solved by installing window or wall valves.

Also make sure there is a gap under the inner door.