What to do if the front metal door sweats?

➤ Sometimes drops of moisture appear on the door, as if it crying or sweating. Why is this happening, is it bad for the door and how to deal with such a phenomenon? Let's figure it out ☑

Sweating an entrance metal door

To begin with, we will talk about the reasons for this phenomenon. Moisture on the door is condensation that appears due to the difference in temperatures inside and outside the house.

That is why drops rarely appear on the doors in the apartment and often on the doors in private houses. The front door of the metal has a greater speed of temperature than the walls of the house, and therefore becomes a cold bridge on the border “street-house”. It often happens that the front door box sweats, because it is not insulated.

Metal parts are enhanced by the effect of the “sweating” of the doors with which the door is equipped and which pass through the canvas through (stiffeners, box, lock, etc.).

When you take a hot shower in the bathroom, on the mirror and even a wooden interior door, moisture forms. And when boiling a kettle on the stove in winter, water appears on the windows.

But why is this happening? Let us turn to the definitions and laws of physics.

What is condensate?


Condensate is a liquid formed when steam transition to a liquid state at a surface at a temperature below the dew point.

The dew point is the temperature value below which the water vapor contained in the air becomes saturated and goes into a liquid state. The dew point depends on the humidity of the air, air temperature and surface temperature.

There are tables where it is calculated in what conditions moisture will appear on the door surface. For example, when 25 degrees of heat and 50% relative humidity inside the house, the dew point is reached at 13.1 degrees. So, if the surface of a wall or door cools up to 13.1 degrees, condensation forms on it.

Air temperature

The temperature of the dew at the relative humidity of the air (%)















-10 ° C.

-5 ° C.

0 ° C.

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+9 ° C

+10 ° C

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+24 ° C


+25 ° C

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+29 ° C

In most regions of Russia, it is cold in winter, and therefore moisture condenses at the front doors. Even on those that are in apartment buildings, if the entrance is poorly heated. This problem is especially relevant for residents of the first floors where cold air accumulates.

Why is condensate harmful to the front metal door?

The accumulation of moisture on the door, especially in large quantities, negatively affects the appearance of the door and its functionality. The door finish absorbs the liquid and swells. When water enters the structure, the porous filler also absorbs it into itself. Because of this, its insulation properties worsen.

Do not forget that the metal parts of the doors are subject to corrosion, which means that rust may appear on them.

However, a high-quality front door is adapted for such conditions. The finish must be moisture resistant – PVC-coated MDF panels are suitable for apartment doors, panels with moisture-resistant enamel, marine plywood panels are suitable for outdoor doors.

Many people think that condensation on the door is an indicator of a “bad” door. However, this is caused by a natural phenomenon and is not related to quality. The front door can be insulated, airtight and keep the cold out of the house, but moisture will still appear on it.

And even vice versa! A low-quality cheap door does not suffer from condensation, because it lets cold air into the room. And it turns out that the house is cold, but there is no water on the door.

I want the house to be warm, and the front door does not sweat – what to do?

Metal front door sweats: what to do?

In a private house, the best option is to purchase a high-quality door designed for use at the street-house boundary. Such doors have specially designed insulation, including insulated and metal elements. Due to this, there are no cold bridges, which reduces the risk of condensation, but does not completely remove it. Also, reliable manufacturers use anti-corrosion treatment for the metal parts of the door.

If the door in the apartment is sweating or you do not plan to buy a new door in the near future, you can use some tricks.

The simplest of them:

Ventilate the room
When the windows in our car fog up in winter, we turn on the heating and ventilation. The glass in the kitchen is fogged up from the kettle – open the window. The same rule applies at home. Open windows and front door for 10-15 minutes.

Remove the source of moisture from the corridor
It could be a wet shoe mat. Condensation also forms during repairs, when the floor is poured, for example, because the humidity in the room increases greatly.

Lower the temperature
Builders recommend lowering the temperature in the front door area. So the temperature difference between inside and outside will be less. This is possible if you have regulated batteries. But if this is not possible, go to step 4.

Dry the air
In order to reduce the humidity of the air, batteries are placed under the windows. The same drying devices can be installed next to the front door. Here, however, it is worth thinking about your health, since humidified air is useful for a person, so we get sick less often.

More complex and effective methods for removing moisture from the door:

Arrange ventilation next to the door
Ventilation in a private house is a solution to many problems at once. This is the absence of stuffiness, and a decrease in condensate on a metal door. One option is to make a complete air exhaust system. Another and simpler one is compact air handling units. So the air from the street penetrates into the room, which in winter is much drier than indoors. And less humidity inside means less condensation on the door.

Build a vestibule in front of the front door
An unheated vestibule smooths out the contrast of temperature and humidity inside and outside the house. But you need to understand that it is expensive.

Install the front door with heating
Buying a heated front door is an effective way to eliminate condensate. As a rule, heating elements are built into the box. Installation of heating the door frame is possible in your door.

The door surfaces heat up, which removes the difference in temperature inside and outside, so moisture does not appear.