Basement ventilation in a private house: the best ways to arrange proper air exchange

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Tatyana Zakharova
Last update: May 2019

Basement ventilation, as well as the ventilation of any living room, is necessary to ensure that the exhaust air changes are fresh. Thanks to the organized air exchange, the cellar or basement becomes suitable for use as a pantry, storage for vegetables or fruits.

If you take up the improvement of the basement more seriously, then in this area you can place a pool, garage or home gym. However, the ventilation of the basement in a private house has its own characteristics. It is about them that we will speak in more detail in our article. We will analyze the rules for arranging ventilation in the basement during natural air exchange, as well as in the case of forced ventilation.

Features of creating a residential microclimate

There are many reasons to tackle a full-fledged, properly functioning basement ventilation system. They concern both the preservation of the building structure and the provision of an atmosphere conducive to living.

Stagnation of air masses, lack of ventilation lead to the fact that fungus and mold affect all objects in the room - from things and products to walls and foundations.

Fresh vegetables in the basement
Fresh agricultural products stored in the cellar require special conditions. In addition to a certain temperature and humidity, it is important to change the air to prevent rot or mold

To create a comfortable microclimate in the cottage, it is important that cellar, and the attic, and all other technical and residential premises were equipped with a ventilation system. Therefore, the methods of its device are thought out even when planning when a house project is being drawn up.

Among the most rational methods is the arrangement of supply and exhaust channels, as well as holes in the walls, providing a natural change of air.

Outlets in the foundation of the house
So that air exchange is carried out regardless of the presence of a person, and a comfortable microclimate is maintained in the basement, elementary methods of ventilation are used - vents are made and natural ventilation is organized

If you do not take into account the installation of special electrical equipment, the ventilation system is based on the well-known laws of physics: heated air rises and leaves the room through a pipe, and cold air enters, replacing it, through a second pipe.

A two-pipe air exchange system is based on this principle.

A simpler version with one pipe is also used - when fresh air enters through openings in a wall or foundation, and exits through an upstream line.

Basement ventilation scheme
One of the simple solutions for arranging basement ventilation. The scheme is simple, understandable and affordable, but it is necessary to start designing it in advance in order to implement it in the process of wall and roof construction

When building any system using ventilation pipes It is important where to organize the air intake and at what height the channels should be led out. The length and diameter of the pipes are also calculated so that the ventilation system works with maximum effect.

Basement ventilation types

Basement ventilation systems of private households are classified according to general principles. For example, by the method of organizing the pressure of the transported air, they are natural or forced.

Consider the features of both types, since structural differences affect the choice of materials and installation method.

Option # 1 - natural air exchange

To organize the circulation of air masses without connecting additional equipment, it is necessary to create conditions under which air exchange would be carried out only due to the difference in pressure and temperature. This is a variant of supply and exhaust ventilation, typical for residential premises.

The principle of operation is simple: the cellar space is filled with cold air from the street, coming in through the air inlets and pipes, and the waste medium is discharged through the exhaust duct.

Two cellar ventilation options
Two options for arranging ventilation in the cottage. The first solution is optimal for basements connected to residential premises, the second - for basements and cellars with a separate entrance

The advantages of a natural ventilation device are ease of installation and low costs for the purchase of components. You can purchase pipes and install them yourself.

The easy-to-use natural circulation system also has disadvantages. The main one is dependence on external factors. Air exchange quality may suffer from sudden changes in temperature or pressure, as well as from atmospheric phenomena such as strong winds or heavy rain.

Designing a natural system is best done in advance, until the walls are erected. It is necessary to select the pipes of the desired section, to consider their location.

What elements will be required for the equipment of the basement ventilation system can be determined only after analysis of the design of a specific basement. However, there are components that can be called universal:

A few installation recommendations:

  • Exhaust duct positioned as high as possible. Traditionally, it leads from the ceiling of the basement to the roof of the building and goes about 0.5-0.6 m above the roofing.
  • Hood equip along the outer wall or parallel to one of the main walls, if other rooms are connected to it, for example, bathrooms.
  • The supply pipe is installed above the cement base. or flooring of the basement, at a height of 0.3-0.4 m, its second end is brought out above the ground.
  • The average diameter of pipes and ducts is 120-150 mm, for large basements use products up to 200 mm.

If you break the basic rules, problems may arise. For example, if the end of the exhaust pipe is lowered at least 0.2-0.3 m below the ceiling, then dampness will appear in the room - stagnation of air under the ceiling will lead to mold.

Option # 2 - forced ventilation

Many people stop at the natural ventilation system of their basement and do not think about the fact that it loses its effectiveness due to natural factors.

More prudent building owners go further - complement the design with forced air circulation devices. Simply put, installed in pipes fans.

Exhaust fan
If, for some reason, air stagnates, the fans on the supply and exhaust pipes are activated, as a result of which full circulation is ensured

How to determine that there is a need to install additional equipment? If, coming from the street or from the living room, you feel a lack of fresh air and try to ventilate the basement - natural ventilation can not cope.

If a living room is equipped in the basement or basement, there may be a problem in the supply of too cold air through the supply devices, especially in winter.

So that already heated air masses enter inside, set heater or air conditioning. In addition, the system is equipped with additional noise insulation and high-quality air filters.

What kind of ventilation is better to choose? It is believed that the combined method is most appropriate when, with insufficient effectiveness of natural circulation, you can use forced.

Basement fan
The reasons for the stale air can be in insufficient supply, and in the wrong diameter of the exhaust duct, and in the heat that has just settled on the street. An inexpensive fan connected to the power supply system really helps in such moments

Typically, fans and other devices "rest" in the off-season, when air exchange is due to the difference in temperature and pressure.

In cold weather, it is often necessary to close the supply devices due to the too low temperature of the incoming air, and in the summer use fans or air conditioners.

Duct Installation Rules

There is no universal scheme for arranging the ventilation system - it all depends on the volume of the room, the structure of the building as a whole, climatic conditions and even the material from which the house is built.

Therefore, we consider the general rules that may come in handy when installing ventilation ducts.

Features of planning and calculations

Important points - correctly calculate the size of components and choose the place of their installation.

To equip a cottage intended for permanent residence, it is better to make project forced ventilation system. It can work offline and does not depend on natural factors.

For installation you will need:

  • pipes for exhaust and supply ducts;
  • fans or other discharge units;
  • air intake for the supply air duct;
  • deflector or visor for the exhaust duct;
  • diffusers, tees and adapters for connecting pipes.

Asbestos-cement pipes are used less and less due to fragility, transportation and installation features. But they do not need to be insulated, and they are relatively inexpensive.

More often used plastic and galvanized steel products. The former are characterized by ease of processing and low weight, the latter - by durability and a long service life.

Sewer drain pipe
One of the most common elements for the ventilation system of basements and cellars is a sewer pipe, the cross section of which depends on the size of the room

How to determine the diameter of the channels? To equip a large garage, pool or basement, it is better to invite specialists who use a complex calculation algorithm that takes into account all factors.

But for installing a ventilation system in a small basement of a private house, you can apply a universal counting scheme.

Suppose you need ducts for a small basement of 10 m². We multiply this number by the average coefficient - it is assumed that for each square. square meter required 26 cm² pipe cross-sectional area: 10 x 26 = 260 cm².

Then we find the radius according to the formula: R = √ (T / π): √ (260: 3.14) = 9.1.

Multiply the radius by 2, we get the inner diameter: 9.1 x 2 = 18.2 cm.

Therefore, the recommended pipe diameter for the duct is approximately 18 cm.

You can also use tables provided by duct manufacturers or online calculation tools. Results will be more accurate.

Hardware Installation Recommendations

Assume that the basement in the house is already equipped or is under construction. The sequence of installation of the exhaust and supply lines is not important.

A hole must be made in the ceiling for the pipe, taking into account the fact that it will go higher - either through the living quarters, or along the street, near the wall, but in an insulated version. Most often, this is a place in the corner, near a chimney or insulated wall.

We recommend that you familiarize yourself with building regulations node passage ventilation through the roof.

Ceiling ventilation pipe
The box or pipe is inserted into the hole so that it falls below the ceiling by no more than 100 mm. The remaining free space is filled with mortar and insulated

The canal is led out of the roof by at least 0.6 m, but sometimes the height of the segment above the roof surface reaches 1.5 m. The upper part is equipped with a visor so that debris and moisture do not enter the canal. If you also install a deflector, then you can count on an increase in traction.

Moisture will precipitate from the temperature difference on the inner walls of the pipe, so a condensate collector is installed in the lower part, which must be periodically released if the water does not evaporate naturally.

Then proceed to the installation of the supply line. In the opposite corner or against the wall, a second pipe is fixed. Its end should be as close to the floor as possible - preferably at a distance of 0.2-0.4 m.

Through a hole in the foundation, the pipe is led outside and raised above the surface. The upper part is equipped with a grill or mesh.

Basement air intake
The lower the intake hole, the greater the difference in temperature and pressure. Consequently, air circulation at the lowest possible location of the supply channel will occur more actively

If you are not too lazy and install simple devices on the pipes - dampers, then the air intake can be regulated.

To create the simplest forced system, fans are installed on both pipes. On sale you can find household appliances designed for different pipe diameters with round and rectangular cross-section.

Pipe exhaust fan
The fan must not run continuously. In periods when natural ventilation is sufficient for proper air exchange, it is simply turned off

After installing the system, you need to test it. To do this, use the simple "grandmother" method - bring a sheet of paper to the exhaust hole. With good traction, it “sticks” to the grill.

Instead of a sheet, you can use a lit match - the slope of the flame tongue can judge the effectiveness of the hood.

Arrange a system with one pipe or other inferior ventilation options is impractical. Supply and exhaust ventilation with two types of ducts and forced circulation elements is recognized as the most rational and simple in execution.

Conclusions and useful video on the topic

The use of automation in amateur performance:

User opinion on forced ventilation:

Which pipes are better suited for basement ventilation:

If the house is built by experienced builders, then even with the foundation equipment they worry about ventilation in the basement. Installing the system in prepared walls and floors is much easier..

However, do not despair if the house is already built, and ventilation works poorly - you can always find a way to increase its effectiveness.

Do you have any questions about the arrangement of ventilation in the basement? Ask them under this article - our experts and other site visitors will try to help you.

If you want to share the experience of your own ventilation equipment, tell us about it in the comments section.

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Visitors Comments
  1. Leonid

    A dry and well-ventilated basement is the key to the absence or at least a marked reduction in the formation of condensate, and with it mold and other harmful microorganisms. Unfortunately, natural ventilation is far from always doing its job. Another thing is the forced air exchange system. To build it is not particularly difficult, but the “exhaust” will be significant - you can safely store food without fear of rot, mold, etc.

  2. Tatyana Dmitrievna

    In my basement for a long time there was only ventilation through a pipe brought out. Passive, as it is also called. Better than nothing, but damp and all sorts of smells in the basement were always present, even in the hottest summers. Then the son made forced ventilation. To say that now there is not a single smell, it is impossible, but it has become much better. At least non-condensing walls are now year-round.

  3. Sasha

    At the dacha in the basement there is one supply and exhaust hole, but condensate still accumulates. Either the diameter is small, or something else. If you put a duct fan should help? And where is it better to bet - at the entrance or at the exit?

    • Expert
      Alexey Dedyulin

      It may not be about ventilation. It is possible that you need to make insulation and waterproofing of the building envelope (outside). If everything is in order with this, then feel free to make a good ventilation system, then condensation will not form.

      My cellar is in the garage and the ventilation scheme is as follows (attached photo). I recommend using flaps on the supply valve (see photo), with which you can adjust the speed of the air flow through the cellar.

      Attached photos:
    • Maxim

      If there is one fan, then it is better to put it on the hood and it is not necessary to do this in the cellar. Better to put on the hood and on top of the pipe.