How to make ventilation and extractor hood in the cellar

Recommendation points

• Winter and summer operating modes
• Supply and exhaust duct arrangement
• Ventilation schemes
• Forced ventilation and air conditioning

Maintaining a microclimate in a basement or cellar is not always easy. It is good if the climate and conditions of the accommodation make the temperature and humidity acceptable naturally. But such cases are extremely rare, usually the issue of organizing the ventilation system falls entirely on the shoulders of the developer..

Winter and summer operating modes

Properly installed ventilation is the key to an optimal climate in the basement. The main task is to ensure a smooth temperature drop from the cold zone at the floor to the warm one at the ceiling. Temperature limits and differences have different meanings for each season.

In summer, when vegetables are not stored in the basement, the temperature at the floor can rise to 10–12 ° С, while the maximum recommended temperature is 15–16 ° С. Excessive outdoor air intake will lead to an increase in temperature, which negatively affects the shelf life of canned food. In winter, the supply air is cold, therefore, with an overabundance of capacity, another problem arises – cooling the basement.

The air flow can be controlled forcibly by means of a fan or naturally due to the correct location of the supply and exhaust ducts.

Supply and exhaust duct arrangement

The inner edge of the pipe through which air will flow into the basement should be as low as possible. It is recommended to make a side entry through the basement wall, and then lay the pipe at the same depth for about 3.5–4 m. This is necessary so that excessively cold or too hot air has time to pass heat exchange with the soil through the pipe walls, and thus the temperature of the incoming air reached optimal.

Optimal ventilation scheme of the cellar: 1 – supply channel; 2 – inlet of the tributary, closed by a grating from rodents and a cone; 3 – outlet of the inflow in the lower part of the cellar at the farthest point from the entrance; 4 – exhaust channel; 5 – ventilation grilles of the hood are distributed near the entrance to the basement under the ceiling; 6 – the exhaust pipe rises 3-4 m above ground level and is protected by a cone or weather vane

In the summer, condensation can form in the inflow channel, therefore the horizontal section must have a slope towards the basement. In order for the recuperative function to be well expressed, the pipe material should not impede the heat flow, therefore it is recommended to use steel or technical HDPE pipes. The exit of the pipe to the surface should be located 40-50 cm above the ground in a shaded place, equipped with a rain fungus and a mesh that protects against rodents and insects.

The exhaust duct collects heated and gaseous air under the ceiling as far as possible from the supply pipe. Thus, air circulation will not have dead zones, and the temperature difference will become well pronounced..

The chimney, if part of a natural circulation system, should have a minimum number of bends. That part of the exhaust duct, which is located above the ground and in the freezing soil layer, should be insulated and positioned strictly in a straight line. The main task is to bring the exhaust duct by the shortest route to such a height where the ejection, the pressure and temperature difference will provide sufficient duct performance.

Typically, the chimney is only raised to the edge of the aerodynamic dead zone, that is, to the level of the ridge. If at the same time the air exchange remains insufficient, the pipe grows higher, or is supplied with a deflector. As a rule, the need for forced ventilation becomes clear at this stage..

Ventilation schemes

Cellars can have different cubes and be equipped in different ways. The classical scheme with one supply and one exhaust duct is sufficient for a room volume of 10-12 m³, but how to organize ventilation of the basement with heating and full interior decoration?

Planning plays a primary role in this matter. The bulk of the fresh air should flow exactly into the room where the food is stored. Taking part of the temperature from the room, the air moves further along through channels, spaced both in level and at the point of entry into the room.

For example, air from the storage room enters through the through ventilation ducts near the ceiling, enters the corridor and follows it, flowing into the rooms through the ducts near the floor. At the same time, one root exhaust canal is stretched through the rooms themselves. Its exits are connected to the ceiling ventilation grilles by flexible pipes and are located at the greatest distance from the through channel near the corridor.

Bringing an inflow into the basement is much easier than arranging an exhaust hood. The supply channels are less visible, for most of their length they follow underground. Therefore, a ventilation scheme is common, according to which air is supplied to different rooms individually, and is collected by a common exhaust system..

Systems with separate ventilation cycles are based on the same principle. You may not want to smell the storage room when you are in the break room. In addition, it makes sense to take air from living quarters upstairs for a more favorable temperature regime. Finally, one supply channel may simply not be enough: a channel with a 100 mm passage provides ventilation of a space with a volume of 10-12 m³, the frequency of air exchange in the basement should be in the region of 4-6.

Forced ventilation and air conditioning

To have a greater degree of control over the ventilation system, a number of technical means are used. The easiest way is to provide a natural convection system with redundancy, and then adjust the air flow to your liking. The gate valve is installed on the exhaust duct and is used as follows:

1. If warm air entered the basement for a long time, for example, through the door to the house, which they forgot to close, the valve opens completely for a while to ventilate and evaporate moisture and returns to its place when the minimum permissible temperature is reached.
2. In winter, the more the valve is open, the lower the temperature in the basement and the less pronounced the difference.
3. In summer mode, the valve is installed in a position at which the minimum air exchange is ensured in the basement and the smell of dampness is not noticeable.

Naturally, natural circulation cannot be the only solution, both due to lack of efficiency and to preserve the aesthetics of the roof and façade. In this case, the system is equipped with an exhaust duct fan, while air can be discharged at almost any height, but at a sufficient distance from the supply pipe.

The use of multi-mode fans is recommended. They are better suited for maintaining an indoor climate that is largely dependent on outdoor weather conditions. However, even with a constant fan performance, it is possible to provide regulation with a gate.