Natural ventilation in a private house: rules for arranging a gravitational air exchange system

Implementation of simple ventilation systems

You can develop a ventilation system project and implement it on the territory of your own home. You can do without the introduction of complex modern systems that require qualified installation, clear calculations, significant cash costs. The article will focus on devices that can be installed by every homeowner. This is a ventilation system.

Features of effective ventilation in a private house

Recently, the problems associated with insufficient ventilation have been of particular concern to the owners of their own properties. The owners of old buildings were also worried about the lack of fresh air, but not so acutely. The old construction technologies involved the use of building materials and the introduction of special building elements that promote natural ventilation in full force.

Doors and wooden window frames were covered loosely, which significantly contributed to the involuntary ventilation of the premises. Even the walls were built from building materials, which could not be considered insurmountable obstacles to air exchange. All elements of the house seemed to "breathe". Food was cooked in the oven, and the open chimneys themselves became powerful and highly efficient ventilation ducts.

There were no ventilation problems in the old house designs - they themselves provided a constant exchange of air.

Now, when modern-type houses are being built, the situation with the identification of the effectiveness of natural ventilation is changing significantly. Owners of private quadrature seek to minimize heat loss. Buildings are “stretched with warm clothes” in the form of layers of thermal insulation. Yes, thermal insulation materials retain heat, but the house "pays" with the fact that it does not allow air to pass through.

A significant role in organizing a comfortable stay is played by the presence in a private house, in addition to living rooms, also:

• bathroom;
• toilet
• bathroom;
• shower room;
• kitchens.

So you should think carefully about the design of ventilation, otherwise the house will soon become a "storehouse" of discomfort and a distributor of various diseases.

Temperature controlled ventilation system

Temperature controlled ventilation system

In this system, in addition to the air conditioning unit, special devices are installed that help to lower the temperature to the desired parameters in each individual room. This allows you to separately adjust the temperature in each individual room. It is advisable to place the supply openings in such a system either in the basement or in the utility rooms of the first floor (if there is no basement in the house), this can significantly reduce the noise level when installing these devices.

Principles of operation of ventilation

Previously, housing was built with wooden windows and doors. Moreover, they did not shine with special tightness. As a result, a constant and natural exchange of dirty indoor and clean outdoor air went through the existing gaps.

However, now they have been replaced by plastic window and door blocks, which are an order of magnitude more airtight. Therefore, as an option, they put a special device on such windows - a supply ventilation valve.

The most common mistake when arranging ventilation in an old house is installing windows with double-glazed windows without rebuilding the existing natural-looking ventilation system, which is no longer able to cope with the proper flow of fresh air due to tightly closed sashes.

The principle of operation of the house ventilation system is based on the continuous influx of new air masses from the street. As a result, they gradually replace the air in the rooms, squeezing the old out. This removes carbon dioxide, odors and moisture from the house.

The points of inflow of new air are:

• window;
• doors;
• vents in the foundation and basement;
• window air conditioners.

We talked about supply ventilation in detail in the following material.

The removal of used air from the premises occurs through windows and doors during ventilation, as well as a ventilation pipe (shaft) or an exhaust valve.

Option #1 - Natural draft system

The non-mechanical type ventilation system works due to the formation of natural draft in a vertical pipe.

This is the principle of operation of a classic wood-burning stove or fireplace chimney. In both cases, pressure is created at the bottom, pushing the air up and out.

The greater the difference in pressure and temperature between the street and the rooms in the cottage, the stronger the draft in the ventilation shaft

Also, the traction force is affected by the saturation of the air with moisture. The drier it is, the heavier it is. Humid air masses inevitably tend to rise under the ceiling and further into the ventilation duct if it goes outside the building.

The main disadvantage of natural ventilation lies in its poor controllability. In high winds, reverse thrust is possible. In winter, thanks to the temperature difference, the system works very efficiently, in some situations even excessively, extracting precious heat from the house.

And in the summer, its effectiveness drops dramatically. The temperature indicators in the rooms of the cottage and on the street in the summer do not differ much, so the draft inevitably decreases.

With gusts of wind, the air in the ventilation can go back through the ventilation duct back into the rooms. The formation of reverse thrust is an infrequent phenomenon, but quite possible

To control the quality of air exchange in such a system, the ventilation ducts in it must be equipped with check valves. If necessary, it will be possible to cover them in order to reduce the natural draft.

Option #2 - Forced Awakening System

If the natural ventilation system is not able to maintain the proper microclimate in the cottage, then it has to be changed to supply or exhaust mechanical ventilation.

In this case, air flows to move through the interior are forced with the help of fans.

A combined variation of the system is also possible - with a supply and exhaust scheme. In it, the volumes of both inflow and exhaust are controlled by ventilation units.

In the supply system, clean air is forced into the house by mechanical devices, and it leaves by itself in the ventilation shaft. In the exhaust, it is drawn out by a fan, and the inflow is carried out through the ventilation holes in the walls

In some situations, in such a system, an additional heat exchanger is installed, which takes heat from the air from the rooms and then gives it to the street.

Exhaust fans are installed in each room or one per ventilation shaft. And air supply devices in private houses are usually equipped in the form of wall-mounted ducts-holes with an axial electric fan inside.

But a variant is also possible with a single air blower and ventilation ducts throughout the building.

If supply and exhaust ventilation is done, then it requires two separate ventilation ducts to be laid - one goes to the exhaust, the second to the inflow.

This seriously affects the cost of the system, but allows for more precise regulation and control.

Why does a building need ventilation?

The use in the construction of modern materials and various external enclosing structures of a cottage / house makes it difficult for natural air exchange between rooms and the street, and sometimes even blocks it. Thanks to the internal and external insulation, the installed plastic windows of the building become airtight.

Such measures contribute to the conservation of heat and energy savings, but greatly impede the flow of fresh air. To correct this typical situation, it is necessary to organize an effective air circulation system.

In a building, ventilation is needed so that fresh air regularly enters the bathroom, bedroom, living room and kitchen not through open windows and doors, but through special devices - anemostats and air diffusers.

According to generally accepted sanitary and hygienic standards, a properly functioning ventilation system is an indispensable element of the engineering equipment of all residential facilities.

A constant flow of air in the house will provide comfortable conditions for long-term residence of people and the maintenance of plants, as well as for the full functioning of all technical systems.

Ventilation is also necessary to maintain optimal environmental parameters for the safe operation of various building structures, wooden furniture and interior items.

The circulation of air flows must be organized not only in living rooms, but also in utility rooms - bathrooms and bathrooms, in the kitchen, in the boiler room and basement.

A high-quality ventilation system contributes to the rapid removal of excess moisture and heat. Together with the exhaust air, harmful microorganisms, accumulated dirt and dust are simultaneously removed from the premises.

The organization of the outflow of polluted air is a preventive measure in the difficult fight against fungus and mold

That is why it is important to think over all the details of the engineering network even at the design stage of a residential building: to make the ventilation in the kitchen more powerful than in other rooms, to choose the right functional elements of the ventilation system in order to ensure the optimal level of oxygen in the interior

How natural ventilation works

How natural ventilation works

It is necessary to determine the conditions in which only natural ventilation is allowed. Ventilation systems are designed according to different schemes, but the main groups can be distinguished.

First group. Installation of forced ventilation. Through mechanical action, air flows are introduced into the room and removed. Special fans are used.

Ventilation schemes are created:

• supply;
• exhaust;
• combined (with the participation of both exhaust and air inflow).

It is customary to entrust the installation of such systems to professionals, since the performer must have technical skills and be able to make calculations. These systems are complex, expensive, but they allow you to fully control the quality of the air that enters the room.

Second group. Creation of natural ventilation. Air masses circulate naturally, without artificial supply and forced pulling. Only the laws of physics are taken into account, and only natural factors control the airflow.

Forces affecting the state of natural ventilation

Temperature drop. Warm air has a lower density than cold air. Its mass is also less, it is lighter.Warm streams tend to rise, it remains to organize an exit for them from the room. Instead, flows of new air come in - less heated.

Pressure drop. The ventilation ducts are arranged vertically. The height of the rise of these structures is important, because a pressure drop is created in the channels. This indicator is not so significant, but still contributes to the movement of air masses.

The impact of the wind. Drafts in the room contribute to better air filtration. However, a strong wind can block the outlet of the exhaust air from the duct and even drive the air flow in the opposite direction - into the room. This is provided that the ventilation duct is designed with flaws.

And many homeowners noticed some hums in the ventilation system. It is an open system, so it reduces the overall level of soundproofing. The source of noise can be both vehicles moving along the road and the rumble of the wind. That is, sounds penetrate both through the output channel and through the windows.

It's important to understand. Only then living conditions can be considered comfortable if it is possible to optimally combine the following parameters:

• air temperature;
• its saturation with oxygen;
• relative humidity;
• noise level.

All these indicators are taken into account when choosing materials that are capable of accumulating thermal energy. So houses are being built:

• from brick;
• from cinder blocks;
• from expanded clay concrete blocks;
• from ceramic blocks;
• from gas silicate blocks.

In order for such a scheme to function normally, it will be necessary to correctly design the supply and exhaust channels. Then the air will become freely moved between them.

It is necessary to correctly plan the location of the ventilation ducts for air intake and exhaust

Air intake

Fresh air enters the room through:

• window openings;
• doors (if we are talking about a mansion);
• intake ventilation valves for special purposes.

In the room, the air is heated due to heat transfer from various devices, from a burning fire, from the bodies of living inhabitants. And then the denser air, saturated with carbon dioxide, is displaced by new streams. The exhaust air is squeezed out, and it finds a way out in those rooms where ventilation vents are installed.

In order for the air to move freely without encountering insurmountable obstacles along the way, gaps are made between the door leaf and the floor level. You can install through windows directly in the doors.

Factors affecting the speed and volume of air flow

The efficiency of natural ventilation is due to natural factors, which can reduce energy costs for home maintenance by 10-30%.

The list of constituent elements involved in natural air exchange:

1. Outdoor and indoor temperature. The greater the difference between the outside and inside temperatures, the greater the speed and volume of air masses. In the cold season, natural ventilation functions most productively due to the maximum difference in air density. With the onset of heat, the values ​​of the specific gravity of outdoor and indoor air will begin to equalize, which will lead to a weakening of draft. In summer, when the outdoor air temperature reaches 28-30ºС, and in the room - 22-24ºС, there is a reverse draft effect, which in no way indicates a malfunction of the ventilation system.
2. Features of the arrangement of the exhaust pipe.The higher the exhaust pipe above the surface, the lower the atmospheric pressure, therefore, the stronger the draft of air flows from the premises.
3. Air humidity. An increase in the relative humidity of the air during natural ventilation reduces the rate of air exchange.
4. Wind speed and direction. The increase in wind force contributes to a decrease in pressure at the end of the exhaust pipes, thereby increasing the volume of air leaving the room. In windless warm weather, air exchange weakens.

Calculation of the amount of air

1. Number of supply valves.
2. The capacity of the inlet valves (because it may vary depending on the model).

Below are the established norms from various regulatory documents:

1. ABOK - standards for technical materials for heating, ventilation, air conditioning, heat and cold supply, microclimate of buildings.
2. SNiP (short for “building norms and rules”) is a system of regulatory documents adopted back in the USSR that standardizes the requirements for various buildings.

Air exchange rates for residential buildings are given in ABOK-1-2002. This document contains the following requirements:

room	Amount of air, m³/h for 1 person
Living room	3 for every 1 m² (if the room area is less than 20 m²)
30 (average standard for 1 adult resident)
bathroom	50 if the bathroom is combined
25 - separately for bath and toilet
Storage room, wardrobe	Multiplicity - 1 volume per hour
Kitchen	90 - if the stove is gas
60 - if the stove is electric

Now we give an excerpt from the norms from SNiP. Documents used:

• SP 55.13330.2011, to SNiP 31-02-2001 "Single-apartment residential buildings";
• SP 60.13330.2012 to SNiP 41-01-2003 "Heating, ventilation and air conditioning";
• SP 54.13330.2011 to SNiP 31-01-2003 "Multi-apartment residential buildings".

The rules are:

room	Minimum inflow	Minimum extract
Residential, with permanent presence of people	Not less than 1 volume per hour	— (not standardized, must provide the specified inflow)
Residential area less than 20 m²	3 m³/h for every 1 m², for 1 person	—
Living space that is not in use	0.2 volumes per hour	—
Kitchen with electric stove	—	60 m³/h
Kitchen with gas stove	Single exchange + 100 m³/h	—
A room with a solid fuel boiler / furnace	Single exchange + 100 m³/h	—
Bathroom (bathroom, toilet)	—	25 m³/h
home gym	80 m³/h	—
home sauna		10 m³/h

As you can see, some rules are partially different from each other. Therefore, when designing a system, it is better to choose a larger indicator, and in general - to plan performance with a margin.

In fact, these same requirements apply not only to natural systems - they are the same for forced ventilation.

Main functions

The main function of natural ventilation is to ensure the supply of fresh air from outside and the elimination of polluted dust, excessive moisture and harmful vapors from the exhaust air inside the room.

The main components of a favorable quality of life for a person: the temperature and humidity of the air comply with sanitary and hygienic standards, the absence of carbon dioxide and other harmful gases in a residential or industrial premises, the air flow throughout the room is optimally distributed without creating drafts.

To ensure a comfortable air environment, a wall vent valve is used, which is a technological channel made of plastic or metal. The valve is mounted in walls or window openings and creates a natural flow of air due to the pressure drop between cool outdoor (more dense) and warm indoor air. The movement of air masses is carried out due to the operation of the hood or the presence of ventilation ducts.

Natural ventilation device

To make a ventilation device that works on the gravitational principle, you need to use some of the elements from the list below:

1. Air access can be provided through cracks and leaky enclosing structures. In non-residential premises, holes, dormer windows and air ducts are specially made for this.
2. Windows in micro-slit or conventional ventilation mode and open vents provide fresh air.
3. Wall or window inlet valves allow air to enter the room when the sealed windows are closed.
4. Sometimes a duct system is laid for this purpose.
5. Ventilation shafts and channels are equipped in multi-apartment and private houses to remove stagnant air from the premises.
6. If the house has a fireplace or stove, then the chimney can simultaneously remove smoke and used air masses from the room.
7. Deflectors allow you to increase the draft in the exhaust pipe.
8. Ventilation grilles close the openings of the ventilation ducts in the room. There are gratings that are mounted on the street. They protect the canal from debris, precipitation, insects, rodents and birds.
9. Anemostats are special gratings that differ from the traditional version in appearance and principle of operation.
10. Sometimes for ventilation, overflow valves are installed in the door leaf. Instead, the same function can be performed by a gap under the door.
11. The non-return damper is mounted on the air ducts in order to protect against back draft.

Wall inlets

Wall valves allow air to pass through, but protect well from street noise. They eliminate high humidity and stuffiness in the room. There is a damper to regulate the air flow. After the arrival of cold air masses, they mix with warm ones and provide a comfortable temperature in the house.

Wall valves are installed at a distance of 1.5-2 m from the floor. At least 30 cm recede from the slope of the window opening, otherwise the wall will freeze. They can also be mounted under the windowsill near the battery, so that the cold air from the street is immediately heated.

Valves for windows

The supply valves on the windows protect the structures from fogging and allow ventilation of the premises. There are several varieties of window valves: some are installed without drilling the frame or sash, others require drilling holes, but are more efficient. There are also handle valves, they can be equipped with strainers.

ventilation ducts

Ventilation channels in the wall of the house are made in the process of its construction. The standard size of ventilation ducts is 140x140 mm. Channels must be made in the bathroom, in the bathroom and in the kitchen. Moreover, in an apartment building, separate channels go from each apartment. It is forbidden to make one ventilation duct from several rooms.

Hoods

Deflectors, louvres, draft amplifiers and check valves are installed on ventilation ducts and air ducts in order to increase the efficiency of the system and protect against the following undesirable phenomena:

• overturning thrust;
• low ventilation efficiency;
• blowing out heating equipment;
• debris entering the ducts.

Responsibility in case of violation of the transfer rules

Due to low literacy or unwillingness to spend money on the redevelopment procedure, the owners of the premises often change the design on their own, moving the grate or drilling the ventilation duct.

But in this case, it should be understood that if such a redevelopment is discovered, you will have to “reap the benefits” in the form of associated risks and responsibility for what you have done.

And the following may happen:

• redevelopment will not affect the efficiency of the ventilation system;
• redevelopment will reduce the performance of the ventilation system and this will be revealed.

Since any of these options can significantly affect the comfort of living, financial stability, you should familiarize yourself with them in more detail.

You need to be aware that even when the redevelopment did not lead to a decrease in the efficiency of the ventilation system, but neighbors, representatives of the management company, housing inspections revealed the presence of changes, they have the right to demand an explanation of the situation. For example, to demand to provide documents indicating that the work performed is safe and will not lead to a decrease in living standards. And this will have to be taken into account.

But you must remember that everything can change for the worse at any moment.

For example, old neighbors who did not attach importance or did not want to make a fuss over deteriorating living conditions can sell their homes. And new tenants, having identified the problem, will immediately contact the housing inspectorate.

It happens that the redevelopment of ventilation in the kitchen itself will lead to minor changes, but one of the neighbors also decides to improve the ergonomics of their apartment at the expense of common house property. Which, in aggregate, will lead to a deterioration in the living conditions of all users of the ventilation system.

Problems for the owners of the premises may also begin during the visit of gas workers, representatives of the management company, who may notice illegal redevelopment.

And in any of these cases, you will have to bear responsibility. So, when it comes to the housing inspection, a fine will be immediately issued, the amount of which will be 2-2.5 thousand rubles. Few? Do not rush to rejoice, as this is a punishment for the very illegal redevelopment. And you will also have to eliminate its consequences, which the representatives of the housing sector will immediately demand to do.

Unauthorized intervention in the design of the ventilation system can be detected at any time. As a result, the violator will have to legalize changes in the design of ventilation and restore the design of the ventilation system

Moreover, it’s just not possible to move the vent to the old place, not knowing whether it can be done - you will have to find out this moment initially. Why do you have to contact the organization that made the system project. And it will definitely be expensive.

The photo shows climbers installing a separate ventilation duct. And this is not accidental, since it is this method that allows you to solve all the problems with the layout and ensure the efficiency of air exchange.

But redevelopment can disrupt air exchange, for example, the smell of your dishes being prepared will penetrate to other residents.

When neighbors detect that air circulation is impaired or stopped altogether, they may make angry demands to fix the problem. They should not be ignored, as they are legal.

And, if the neighbors don't get their way, they can move to more aggressive methods, both legal and not.

If redevelopment is expected to reduce the performance of the ventilation system, the duct should be extended. That will significantly increase traction. And most importantly, the housing inspectorate and neighbors will only welcome such methods of changing the design of the system.

Legal methods of dealing with violations include appeals:

• to the management company;
• to the housing inspectorate;
• to court.

And then it will be as described in the previous paragraph. That is, they will immediately issue a fine, then they will demand that the ventilation system be restored to working order. If the requirements are ignored, the premises will be sold.

Arrangement of natural ventilation

For the device of natural ventilation in a private house with your own hands, it is necessary, first of all, to calculate the ventilation system, made on the basis of such data as the volume of air in the room and the number of people living in it. Before installing a ventilation system, it is also worth considering devices that burn oxygen and emit harmful substances.

Installation of both natural and mechanical ventilation is carried out in seven stages:

1. Calculation of the volume of air exchange (determination of the required amount of incoming air masses that meet sanitary requirements).
2. Determining the dimensions of the ducts.
3. Choice of ventilation system (natural or mechanical).The decision is made after a thorough analysis of the parameters of the premises and the environment.
4. Drawing up a scheme of ventilation ducts.
5. Determining the location of ventilation equipment.
6. The choice of places for the intake and output of air masses.
7. Installation of the ventilation system.

Design diagram of ventilation ducts

To build natural ventilation in a cottage with your own hands, it is not necessary to have professional skills. You just need to study some points of installation. One of them is laying in the bearing wall of an exhaust duct with a diameter of 14 cm, with a masonry thickness of one and a half bricks. This condition is necessary to prevent the effect of reverse thrust. Further, from the central channel, a horizontal wiring is laid through the rooms, the diameter of which is 10 cm. To ensure sufficient traction, the exhaust pipe is made higher than the ridge.

The supply of fresh air can be carried out through the inlet window valve installed in the metal-plastic windows by the manufacturer. The valve is an adjustable slot at the top of the window. This method is considered if it is necessary to replace old or install new metal-plastic window blocks.

If the windows are already installed, natural ventilation in a private house can be provided by an inlet wall valve. A through hole is made in the wall and a round pipe is inserted, equipped with gratings on both sides. From the inside, the valve opens and closes with an adjustable grate. In order not to spoil the interior of the room, the valve installed near the window is covered with a curtain. To warm up the air coming from the street in winter, the supply valve can be installed directly behind the heating radiator.

Example of installing an inlet valve

At the request of the homeowner, supply valves are equipped with sensors and filtration systems. They are installed, as a rule, in the hall, bedrooms, offices. Exhaust channels are made in household rooms. Thus, the correct direction of movement of air masses is observed. If a sufficient supply of fresh air requires the installation of a large number of supply valves, it would be more appropriate to opt for mechanical ventilation.

Ventilation system of a two-story house - Optimization of ventilation

When designing air circulation systems, care must be taken to install specialized equipment:

1. At the entrance to the ventilation shaft, install an automatic valve, which will contain a humidity sensor, which will ensure savings in the operation of the system. When the humidity in the room increases, the valve will open wider, which will improve draft.
2. In all residential premises, valves equipped with outdoor temperature sensors should be located. In this case, you can level the flow of cold air, which will maintain the necessary temperature balance.
3. For free air circulation between rooms, overflow holes with an area of ​​at least 200 sq.cm should be installed.