Supply air and exhaust air in every room - does that make sense?

Efficient living space ventilation is crucial for a healthy and pleasant indoor climate in your home. It enables the continuous exchange of stale air with fresh air and helps to remove odors, pollutants and excess moisture.

In this guide you will learn more about the various aspects of living space ventilation, in particular whether it makes sense to install supply and exhaust air valves in every room.

The essentials in brief:

There are two main types of residential ventilation systems: decentralized and centralized systems. The choice between these two depends on the structural conditions of your home and your personal preferences.

Decentralized living room ventilation:

Decentralized ventilation systems are generally easier to install and require fewer structural changes. They consist of individual ventilation devices that are placed in different rooms.

These devices can control air supply and exhaust in a room without the need for a complex duct system.

A major advantage of decentralized systems is that they enable targeted control of air flows in each room. This means you can customize the air quality in bedrooms, living rooms, kitchens and bathrooms.

For example, if you are cooking in the kitchen and steam and odors arise, the ventilation unit can automatically exhaust more air in that room while keeping the bedrooms quiet.

Central living room ventilation:

Central ventilation systems are typically found in larger homes or buildings with a more complex layout.

They use a network of air ducts to distribute air to different rooms. These systems can be efficient if properly sized and maintained.

The challenge with centralized systems is ensuring that airflows are balanced in each room.

This requires careful planning and, if necessary, the use of throttles or valves to adjust the air supply in individual rooms.

Supply air and exhaust air in every room: sense or nonsense?

The question of whether both supply and exhaust air valves should be installed in every room depends on various factors. Here are some considerations:

1. Use of space: Rooms such as kitchens, bathrooms and utility rooms typically generate more moisture and pollutants than bedrooms or living rooms. In these rooms, installing exhaust vents is particularly important to prevent moisture problems and mold growth.
2. Individuality: Decentralized ventilation systems offer the flexibility to individually adjust the ventilation in each room. This can be beneficial in households with different needs and preferences.
3. Costs and effort: Installing supply and exhaust valves in every room can be costly, especially with centralized systems. It is important to weigh the benefits against the costs and ensure that the system is operating efficiently.
4. Sizing: The correct dimensioning of the ventilation system is crucial. A professional can help you find the best solution for your home.

In many cases it makes sense to install a combination of supply and exhaust air valves in certain rooms, while one-sided ventilation is sufficient in other rooms. Proper planning and sizing is crucial to ensuring an efficient and comfortable indoor climate.

Fresh air supply and air removal in harmony

Controlled home ventilation is one of the most effective measures to maintain air quality in your home.

It works on the principle that fresh air is sucked in from outside, heated by a heat exchanger and then blown into the living spaces. At the same time, used air is extracted and also heated before leaving the house.

This process not only ensures a steady supply of clean air, but also helps save energy by recovering the heat from the extracted air.

Advantages and disadvantages of supply air and exhaust air in every room:

aspect	Supply air in every room	Exhaust air in every room
Advantages	- Individual room temperature control possible	- Individual room temperature control possible
	- Targeted supply of fresh air to every room	- Efficient removal of pollutants from every room
	- Good control over air quality and humidity	- Reduced odor and humidity in any room
	- Potentially more efficient ventilation in terms of air changes	- Lower noise transmission between rooms
	- Suitable for allergy-friendly solutions	- Prevents the penetration of unwanted odors
Disadvantages	- Higher installation and maintenance costs	- Higher installation and maintenance costs
	- More complex control and maintenance required	- Additional installation effort for exhaust air ducts
	- Higher requirements for the ventilation system	- Reduced air exchange between rooms
	- Limited flexibility in space use	- Potentially increased energy costs for air treatment
	- Possible noise transmission through the ventilation system	- Potential noise transmission through exhaust valves

The intelligent room equipment: Not every room needs a supply air valve and an exhaust air valve

One of the most common questions that arise when planning controlled home ventilation is whether both a supply air valve and an exhaust air valve are required in each room.

The answer to this is not always a clear yes or no, but depends on various factors.

Room function and use:

Not all rooms in your home have the same function or are used in the same way.

A living room, a bedroom and a children's room have different air quality requirements. In living rooms and bedrooms, where people spend long periods of time, a continuous supply of fresh air is important.

Supply air valves are essential here. Damp rooms such as the kitchen or bathroom, on the other hand, require efficient air extraction to remove moisture and odors. Exhaust air valves are very important here.

Energy efficiency and sizing:

While installing supply and exhaust valves in every room can provide maximum control over airflows, it also increases installation effort and cost.

In addition, the ventilation systems must be appropriately sized to meet the needs of each room. In many cases it is more economical and efficient to blow in the supply air into the living rooms and let the air flow into the damp rooms via the hallway or other paths.

This overflow occurs under the doors or through special sound-insulated overflow openings.

Comfort and health:

Indoor air quality has a direct impact on your well-being and health. In rooms where you spend a lot of time, such as bedrooms and living rooms, good ventilation is essential to ensure fresh air and sufficient oxygen.

In damp rooms, preventing mold formation through efficient air removal is very important. The right balance between supply air and exhaust air is crucial to creating a healthy and comfortable indoor climate.

The standard solution: ventilation across rooms

The standard design of controlled residential ventilation stipulates that the supply air is blown into the living spaces and the exhaust air is extracted into the damp rooms.

This allows for efficient airflow throughout the home and ensures that the system does not need to be oversized. The flow between the rooms takes place under the doors or through special ventilation openings.

Common practice: cross-room ventilation in use

Optimal air flow for every room

The application of controlled residential ventilation in practice often follows a tried and tested pattern: supply air is blown into living rooms and bedrooms, while exhaust air is extracted into damp rooms.

This approach ensures optimal air quality in the rooms and prevents the formation of mold and moisture problems.

A case study with two rooms: bedroom and bathroom

To explain this principle in more detail, let's look at a simple example with two rooms in a house: a bedroom used as a living room and a bathroom as a wet room.

The air flows in these rooms must be carefully planned to ensure good air quality.

Bedroom (living room):

A continuous supply of fresh air is important in the bedroom as it is a room where people spend long periods of time. Therefore, supply air is blown in here to ensure that there is always enough oxygen.

The amount of supply air is dimensioned according to the requirements of the room. In this example we assume a fresh air volume flow of 35 m³/h.

Bathroom (wet room):

The bathroom is a wet room where moisture and odors must be removed quickly to prevent mold from forming.

For this reason, exhaust air is removed here. We also set an exhaust air volume of 35 m³/h to ensure that the moisture is effectively removed.

The clever solution: air flow across rooms

The optimal solution in this case is to allow the supply air that is blown in the bedroom to flow across the hallway and then extract it as exhaust air in the bathroom.

This is the standard procedure in residential ventilation and has several advantages.

Efficient use of air flows:

With this method, the air that has already been heated in the bedroom is used in the hallway to ensure the supply of fresh air to the bathroom.

This leads to efficient use of air flows and prevents unnecessary heat loss.

Cost and space saving:

Installing supply and exhaust air valves in every room can significantly increase installation effort and costs.

In addition, the ventilation systems would have to be larger in size to meet the needs of each room. The cross-room solution not only saves space, but also energy and costs.

Healthy indoor climate:

The right balance between supply air and exhaust air is crucial for a healthy and comfortable indoor climate.

The air flow across rooms ensures that fresh air is continuously supplied and used air is effectively removed.

Challenges with individual room temperature

Room temperature requirements

One of the aspects that must be taken into account when planning supply and exhaust air valves in each room is the individual room temperature.

If supply air and exhaust air are connected in every room, it becomes more difficult to achieve different room temperatures.

This is because the air flows in each room must be controlled separately to achieve the desired temperature.

The effort required for installation

Installing supply and exhaust air valves in every room is often considered costly and labor intensive. Each room requires special planning and adjustments to make the ventilation system efficient.

This means additional costs for the valves themselves, the channels and the control systems. Additionally, regular maintenance and calibration of these valves requires additional effort.

The role of the overflowers

An alternative solution to ensure air exchange between rooms is to install air vents between rooms.

These transfer valves allow air to flow from one room to another without the need for separate supply and exhaust valves in each room.

This can be a cheaper and easier option, especially in residential buildings.

The advantages of the overflow solution

Efficient air exchange:

Although the air exchange between rooms through transfer valves is lower than with separate valves, it is often enough to maintain a healthy indoor climate.

The slower air movement allows rooms to better maintain their individual temperatures as less heat is lost.

Cost efficiency:

Installing transfer valves is usually more cost-effective than installing supply and exhaust air valves in every room.

This can significantly reduce the overall cost of a ventilation system, especially in larger buildings.

Less maintenance:

Transfer valves typically require less maintenance and calibration than individual valves in each room.

This can reduce the operating costs of the system and reduce maintenance requirements.

Final thoughts

The decision whether to install supply and exhaust air valves in each room or whether to use transfer valves depends on various factors, including the specific needs of the building and budget.

Both approaches have their advantages and disadvantages, and the right choice depends on individual circumstances. It is advisable to seek advice from experts in the field of ventilation technology to find the optimal solution for your project.

Frequently asked questions about supply air and exhaust air in every room: