Supply Air Valve Installation — Adequate Replacement Air for Healthy Living

A supply air valve is a simple but effective solution for ensuring adequate intake air. Especially in older buildings with gravity-based ventilation or mechanical exhaust only, the replacement air supply can be insufficient. Without a supply air valve, the exhaust fan creates strong negative pressure in the dwelling.

Excessive negative pressure causes many problems:

• Uncontrolled air leakage: Replacement air comes through the building envelope unfiltered, bringing contaminants from within the structures
• Sensation of draft: Air penetrates through window and door gaps, causing cold drafts
• Moisture damage: Moisture condensation in structures can lead to mold growth over time

A supply air valve brings fresh outdoor air in a controlled and filtered manner, improving both indoor air quality and the condition of the building structures.

There are several types of supply air valves that suit different needs and structural solutions:

• Wall valve: Installed in the external wall above a window or near a radiator. The most common solution, suitable for most situations
• Window valve: Installed in the window frame or sash. Small and discreet, but airflow is limited
• Frame valve: Integrated into the window frame, eliminating the need for a separate installation hole
• Sound-attenuating valve: Equipped with sound insulation, suitable for locations near busy roads

The choice of valve depends on the external wall structure, noise environment, required airflow, and aesthetic preferences. A professional installer can recommend the right valve for your home and the optimal installation location.

Installing a supply air valve is a quick and tidy job that does not require major structural changes. The installation process proceeds as follows:

• Location selection: The optimal placement is on an external wall, preferably above a radiator, where the incoming cold air is warmed by the radiator's rising air current
• Diamond drilling: A suitable hole for the valve (typically 100 to 160 mm) is drilled cleanly and dust-free through the wall using a diamond drill
• Pipe installation: A thermally insulated sleeve pipe is installed in the hole to prevent cold bridging
• Valve mounting: The valve itself is installed and adjusted to the correct position
• Sealing and finishing: The connections on both the exterior and interior are carefully sealed

Installation typically takes 1 to 2 hours per valve. The work is carried out neatly without unnecessary mess.

The placement of supply air valves has a significant impact on ventilation performance and living comfort. Correct valve placement follows these principles:

• Living spaces: Valves are installed in bedrooms and the living room, where supply air is needed most
• Near the radiator: Placement above a radiator is ideal, as the radiator heat mixes with the incoming air and prevents the sensation of draft
• Not in the bathroom: Supply air valves are not installed in wet rooms where there is an exhaust air valve
• Correct height: A wall valve is typically installed at a height of 1.8 to 2.2 meters from the floor surface

The number of valves depends on the size of the dwelling and the type of ventilation system. As a rule of thumb, each living space that does not have a supply air duct needs its own supply air valve. A professional installer determines the valve requirements based on an overall assessment.

A supply air valve is an affordable way to improve a dwelling's ventilation and indoor air quality. Costs consist of the valve device and installation work:

• Basic valve installed: 100 to 250 euros per valve
• Sound-attenuating valve: 200 to 400 euros per valve installed
• Window valve: 50 to 150 euros per valve installed

The investment pays for itself through improved indoor air, reduced moisture stress on structures, and lower heating costs. Controlled replacement air reduces uncontrolled air leakage, so energy is not wasted on heating unfiltered cold air.

Installing supply air valves is also an excellent measure before increasing the power of a kitchen range hood or bathroom exhaust fan, as effective air extraction always requires an adequate supply of replacement air.