Ventilation unit filter replacement intervals can vary a lot. In some homes, the filters turn dark within a few weeks. In others, they can almost be forgotten for close to a year. The difference usually comes down to outdoor air pollution, where the home is located, ventilation intensity, whether the unit is correctly sized, the filter class, installation direction and the quality of the filter itself.

This article explains why children may cough more frequently or fall ill even in seemingly clean homes – and how indoor air quality plays a key role. It covers the main contributing factors, including pollen, particulate matter (PM10, PM2.5), volatile organic compounds (VOCs), and insufficient air circulation. You’ll also find practical guidance on choosing the right filters for your situation – whether you’re dealing with allergies, pollution, or lingering odours. Learn how to reduce exposure to airborne pollutants and improve the air quality in your home.

As spring arrives, pollen levels in the air increase and can trigger allergies and hay fever. An effective pollen filter for your ventilation unit helps protect indoor air quality and reduces the amount of allergens entering your home.

Ventilation pollen filters help reduce allergens indoors. Learn why choosing a more efficient pollen filter before the pollen season can help improve indoor air quality and make life easier for allergy sufferers.

Air pollution in Europe often peaks in late winter and early spring due to heating, traffic and weather conditions. This guide explains what PM10 and PM2.5 levels really mean, how to monitor air quality, which countries are most affected, and when to choose a coarse (G4), ePM10 (M5) or ePM1 (F7 / PM1) ventilation filter — especially for protection against urban pollution and smog.

During the colder months, the performance of a heat recovery ventilation unit depends strongly on the type of heat exchanger used. Rotary exchangers usually operate more continuously, but the supply air may feel cooler, meaning additional heating is sometimes needed for comfort. Plate heat exchangers, on the other hand, may switch to protective modes more quickly in low outdoor temperatures, and without a preheater, stable ventilation can become limited. In this article, we explain real-life scenarios: when reducing airflow makes sense, why filters clog faster in winter, and how to lower energy consumption while maintaining a healthy indoor climate.

In winter, outdoor air becomes very dry once it is heated indoors, and mechanical ventilation often reduces indoor relative humidity to 20–30 RH or even lower. This article explains why this happens, how different heat exchanger types (plate, condensation rotor, enthalpy, sorption) affect indoor moisture balance, and what you can do in practice. We cover smart ventilation control during cold nights, protection against excessive drying, when a humidifier is really needed, and simple ways to increase or reduce humidity naturally. You will also find an FAQ with common real-life situations and climate-specific recommendations for different countries.

Cold outdoor air and warm, humid extract air can create condensation that may freeze inside the heat exchanger. Learn what “defrost” does, why airflow balance matters, and how to reduce frequent frost cycles.

Not all ventilation unit filters are the same. Some ensure clean, healthy indoor air, while cheaper or uncertified filters can pose risks to both the ventilation system and your health. This guide explains what to look for when choosing filters — from ISO 16890 testing and hygiene standards to material safety and real filtration performance — so you can be confident you’re using a safe, certified and reliable filter.

Cold and flu season often starts indoors — not outside. While filters in your ventilation unit can’t trap viruses themselves, proper air exchange, high-efficiency filters and balanced humidity greatly reduce the risk of infection and keep your home air cleaner and healthier.

Foggy windows, high humidity or mold in homes with an AHU or MVHR system? Learn why this happens and how to fix it – from airflow adjustments to filter checks.