Minergie = dry air? Why the indoor climate in energy-efficient homes needs special attention

Find out in this article

• Humidity in passive and Minergie homes
• Tips against dry air in energy-efficient buildings
• Ventilation challenges in energy-efficient buildings  
• The importance of humidifiers in Minergie buildings
• Combination of air purifier and humidifier for an optimal indoor climate

Humidity in passive and Minergie buildings

Relative humidity indicates the proportion of water vapour in the air. The range between 40 and 60 per cent relative humidity creates an optimum indoor climate. In Minergie buildings, fresh air is brought in almost exclusively via the ventilation system. This ensures a continuous and controlled exchange of air. Just as if the windows were open all day, only much more efficiently and evenly. The moisture created in the room, for example with cooking or showering, is constantly transported outside. 

Especially in winter, the air usually becomes very dry as a result, because cold outside air contains little moisture anyway and dries out even more when heated indoors. Opening windows may bring in fresh air for a short time, but it does not solve the problem of dry air – on the contrary. The cold outside air contains little moisture in winter and valuable heat escapes with the open window.

Tips against dry air in energy-efficient buildings

Excessively dry air can cause a whole range of problems. You can find out what the effects on the body are here. Ventilation should be reduced to a minimum. Fresh air is still supplied, but not in such large quantities that the entire room air is completely exchanged several times a day.

In addition, the humidity in passive and Minergie homes should be checked with a hygrometer. If it is too low (below 40 per cent), it may help not to overheat the rooms. This is because the relative humidity in heated rooms drops further as the room temperature rises. 

If, despite reduced ventilation and temperature regulation, the humidity in a room remains below 40 per cent for several days, a humidifier helps to create a healthy indoor climate. Thanks to the humidifier, the humidity remains constant at a comfortable level.

Ventilation challenges in energy-efficient buildings

Ventilation concepts in passive and Minergie houses are based on a controlled, energy-efficient supply of fresh air. Stale air is extracted via fans and filtered outside air is supplied at the same time. If the ventilation system includes comfort ventilation, an active heat recovery system ensures that the temperature of the supplied air is maintained without major energy loss. The heat from the exhaust air is used to preheat the supply air. 

Although the ventilation systems on the market are technically mature and reliable, Minergie ventilation also has disadvantages. This is because very few systems take humidity into account. Although fresh air is supplied, the humidity is transported outside with the extracted indoor air and not replaced. The result is dry to very dry air. This not only has a negative effect on the quality of living and the furniture, but also on well-being. Find out about the effects of dry indoor air on the body here.

The importance of humidifiers in Minergie buildings

Humidifiers specifically improve the indoor climate. They add moisture to the room air until an optimum level is reached. Devices with an integrated hygrostat can be programmed so that they switch off automatically when the target humidity level is reached. If the current humidity falls below the desired level, these devices automatically switch humidification back on. 

There are different types of humidifiers: vaporisers, ultrasonic nebulisers, evaporators and air washers. You can find more information about the systems in the overview of our humidifiers. 

In Minergie buildings with controlled ventilation, double the room size should always be calculated when selecting the humidifier. The reason for this is the continuous exchange of air: cold or dry outside air is warmed up and fed inside. For example, if the room size is 25 m², a humidifier for Minergie buildings should be recommended for rooms of at least 50 m² in size.

Combination of air purifier and humidifier for an optimum indoor climate

In the winter months, the combination of air purification and humidification ensures a much more pleasant indoor climate.

2-in-1 appliances that do both at the same time are convenient and make everyday life easier. For residents, this not only means less dry skin, but also an overall better living experience. The mucous membranes remain better moisturised, which reduces the risk of colds. The eyes do not dry out as quickly and feel less irritated. At the same time, dust, pollen, animal hair and other particles are filtered out of the air, noticeably alleviating allergies. Unpleasant odours are reduced, making rooms fresher and more inviting. 

To find the optimum solution for your own living situation, our team will be happy to advise you. If you have any questions about ventilation systems in Minergie buildings, we recommend consulting a specialist.

Would you like to find out more about how a humidifier can help you feel better or what different humidifier systems are available? You can find more information on our information page about humidifying the air.

More about humidifying the air

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