In addition to CO2 (read about its effect on the indoor environment here), humidity is another very important factor that affects the well-being and comfort of people living indoors. And it’s also where we spend a lot of time – up to 90% of the time each day, according to recent research!
Relative Humidity or RH = the ratio between the amount of water vapour in the air and the maximum possible amount of water vapour at a given temperature.
Relative humidity is given as a percentage (%) – how much moisture is in a room depending on the temperature.
This range varies based on the time of year. While in winter we should keep the humidity in the apartment between 40 – 60%, in summer the upper limit is slightly lower and the humidity should be between 40 – 55%.
Higher or lower values often lead to overall discomfort in the indoor environment and also
various health problems.
High humidity is easily recognised by dewy windows, damp walls and possibly even furniture or floors. This contributes to the formation of mould on windows, joints and room walls. Mould can then have a negative effect not only on the building elements and furnishings of the home, but also on the health of the occupants. Allergies, atopic eczema or other respiratory problems are unpleasant manifestations.
Most of the time it is not such a difficult task. In newly renovated buildings and apartments, the humidity is often higher at the beginning – but gradually the building elements that may have been damp due to the construction/renovation dry out.
The recommended method is, of course, sufficient ventilation – whether of the whole house/apartment or perhaps in the busiest bathroom, drying laundry outside and using a cooker hood. The best way is ventilation based on a humidity sensor. This monitors the air quality – the humidity in the flat/house and according to the measured data controls for example the bathroom fan or the whole air handling system.
Low humidity (below 40%) is probably even more unpleasant than high humidity. The symptoms can be:
In addition, when humidity is low (i.e. high evaporation of water), volatile organic compounds (VOCs) from furniture, carpets, etc. enter the air and are the main cause of the negative symptoms associated with indoor air pollution – you can read more about them here.
We can increase the humidity in the apartment by the opposite process. It is recommended just to dry clothes in indoor rooms, grow houseplants or put a container of water on the heater. Another solution can be a humidifier, which splits the water into microparticles and releases them into the room.