Why is ventilation important?

Our houses are increasingly better insulated, which is of course good news for energy consumption, which is constantly decreasing. However, these well-insulated houses also have a risk of insufficient ventilation.

More and more contractors are providing central ventilation systems in newly built houses, but this is not always done for every room.

An example: cellars are often a forgotten place when it comes to ventilation. The result: an increase in humidity and an increased risk of condensation (which in turn can cause mould).

Morality of the story: ventilation is important to prevent moisture problems. In this article, we explain why ventilation can make a huge difference and which ventilation systems you can install - without heat loss.

Four good reasons to ventilate

Were you looking for a reason why ventilation is important? We'll give you four important reasons.

Number 1

Good air quality

The most obvious advantage of correct ventilation in the home is of course the high air quality. If the air can circulate well, the air quality in your home will automatically be the most optimal and therefore the healthiest.
Number 2

Moisture removal

An average person produces about 10 litres of water vapour in one day, which increases humidity. This includes all human and non-human activities such as breathing, showering, washing or cooking. Without proper ventilation, that moisture can do nothing but condense against cold surfaces such as walls or windows.
Number 3

No more musty smell

Everyone knows that damp, unventilated rooms can smell very musty. This is, of course, a normal consequence of the lack of air circulation. In unventilated rooms, everything smells less fresh than in ventilated rooms.
Number 4

Allergic? Then ventilation is definitely a must

Anyone with allergies or asthma knows that fresh air is extremely important. Poor air quality can exacerbate asthma and some allergies, as well as causing additional complaints such as headaches or fatigue.
Why you have to ventilate

What happens if you don't ventilate?

1. Ventilation is the only way to dissipate moist air

Moisture is produced in a house in large quantities in the order of 10 litres per person per day, depending on the number of people. These quantities can only be removed from a dwelling by means of ventilation. Especially in new homes, which in most cases are well insulated and airtight, well thought-out ventilation is crucial to prevent moisture problems with condensation and mould. In other words: controlled ventilation is necessary to keep the air clean and healthy.

2. Indoor air regularly too dry or too humid, depending on temperature

In a non-ventilated house with high insulation, the air pressure inside is almost never the same as outside. In addition, the indoor air can become either too dry or too humid, depending on the temperature differences.

A good ventilation system makes use of these pressure differences and ensures regular ventilation without heat loss:

The Belgian ventilation standard for passive houses gives as a guide a n50 value of 1 if you choose ventilation system D with heat recovery. This is a system with mechanical supply and extraction. In concrete terms, this means that the air in the house can be changed once per hour at a pressure difference of 50 Pa (Pascal) between inside and outside.

If you work with ventilation system C, in which a natural supply takes place via window grilles and mechanical extraction takes place, then the standard prescribes an n50 value of 3. So here you have three air changes per hour.

If you have a ventilation system C, airtightness is very important for good air circulation. With ventilation system D, airtightness is mainly important for heat recovery efficiency.

3. A non-ventilated house is not healthy to live in

A healthy indoor climate is not a matter of course everywhere. In houses where there is little or no ventilation, various air quality problems can arise:

  1. Recently installed building boards, building materials and adhesives can release volatile organic compounds (VOCs) into indoor air (source: Vision on Technology - VITO).
  2. Moist air can lead to condensation against cold surfaces (windows, walls)
  3. Condensation can cause mildew and affect the paintwork and plastering