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VALLOX TSK
BASICS OF VENTILATION
3
THREE QUESTIONS ABOUT VENTILATION
Why is air replaced in dwellings?
Good ventilation promotes healthy living for both residents and the building.
Air in a dwelling needs to
be replaced in order to remove humidity brought about by living as well as impurities
emanating from structures and human bodies. Impurities of indoor air include carbon dioxide,
formaldehyde, radon and other gases as well as dust.
Mechanical ventilation is needed in order to be able to adjust air circulation as needed by
the residents. In a tightly sealed house, air does not circulate sufficiently by natural means.
Even in a poorly sealed house air is only replaced because of differences between indoor
and outdoor air temperatures, or because of winds. This means that ventilation is dependent
on weather conditions and cannot be regulated.
It is especially important that humidity and carbon dioxide content of indoor air stay at a
healthy level. Recommended humidity content of good indoor air is approximately 45%.
Humidity content is lower in winter and higher in summer and autumn. Dust mites thrive in
indoor air if humidity exceeds 50%, and if humidity stays at over 60% for a long time in
winter, water will condense in the cold structures of the house and mould will start to form.
The recommended maximum carbon dioxide content in good indoor air is circa 1,000 ppm.
What are the characteristics of adequate ventilation?
• Indoor air stays fresh in all the rooms of the dwelling, also in bedrooms during night.
Without adequate ventilation
, carbon dioxide content tends to rise high especially in
bedrooms.
• The bathroom and sauna get dry quickly.
• During the heating season, the windows and other outer wall structures remain dry.
• Humidity in indoor air is not condensed in the ventilation ducts.
• Air is fresh in the toilet as well.
How much air is replaced?
For air to be clean to breathe, it has to be replaced with outdoor air
once in two hours.
In a
new and a renovated house, air needs to be circulated continually, at least once an hour,
during the first year in order to remove harmful gases and structural humidity. In buildings
that are more than a year old and dry, ventilation can be regulated as needed. Ventilation
is boosted during for instance a sauna bath, clothes washing and cooking, and reduced
during very cold periods or when there is nobody at home.
Window ventilation
Dwelling-specific supply / extract air circulation by no means prevents you from opening
windows and the door to the balcony or airing through them. In window or door ventilation,
however, attention needs to be paid to the following factors:
1. During the heating season window ventilation consumes, uncontrollably, a considerable
amount of energy.
2. An open window lets in dusty and dirty air.
3. An open window also lets in noise pollution.
4. During summer, door / window ventilation may bring in air that is warmer than that in
the dwelling.
SEASONAL CALENDAR
Spring:
• Wash or replace the coarse filter and replace
the fine filter if needed.
• Clean the fan blades and the post-heating
unit if needed.
• Check that summer ventilation is in operation.
When this is the case, extract air does not heat air
coming from the outside.
NOTE!
For further details, see inner pages.
Autumn:
• Wash or replace the coarse filter and replace the
fine filter if needed.
• Check that the heat recovery cell is clean.
• Check that the condensing water outlet is not
clogged.
• Switch summer ventilation off.
