Get a better indoor climate with a little extra effort

Homes today are built with major focus on air tightness. This can cause challenges in terms of condensation on windows and doors. Condensation occurs when warm, moist air is cooled against a cold surface, e.g. a window. Autumn and early winter is "high season" for condensation on windows, due to cold nights and mornings combined with having the heating on. During periods of severe frost, when the temperature difference between inside and out is very large, the risk of condensation is greater. If ventilation is not carried out to a sufficient level, the mist condensates on the windows, much to the annoyance of residents.

There is one way to remove the moisture in buildings - heating and venting. Problems with condensation occur due to:

Different temperatures in neighbouring rooms.

Moisture and condensation is usually present in the coldest places, typically windows in bedrooms and wet-rooms where the temperature is lower than in other rooms.

Too little ventilation.

In the period from October to January, the need for ventilation is at its greatest, whereas people tend to reduce ventilation to keep the heat in.

The moisture that has accumulated in your home over the summer period must be vented in the autumn, if that doesn't happen the moisture will set as condensation. The problem is exacerbated by the fact that in the autumn and winter we often dry laundry etc. indoors, which only makes the need for ventilation even greater.

Poor air change.

In autumn and winter, curtains are down and blinds closed. This can cause stagnant air between the windows and curtains or blinds. The air then gets cooled down and sets as condensation on the window pane.

The combination of different room temperatures, high humidity and stagnant air provides a favourable environment for condensation. When moisture first sets as condensation droplets on the window, it is too late to ventilate it away. At this stage, take a dish cloth or paper towel and wipe the window.

We recommend that the indoor climate should have a relative humidity of no more than 40-45%. In October, it's typically 60-80%, which requires a higher level of ventilation. You can measure the humidity in your home with a hydrometer. You get the greatest effect of ventilation when the outside air is dry, typically from October and throughout the winter.

Tips

Out with the moisture
Make your home ready for the winter with an extremely thorough airing of all rooms. That means many hours where windows and doors are left wide open. Rooms must be aired so that the accumulated moisture in the building and housing materials disappears before the cold winter temperature sets in. Furthermore, you should pay particular attention to venting wet-rooms and bedrooms daily and thoroughly. These spaces are characterised by being small, damp and with poor air circulation and lower room temperatures - a favourable environment for condensation.

Check outlets (shaft)
Every autumn, check that there is an unobstructed passageway of air through wall and ceiling vents, especially in the wet rooms (bathroom and laundry room) and in living rooms where the vent is usually located in exterior walls or windows. So clear out dust, cobwebs and bird nests!

Exhaust or vents
Are there vents or outlets in every room? These will provide the best air circulation throughout the house.

Air may times per day
This applies to all living areas and especially to bedrooms and bathrooms, even if there isn't condensation on the windows. It is important to air even when it rains!

Allow air to circulate
Leave doors open between the different areas so that air can circulate freely throughout the day.

Same temperature
Raise the temperature to 20-21 degrees, and keep the same temperature in every room as far as possible.

Wet clothes deliver plenty of moisture
It is important to keep windows open if you choose to dry your clothes indoors.

Mechanical ventilation
If you have mechanical ventilation, it is important that it is set correctly in relation to your particular property and that the facility is regularly maintained according to the supplier's instructions.

New windows in an older house
Do you live in an older house where you have replaced the windows with new ones? If so, then it is natural that the windows get misted in October / November, simply because the house has become denser. Therefore you should ensure that your property has adequate ventilation openings in exterior walls and ducts in the ceiling (there should / must be at least one in each room).