# How to ventilate rooms properly in winter A few minutes a day for fresh air, dry windows and minimal heat loss. In winter many people keep their windows closed to avoid losing heat. In modern airtight homes, however, this can have the opposite effect: the air becomes stuffy, condensation appears on the glass and moisture can start to build up around the frames. The good news is that proper ventilation takes only a few minutes a day, and the heat loss is negligible. ## Why is ventilation so important in winter? People, cooking, showers, drying laundry and even houseplants constantly add moisture to indoor air. Modern windows and doors are very airtight, so the humid air has nowhere to go. The result: - condensation on glass and frames - damp corners and exterior walls - poorer air quality, especially in bedrooms - a higher risk of mould This does not mean the windows are of poor quality. Quite the opposite – airtight windows retain heat well, which is exactly why regular ventilation becomes even more important. ## Short and intensive, not long and slow The most effective method is cross-ventilation: - Open the windows wide (ideally on opposite sides of the home to create a through-draught) - Leave them open for 5–10 minutes - Close the windows During this time the air in the room is fully replaced, while the walls, furniture and floor stay warm. That is why the room warms up again quickly once the windows are closed. ## Why keeping a window tilted for hours in winter is not the best idea A tilted window left open for hours causes two problems: ### Heat loss Cold air flows into the room continuously and the heating runs at full power. ### Cooled frame and wall The wall around the open window cools down, and condensation forms precisely on these cold surfaces. Tilt mode is useful in summer or in spring and autumn, but in winter short, intensive ventilation is more effective. ## How often should you ventilate? General recommendation: ### Living rooms 2–3 times a day. ### Bedroom Air before going to bed and in the morning. ### Kitchen and bathroom Air after every cooking session and shower. If many people live in the home or laundry is dried indoors, ventilate more often. ## Tips for reducing indoor humidity - Use a lid and the cooker hood when cooking - Open the bathroom window or switch on the fan after a shower - Dry laundry with ventilation or in a separate, well-aired room where possible - Do not cover radiators with heavy curtains or furniture - Do not place furniture tight against exterior walls, so air can circulate behind it - If possible, keep indoor humidity at around 40–60%. You can check it with a simple hygrometer ## What if condensation appears every day? Condensation on the inside of the glass is sometimes normal, especially on cold days. But if it appears regularly and does not disappear after ventilating, it is worth checking: - whether the rooms have sufficient air exchange - whether the windows offer micro-ventilation - whether the window seals and condition should be inspected - whether the condensation is visible between the panes. That is a different problem – it indicates a failed sealed unit and cannot be solved by ventilation ## Related articles Condensation on windows Window micro-ventilation Window care ## Noticing regular condensation or moisture around your windows and not sure why? Book a free consultation and we will assess whether changing your ventilation habits is enough or other solutions are worth considering. info@nordicwindowsolutions.com · +371 22324322 Book a consultation