Using Windows for Ventilation

The first way we can invite natural ventilation in is one of the oldest methods of all - windows. We want to locate windows on opposite walls to facilitate natural cross-ventilation. We want to make sure that every room has a place for air to come in and a place across the room for air to move out. In climates with daytime breezes (and if you use the landscape techniques we offer here you will have those), open the bottom half of double-hung or awning windows on the side of the house that the breeze is coming from and then the high half of double hung or high awning windows on the opposite side of the home. This will encourage cross-ventilation.

If you have casement windows, which open vertically, you can use those to capture the wind in the evenings. Just open those that open toward the wind and also those that face in the direction the wind is traveling. If they do not open in the right directions, keep them closed, as they will invite warm air in and actually make it hotter inside!

One of the great things about living in a two-story or clerestory structure is that you can use the extra shade provided on the north side of your home and your basement and stairways to create a form of natural air movement called stack-effect, which can be effective for air circulation and cooling. This technique works by capturing the coolest, heaviest, air on the north side of the house and encouraging it to move through the house and take the overheated air with it. To use this technique, simply open the lowest floor’s north windows, and if you have double-hung windows, open the bottom sash. Then, open the doors and head upstairs to open the windows on the highest story on the south side of the home, or in the direction the wind is traveling to. If you have double hung windows, open the top sash on the upper floor. You can also open your fireplace damper for a similar effect.

In all cases, the windows the air will escape from (preferably a high window on the side the wind is GOING) should be open as wide, or wider, than the window air is coming INTO.

If a room is overheating, open the high part of the windows to let out the hot air!

Make this work for you! In hot and temperate climates, with cooler nights than days, close and lock your windows during the day to keep the cooler night air IN, and then open your windows in the evenings to allow the cooler evening air in to cool down the house again. Locking your windows is not just secure – it seals leaks!