Just Right……Fresh Air
Often when I tell people that I live in a Passivhaus they have no idea what it means. Others have some idea that it is a low carbon house, but they say they wouldn’t like to live in one as they assume it means the windows need to be continually closed and that there is no fresh air. This isn’t true at all. You can have opening windows in a Passivhaus. In fact, it’s beneficial to the function and maintenance of the house to have opening windows.
Like most people, we like to have opening windows to keep a connection to the outdoors and we like to be able to choose whether to keep the windows open or not. In this house, we have turn and tilt windows in every room (they’re much easier to clean and maintain too) and full height lift and slide doors on the ground floor. The house has been designed to allow cross ventilation and includes an opening roof light in the centre of the house, which helps with the ventilation/ cooling strategy. It also lets in lots of lovely natural light. During warm periods we find that opening the windows at night to cross vent (since the external air temperature cools down at night) works very effectively and that during winter nights it is also possible to leave a window open and find the temperature of the room is stable. I remember doing this by mistake during the snowy winter we had a few years ago and when I got up in the morning being amazed at how the room was still very comfortable despite it being below zero outside!
Passivhaus homes are designed using specific local climate data and the design also takes account of the building orientation so that solar gain/ shading suits the building location and makes the building work on its own and with its occupants. We have a balcony on the first floor which provides adequate solar shading for the south facing ground floor rooms during the summer and the mono pitch roof oversails the first floor of the housing providing the same solar shading effect for the first floor rooms. This helps prevent overheating in the summer months. Interestingly, during the winter months when the sun is lower in the sky we benefit from more solar gain which warms the house nicely!
Whilst on the subject of windows, the other element that most Passivhaus homes have is triple glazed windows. So far (6 years on) the ones we have are performing really well. Going back to that comparison of a ‘normal’ house – when you stand next to a window it tends to feel cooler and your curtains tend to help keep the room warmer. In a Passivhaus with triple glazed windows, you don’t get this cooling, even right up next to the glass and they provide a great acoustic seal.
By Emma Butler