1. How does a Passive House work?

TRANSCRIPT

Whether we are already feeling the effects of climate change personally or seeing it more and more in the news, let‘s take action to improve our future! The building sector represents 1/3 of CO₂ emissions so there is a big potential for improvement. But how to get started?

Let‘s keep it simple with passive strategies! Take this coffee machine and thermos flask: The coffee machine needs to be actively kept warm, because it is losing a lot of energy to the outside. Meanwhile the thermos flask is passively keeping the heat inside thanks to its high quality envelope. Now would these principles also work for a house?

Just follow the 5 Passive House Principles! First, an excellent continuous insulation layer to keep the heat inside. This insulation will be interrupted by windows, but thanks to their low heat transfer coefficient value and insulated frames they will keep the heat inside. What is more, they will allow free solar gains in winter. While in summer, appropriate shading will keep heat loads outside the building. One continuous airtight envelope is also needed to avoid air leakages and thus heat leakage and moisture problems. It is also important for a passive house to be thermal bridge free. The insulation layer should be continuous and provide a uniform thermal resistance. Moreover, a passive house needs an efficient ventilation system with heat and/or humidity recovery depending on the climate. The cold outdoor air is warmed up by the hot extract air thus reducing heat losses. And in the summer the whole arrangement also keeps the heat out!

So that is how we get a building that can be heated or cooled solely via the fresh air from a ventilation system. That is to say a comfortable building that consumes so little energy, that it can easily be supplied with renewable energy. So forget about the big boiler and air-conditioner, and move on to the next video to learn more about the benefits of Passive Houses!