Windows are a major source of heat loss, so Passive House standards typically require triple glazing and uPVC frames to eliminate thermal bridges. Timber looks better but expands seasonally and costs more; thermally broken aluminium is pricier still. uPVC offers the best value for meeting the energy performance criteria.
One of the biggest sources of heat loss and heat gain in a building is through the glass, and that's why the selection of glass for a Passive House is absolutely critical. The bare minimum in Passive House standard is double glazing, but more often than not, you'll need triple glazing to achieve the Passive House requirements. One of the things that also combines really closely glazing is eliminating thermal bridges. And you can see here we've built with uPVC frames, and the reason for using uPVC frames is that the plastic eliminates the thermal bridging of the cold or the heat from outside to inside. And putting this together in combination with high-quality glazing is what will get you over the line with a Passive House. One of the reasons we use uPVC windows and doors is that they represent the best cost for value proposition in the marketplace at the moment. You can also use thermally broken aluminium or timber, and they each have their drawbacks. One of the things with thermally broken aluminium is that you're still using aluminium, which is a fantastic conductor, and they also generally cost more than uPVC frames. If you're looking at timber frames, they are very sustainable and they're beautiful to look at when they're finished. However, one of the One of the hardest things about wooden frames is that they move around seasonally. Timber expands and contracts, and when you're trying to keep a good airtight seal between a window sash and the frame, if the seals are able to become loose during summer, then you'll get greater air leakage, and then the house won't perform the way that it's meant to. The other thing is that timber costs more. If you want to know more about building a Passive House, download our guide to the 5 key skills of a Passive House builder. All right, very good.
