Insulation
When talking about Passive House most people instinctively know that there is more insulation than a code-built home. The result of insulating to Passive House levels is a building with improved energy efficiency, durability, soundproofing and reduced heat loss.
When discussing insulation, we tend to refer to things called the “building envelope” or the “thermal envelope”. The building envelope is what separates the interior of the home form the exterior, things like walls, roofs, and floors. It is the building envelope that we want to effectively insulate to keep the interior at a constant and healthy temperature all year round.
A Passive House improves the performance and health of the home by super-insulating the building envelope to minimise heat loss. It is not just about having lots of insulation but locating and installing it effectively. Insulation works most effectively when it is continuous and wraps around the building without any interruption from more conductive materials like steel or timber.
It is best to think of insulation like a puffer jacket on a cold day. Having a continuous layer of duck-down insulation keeps you nice and warm. But if you’re not wearing any gloves, your hands are a thermal bridge and still feel the cold.
The puffer jacket analogy can be applied to a Passive House, where we aim to reduce thermal bridges by having a continuous layer of insulation wrapped around the whole building. This has led to the increased used of “Warm roofs” in many buildings and the slow but growing adoption of exterior insulation, where the insulation is placed on the outside of the wall structure “outsulation”. This creates a continuous layer of insulation around the entire home, following the “Perfect Wall” concept by Joseph Lstiburek.
It is also important to balance the amount and location of insulation in the building, as too much insulation can lead to overheating during the summer months. All of this is thermally modelled to ensure you have a comfortable home in both summer and winter.
