What is Passivhaus?
Passivhaus, also known as ‘Passive House’, is a design approach which aims to achieve optimised energy efficiency and a high level of comfort.
Passivhaus buildings are designed to use significantly less energy than conventional buildings. They also provide a healthy and comfortable home environment all year round. A rigorous system of quality control on site ensures that the completed building will perform as intended, avoiding the so-called “performance gap”.
The Passivhaus design approach is based on the following key principles:
- An optimised building form which can also make the building cost effective to build
- A thick layer of insulation to the floor, walls and roof providing a cosy winter jacket for the building
- Ensuring that the insulation is continuous, without any gaps – known as thermal bridge free construction
- A very high level of airtightness to reduce unwanted heat loss and also to prevent discomfort due to draughts
- High performance triple glazed windows which retain heat in winter while allowing solar gain to help heat the building; the glazing is also carefully designed to prevent overheating during the summer months
- Mechanical ventilation with heat recovery which provides a constant reliable supply of fresh air, even during winter
The design is developed using specialist software to accurately predict the building’s energy consumption. A certified Passivhaus can typically be heated in the coldest winter conditions using only 10 watts per square metre of floor area – that’s equivalent to an old fashioned 100W light bulb or a couple of candles per room!
There’s no point designing an energy efficient home unless this can be achieved in reality, which is why Passivhaus also provides a rigorous quality control system to ensure an excellent level of build quality is achieved on site. Buildings designed and constructed according to this methodology have consistently been shown to perform as well as predicted.
Passivhaus can be applied to any construction method, be it timber frame (prefabricated or “stick built” on site) or masonry cavity wall. The design approach has also been successfully applied to other building types as well as homes. The design is informed by the local climate and site conditions and the approach can be used anywhere in the world.
The Passivhaus approach can be applied to existing buildings as well as new buildings. Read more about energy efficient retrofit here.
In addition to having a wealth of experience designing energy efficient homes, Graeme completed Certified Passivhaus Designer Training in 2022.
Applying Passivhaus principles involves consideration of energy performance from the very earliest stages of the design process. Big energy efficiency wins can be achieved by viewing such factors as siting, orientation and the shape of the building through the lens of Passivhaus at the outset of the project.
