As well as being a chartered architect, Tim Offer is also a certified Passive House designer in Devon.
Passivhaus, or passive house, is a simple concept designed to minimise energy use while providing a really comfortable indoor environment. It is a flexible approach that does not prescribe how to meet the baseline targets, allowing creativity and a variety of solutions. It is dependent on careful detailing and rigourous attention to getting things right on site.
A key aspect of a passive house is a reduction in the energy used to heat it. This can be reduced to such a level that the heating demand can be met by passive means – solar gains from the windows and the heat produced by the people and equipment inside it. By using high levels of insulation and carefully controlling air leakage, the building can be kept warm during cooler months and have reduced heat gains inside the building in the summer. Passivhaus buildings achieve a 75% reduction in space heating requirements, compared to standard practice for UK new build. This means that it is a great way to achieve the kind of energy savings that we should be aiming for to achieve zero carbon targets.
As well as energy efficiency, a key driver of the standard is occupant comfort. By maintaining a stable temperature, both of the air and also internal surfaces, drafts are reduced as well as the feeling of cold given by cooler surfaces such as windows and uninsulated walls. Maintaining surface temperatures also eliminates condensation and mould growth.
Alongside controlled airtightness it is essential to provide fresh air mechanically to maintain good air quality.
The main elements of a passive house are:
- excellent thermal insulation of the building envelope.
- high performance windows, with triple glazing and insulated frames
- airtight construction to eliminate drafts and ventilation heat loss
- avoidance / minimising of thermal bridges through the insulation
- a mechanical ventilation system with highly efficient heat recovery
There are a number of myths about passive house buildings. You can open windows – indeed this is an essential part of a summer cooling strategy in many passive houses. There is a great artical about passive house myths by Elrond Burrell here.
For more information about the Passivhaus standard, visit Passipedia.
Millway was designed to passive house principles, and was featured in Passive House + magazine.
If you are thinking of building a passive house in devon, please get in touch to see how we can help.