22 Jul Why should your next project be Passivhaus?
Passivhaus buildings provide a high level of occupant comfort, whilst using very little energy for heating and cooling. They are built with meticulous attention to detail, rigorous design and construction according to principles developed by the Passivhaus Institute in Germany, and can be certified through an exacting quality assurance process. They generally need 90% less energy for heating and hot water than standard buildings and have very low running costs.
Passivhaus standard takes a ‘fabric first’ approach, a sustainable architecture should not be reliant on technological add-ons such as solar panels and wind turbines alone. If the fabric of a building is not sufficient, then any energy gains generated by such technologies will merely offset the losses of the building’s overall inefficiencies. Given limited financial resources, it is far better to invest in a more efficient fabric and add the ‘eco-bling’ later on.
The following are key characteristics of Passivhaus buildings:
- Super insulation – lowering energy bills and improving the comfort for occupants, 300mm insulation is typical in walls
- Excellent mechanical ventilation with up to 94% of the heat recovered – provide the ventilation for the building providing high levels of warm, fresh air
- Triple glazed opening windows – designed to catch the suns warmth, lower energy use and improve the comfort for occupants
- Airtightness – reduce energy loss through draughts and increase the comfort for residents
- Solar gain – both for heating the house and using solar panels to heat hot water. Passivhaus buildings need to be designed to capture the right amount of sun throughout the year.
As a consequence of these relatively simple concepts that the building retains heat from activities such as cooking, using computers or showering, it uses this to heat the building and does not need a traditional central heating system. There are over 20,000 completed passivhaus projects, mainly in Germany and Austria.
The Passivhaus model is to invest in capital costs with excellent construction quality, in order to minimise the ongoing energy costs.
Capital costs vary, in Germany they expect Passivhaus construction to be 8% above standard costs, the examples in the UK have shown that costs can be between 5% and 20% more than 2010 standard construction costs. Getting a knowledgeable team is vital to minimising these costs and ensuring the project is completed to high standards.
The trade off with high capital costs is that the heating costs are very low, typically less than £2 per square metre per year. As this is based on ‘built in technology’ such as insulation and solar gain there are few components that need servicing or replacement. This is a key benefit to you and helps tackle increasing fuel prices whilst offering comfortable living environment. With the price of our domestic energy forecast to continue to rise over the next decade, passivhaus principles make a lot of sense.
Feedback from Passivhaus Residents
The Y Foel project in Wales is a large private house. The resident and builder, Mark, keeps an extensive blog on the experience of living in the house and updating its energy consumption. it can be found at:
The Denby Dale project is in England, its owners Geoff and Kate have been keeping an online diary at:
How we can help
We can help you design your dream house to passivhaus standards, identify funders for the project and help you through the design and construction process. Contact Matt Bridgestock for more information on 0141 551 8383