Developed in Germany in the 1990s, Passivhaus is a voluntary but rigorous quality assured standard for low energy building. With the cost of renewable energy on the rise, it is a movement that is gaining much attention throughout the UK, with standards far exceeding those of current Building Regulations.
Much of Passivhaus’ popularity comes form the fact that there are many ways to meet the criteria. Architects can use complex software called the Passive House Planning Package (PHPP) to predict the future energy demands of the home, taking into account characteristics that will affect heat loss and energy use.
The Passivhaus Standard
Achieving the Passivhaus standard in the UK will typically involve the following standards:
- Accurate design modelling using the PHPP
- High levels of insulation
- High performance with insulated frames
- Airtight building fabric
- Thermal bridge free construction
- A mechanical ventilation system with efficient heat recovery
Of course, Passivhaus homes are not homes without heating. Instead, they work to reduce the space heating requirements so that a conventional heating system is no longer required. The average target for a 160m² house is 2,400kWh of energy throughout the year. Roughly, this is a tenth of what a typical British home would use and a third of what an average ‘eco-home’ consumes.
Properties can achieve Passivhaus certification, awarded by The Passivhaus Institute. However, there are still more than 20,000 Passivhauses that are not certified, despite reaching the required standard.
How to Achieve Passivhaus In Your Home
Experts have recognised that homeowners now want to renovate their property to achieve low energy levels. Typically, this requires certain projects such as insulating the roof, external walls and internal walls to achieve air tightness. All gaps in windows and doors must be sealed so that insulation is tightly packed.
While there is no set method for achieving the Passivhaus standard, there are various ways to provide the necessary space heating. One of the most popular is adding a heating element to a ventilation system, which will only come into action when outside temperatures are almost at zero. For domestic hot water, a boiler is still recommended.
Double glazed windows are a must, but there can be difficulties with this when working on an old house. Luckily, The Heritage Window Company can install double glazed windows that will maintain the original look of your property. These will allow you to manage passive solar gain. That is, using the warmth from the sun as free heat.
While it can be argued that the lack of extreme weather in the UK does not warrant an investment in Passivhaus, there are savings to be made when the Passivhaus standard is tweaked. If you want to reduce the impact on the environment and your wallet, it’s well worth some consideration.