Passivhaus Store

General information

A Passivhaus is designed for ultra-low energy consumption combined with consistently good internal air quality.

A Passivhaus is not about lots of advanced technology; rather, it is about changing the way we build. This means integrating design for low energy into the plans from day one, designing with an awareness of the impact of form factor, eliminating thermal bridges and radically reducing air leakage compared with standard builds, incorporating additional insulation and making use of solar gain.

From early in the design process, special energy modelling software – the Passivhaus Planning Package – is used to calculate how the proposed design will perform and a proven track record stretching back over two decades shows that the predicted performance is achieved in real life. This is something non-Passivhaus low energy builds often fail to achieve.

A Passivhaus uses around 90% less energy for heating than a typical building and 75% less than typical new builds. The air leakage rate (expressed in air-changes per hour @ 50Pa -ach@50Pa) is 0.6 or less. In a typical UK building it is over 10 ach@50 Pa.

Fresh air is introduced via a heat recovery ventilation system (MVHR) which removes the heat from the stale outgoing air which would normally be lost in a leaky conventional build. MVHR systems typically save upto 16.5kWh of heat for every 1 kWh of electricity used to run the system.

Triple glazed timber windows which are Passivhaus suitable and continue to perform well into the future ensure that there is no cold radiant close to the glass. This means there are no drafts coming off the windows and allows the full extent of the floor space to be utilised even when the temperature outside is -10°C.

You can read more about the Passivhaus standard and how to achieve it in The Passivhaus Handbook