Design
The Passive House Insitute in Darmstadt Germany has given a set of criteria which will be helpful in designing a Passiv Haus, (www.passiv.de) which are shown below. As well as this they have designed a set of spread sheets which can be used to verify that the design will achieve the standard. These are called the Passive House Planning Package and can be obtained from the Passive House UK for 120 pounds. The German Passive House Institute website also has a wealth of useful information, part of which is in English. Much of the work centres on keeping insulation levels high and maximizing solar gain.
The following values will help to achieve this:
Airtightness ≤ 0.6 h-1 @ n50
U-values for walls, roofs and floors ≤ 0.15 W/m²K
U-values for windows and doors ≤ 0.8 W/m²K
Thermal Bridges Ψ ≤ 0.01 W/mK
Efficiency of Mechanical Ventilation η ≤ 75%With Heat Recovery (Counter Flow Type)Hot water pipes insulated
Ventilation rate min 0.4 ach -1 or 30 m3/pers/h
Window glazing solar energy Transmittance g ≥ 50%
(Technical Specification from the Passive House Institute)
The drawings for the house in Cardiff can be accessed by clicking on the links below:
Cross section North to South (AA)
Below are some more pictures of the actual building as it takes shape.
August 2007