We live in a world where there is an ever growing demand for energy to heat and cool buildings; power the manufacturing industries and keep our transport systems running. The building sector accounts for the majority of energy consumed in the World. Add to this the ever increasing population and the uncertainty of energy supplies and it is reasonable to assume that the cost of energy is likely to rise.


The building industry has a duty to minimise its energy use and to this end low energy buildings such as those designed under the Passivhaus principles are almost certainly to become more and more the norm.


The design and construction of a Passivhaus building is based on the following basic principles:





Money spent on extra insulation in the building is an investment with an ongoing, and to be presumed, increasing return as time goes on. The insulation layer to the building is higher than the level required by current building regulations and is much more carefully detailed to ensure complete “wrapping” of the building without gaps in the insulation layer which are common occurrences in normal building construction.





The solar gain through south facing glazing is an important factor in the warming of a building in the colder months. The minimising of overheating in the summer months by deeper eaves and shading devices ensures an equable temperature is maintained





An important aspect of the low energy home is the minimising of incidental draughts. The current Building Regulations stipulate that new buildings be sealed to a level of 10 air changes per hour (ach). The Passivhaus Standard is for 0.6 ach (nearly 17 times as airtight!) This has two profound effects; the reduction in heat loss through air leakage and and improved comfort level due to lack of draughts (wind chill)





As the Passivhaus experiences minimal accidental air infiltration it is essential for a managed ventilation system. The normal house provides ventilation generally by means of trickle vents fitted to doors and windows. This has two disadvantages in heat lost from the building and ventilation rates at the mercy of wind speeds resulting in draughts. The Passivhaus has a ventilation system that draws warm moist air from Bathroom, Kitchens and Utility Rooms extracts via a Mechanical Ventilation Heat Recovery unit (MVHR) reclaiming upto 95% of the outgoing heat to pre-heat the incoming fresh air.





The Passivhaus utilises high performance triple glazing and airtight sealed windows of a much higher insulation value than a normal modern building. Apart from the obvious advantage of reduced heat loss and draughts it leads to a much quieter house with the added advantage that unlike cold windows which are not comfortable to sit close to due to the cold air “waterfalling” off the cold glass. Every part of the internal space of a Passivhaus is of near equal comfort





In my previous, Victorian-built house, I had noticed that during the cold wet winter months the basement workshop, though un-heated, was always at a reasonable temperature due to the thick masonry walls and surrounding earth retaining the heat. I was further pleased to note that during the occasional heatwave the basement offered, for the same reason, a relief from the heat. In the design of a Passivhaus the inclusion of a masonry walls and stone floors greatly adds to maintaining an even temperature throughout the year





A Passivhaus has the following advantages:


• Lower energy bills


• No cost of installation of gas central heating system


• No unsightly radiators to clutter up the house making furniture arrangement easier


• No “problems with the boiler” and periodic plumbers servicing and repairs


• Much improved air quality


• Reduced problems with damp


• The house is quieter


• There are no draughts


• You will be less of a drain on the Earths resources



PGS Architects Limited. Cobbles, 28 Trelawney Lane, Peverell, Plymouth PL3 4FD


Telephone: 01752 225 645


Mobile: 0791 9150 800


Email: peter@pgs-architects.com