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Introducing The Passive House

Here's the most interesting concept you're likely to have heard of in a while, if you're not familiar with it already, Passiv Haus. This is a house that does not need to be heated in winter, all it needs is the sun to shine on it, like any other house in the world and some warm bodies inside.

Ok, you say, what then? Well, how about an average temperature of 21 ºC inside, with average temperatures of freezing point or below outside! Think it's impossible, what if I said the concept was first put to the test 17 years ago when the first Passive Haus was built, and that there are thousands of homes in Europe which qualify for Passiv Haus status today?

The design and construction of a Passiv Haus takes many different factors into consideration, like efficient ventilation, excellent thermal insulation, sun angles and energy efficient appliances. In contrast typical South African homes are built with no insulation, then retrofitted with piping and cabling and appliances are usually selected only when occupying and furnishing the house, and currently it would be safe to say that aesthetics and cost are probably the determining factor when choosing residential appliances.

When comparing a Passive Haus to other efficient design homes, some interesting figures come to light. In 1980, 28 years ago, the Swedish Construction Standard for a home was to use approx. 160 kWh/(m²a) or kiloWatt hours per square metre per annum. A house may be deemed Low Energy when it consumes 30 kWh/(m²a), in contrast a Passiv Haus needs to consume less than half that figure at 15 kWh/(m²a)!

I do realise of course that the above figures may be completely meaningless to you, so let me put them into perspective. A standard size geyser (hot water heater, for our overseas friends ;->) of 200 litres, as fitted to many homes in our country, has an energy consumption of approx 4500 kWh per annum, in a household of 4 people. So to get our comparison right we have to take into account the probable size of a Passiv Haus if it were built in South Africa, we'll use a size of 250 m² (a 3 – bedroomed house). A Passiv Haus of that size would need to use less than 3750 kWh per annum to qualify as one.

Thus one normal South African geyser uses more energy (kWh) in one year to produce hot water than a Passiv Haus of 250 m² uses in the same year to keep its occupants at a comfortable temperature (winter and summer) and provide hot water and provide household electricity for the needs of the occupants.

Have I made my point? Isn't this something absolutely worthwhile considering if you are contemplating the construction of a new dwelling?