8 Sustainable Homes Desain

The fundamental principle of sustainable home design is to work with nature rather

than against it. In particular, this means harnessing the sun’s energy to help heat the house in

the cooler months whilst also preventing it from overheating in the summer. This can be

achieved through the careful siting of the building, balancing passive solar gain from glazing,

screening to reduce overheating and to help even out the temperature across the day,

incorporating thermal mass in the building’s structure and high levels of insulation and

airtightness.

The characteristics of the plot and planning situation will play a big part in informing

the type of sustainable home design that is most appropriate. If it is possible to have the

majority of the glazing facing due south, then there is the potential to build a passive solar

house, which uses the sun’s energy to provide most of the space heating requirement. North-

facing elevations should include minimum glazing and maximum insulation. If the best views

are from a different direction, then a super-insulated airtight house might be a better

approach. If the site has a slope, the building could be sited so that the north side is partially

or fully built into the slope to protect it from the elements. The earth’s thermal mass and

constant temperature can balance out the house’s climate. The distinctive sloping, south-

facing glazed atriums of many passive solar houses arises because the angle of 45° is the

optimum for maximising solar gain across the year. But large areas of glazing can be

incorporated into homes of other styles — even a classical façade. With super-insulated

houses, the approach to orientation is different: the heat requirement may be so low that

cooling becomes more of an issue than heating, and so too much southfacing glass is avoided.

Overheating can be reduced by screening out light. The sun is at its highest in the south, so

for summer heat it’s straightforward to design a small roof overhang, or brisesoleil —

horizontal slats over the windows. Low, powerful light from the east or west can be harder to

screen out, so think about using planting, blinds or shutters.

Tocreateasustainablehousetakesappropriatematerialsbecause a truly sustainable home

does not look solely at energy and water conservation, but also takes into account the

environmental impact of the materials used in its construction. As a general rule, the less

energy used in the production and transport of products and materials the better. However,

energy consumption can be mitigated in products such as solar panels and other renewables,

and also where materials have a very long lifespan, and can be reused or recycled, such as

lead, copper and other metals, and even concrete and clay brick and roof tiles. Timber must

be sourced from managed forests and should be certified as such, and not be from endangered

species. With all materials, the less waste and pollution created in the manufacture the better.

The principles of sustainable construction are closely aligned with those of the healthy home,

whereby materials are free of harmful chemicals, such as volatile organic compounds

(VOCs).