The Dream of the Sustainable House

Wikipedia states that 40% of fossil fuel consumption in America and the European Union goes into heating/cooling and powering houses. This is the very opposite of sustainable. This reliance on using fossil fuel cannot be maintained because oil, coal and natural gas are limited resources. However, when we talk of sustainable design it is not just fossil fuels but all natural resources that have to be taken into account. A truly sustainable house produces a net loss to environmental assets of zero.

There are a number of ideas prevalent concerning sustainable housing. One of the most popular is the idea of the zero energy building (ZEB). This is defined as a building which can power itself from renewable energy sources such as solar energy or wind energy. No external source of electricity is used. Zero energy buildings make heavy use of photovoltaics and wind turbines. They also use passive solar heat gain and thermal mass to stabilize internal temperatures.

There have been lots of zero energy buildings constructed in Europe and North America. Much of the technology needed to make your house a zero energy residence can be bought off the shelf. If you are designing your own house then you can buy computer software that simulates changes in power consumption, solar heat gain etc. brought about by alignment of the house to the sun, seasonal changes etc.

Of course, people in the developing world who live in huts, tents, caves and corrugated iron sheds often dwell in zero energy buildings simply because they have no electricity.

Another successful architectural ethos that has been called ‘sustainable’ is the passive house. This is popular in Germany and Scandinavia. The passive house and the zero energy building share many goals – such as better insulation and energy efficiency, but the passive house seeks to use less power. This is achieved by superinsulation. Superinsulation involves making doors and windows air-tight, increasing wall gaps to put in more insulation and other techniques. A passive house aims to be like a sleeping bag trapping all the heat in a house so just the heat generated from electrical appliances and human beings is enough to heat the house. In mild weather, natural ventilation is used. In the winter, solar energy is used to drive a small heater and fan that circulates warm air in the home.

Several adoptions have to be made to make a passive house for hot and humid weather but it is possible.

Connected to the idea of sustainable design is green interior design. The goal of making the interior of a home energy efficient and healthy compliments the goal of making the architecture energy efficient.

Out of all these considerations of a sustainable house there are certain common threads:

1) A house must be as small as possible. Small is easier and more efficient to heat. A lot of architecture that is influenced by ‘green’ issues breaks this rule. The desire to make an effect using space is too much to withstand for famous architects.
2) Harmonize with the site. Try to fit into the local environment.
3) The use of natural heating and cooling plus solar energy.
4) Located near the place of work for the homeowner. Again this rule is often broken by the big money projects. Many ‘eco’ or sustainable houses are the toys of the rich and require a high carbon output to reach.
5) The preference to refurbish older buildings where possible. This conserves natural resources and is a good example of upcycling.

The problem that is common to a lot of thinking about sustainable housing is that too much is made of the carbon input and carbon cost of running a house. Yes it is vital for the goal of sustainability to cut the house off from the national grid and avoid carbon emissions from heating/cooling. But it is also vital to look at the other natural resources involved in the building project. Iron ore, minerals, wood, cement, electrical wiring, glass are all made from natural materials that are limited. Some involve the carbon intensive practice of mining. Then there is transportation of the materials and the processing and assembling. There is a water bill to consider. The more you look into what goes into a house to make it the more you realize that it is draining natural resources and cannot be considered sustainable in the widest sense of the world; especially if everyone got a ZEB or passive house.

This problem is recognized by those seeking to design ‘low tech houses’ that use local natural materials. They are not focused on aesthetics of big sheets of glass but just being as low tech and efficient as possible. It seems that the closer we get to those poor people who live in zero energy huts and sheds the more we are approaching sustainability. Of course over the next 50 years when the world population of homo sapiens (the irony) doubles, nothing that is done by humanity will be sustainable because we ourselves will have become an unsustainable burden on the planet.