Climate-wise House Design: Energy-efficiency
Dr Bob Rich

General considerations
Polar climates
Temperate and cool temperate climates
Humid tropical climates
Desert climates

   I wrote this essay 20 years ago, and updated it in 2010. It is still accurate, and more relevant than ever.

General Considerations

   How much was stolen from your children's future when your house was built?
    Everything has a cost, and this is not only in money. Some of the resources used are irreplaceable: mineral ores, old growth forests, topsoil, fresh water, clean air. Even though some of these are replenished by nature, we currently use them up far faster than the natural repair rate.
    Also, everything has to be processed and transported, and all this uses more resources, eats up more energy.
    I will never see a tiger or an orang-utan, except perhaps in a zoo. Just the same, I will be impoverished by their passing. This will happen through habitat destruction, an inevitable consequence of the hunger for raw materials in wealthy countries.

   When something is used up, eventually it is turned into something else. Energy use generates

   Almost everything industry does leads to chemicals in the air and water. Is it an accident that in 2013, about 124,900 Australians were diagnosed with cancer? An estimated 149,990 are expected to be diagnosed in 2020. In 2009, the risk of developing cancer before the age of 85 years was 1 in 2 in men and 1 in 3 in women. [Source]
    When I first got interested in building, there was a vigorous demolition industry, supplying second-hand building components. It has all but disappeared. Most demolitions and alterations yield only solid waste, taken to over-full garbage tips.

   We should build as if the future mattered. Here are a few suggestions on how to achieve this.

Large is Lousy (the opposite of Dr Schumacher's 'Small is Beautiful'). The first house my wife and I bought in about 1970 was 12 squares, an average size then. When we built a 15-square house in 1980, it was considered a little small. New houses now are typically 24 squares and up. And in the meantime, average family sizes have dropped. So, fewer people occupy more space.
    The amount of space you 'need' is a matter of habit. You can get used to anything. So why should we allow the media and industry to con us into an upwardly mobile set of 'needs'?
    All sorts of costs go up in proportion to size:

   We could not afford the extra space if we had to pay the true value. We can -- because much of it is stolen from the future, and from people now living desperate lives in poor countries.

Recycle My house cost me $10,000 in materials. Much of it was free, the throwouts of others, or second hand. Of course, there is a cost in time. Seeking, collecting and processing recycled material is time consuming. For example, I'd like a cent for every rusty nail I've pulled out of old timber. But the result is an environmentally cheap house that is actually stronger and more durable.
    Why? Because in past years, raw materials were of a higher grade. Timber was from older, slower-grown trees. Such resources have been mined out, so new stuff is what used to be considered rubbish.

Choose materials with care My pet hate is fired bricks and roof tiles. As a first approximation, the manufacture of one brick generates 1 Kg (over two pounds) of CO2.
    How many bricks are there in your house? In your country? In the world? How much better off would we be if all of them were replaced by something less energy-hungry?
    A brick is not even a good building material. Moisture penetrates it. Being a good transmitter of heat as well as having a high density, it AMPLIFIES the outside temperature. On a hot summer's day, it is hotter inside an uninsulated brick house than outside. The converse is true in winter: the bricks cool the house.
    A fibro-cement or weatherboard (clapboard) house is cheaper, faster to build, is no more endangered in a bushfire (as long as the outside is painted white), gives you a better internal climate, and is far less damaging to the environment. It does need more maintenance, but you might use fibro-cement weatherboards.
    Aluminium is another energy-hungry material. If electricity was properly priced, aluminium would be dearer than gold. Aluminium door and window frames are only warranted where a flood can be expected. But the best thing is not to build on flood-prone land.

Timber Where possible, use recycled timber. The next best thing is plantation-grown, though it would be good if less chemicals were used in timber plantations. Also, we should discourage the practice of clear-felling forests and replacing them with plantations. Trees for timber should be planted:

    Try to avoid timber from old growth forests, particularly tropical rainforests. Even selective extraction is bad, because it transforms the ecosystem. In Europe, where this has gone on for over 1000 years, nature has adapted to man. That is, all the damage was done a long time ago. But in Australia, in the tropics, even in America, the complexity of the forest is decreasing, and this endangers the existence of many species. Try not to add to this.

Repair instead of replace This used to be the rule, and must be again if we are to survive as a species. The throwaway razor is the symbol of our society. It's far better to have a tool you use many times, sharpening and maintaining it. Actually, there is an even better option: resist. You can do without all that consumer junk, and believe it or not, live a happier life for its absence.
    I don't need a razor at all. You see, that's why I wear a beard.

Build for your climate 99% of houses currently being built are obsolete, because they ignore climatic requirements. We have passed through the period of cheap energy. Fifty short years ago, fossil fuels were thought to be unlimited, and 'pollution' hadn't entered people's language. Now we know better. The polar ice caps are melting! This is scientifically proven, and could endanger the livesof milions of people including you! Any house built without energy-saving in mind is obsolete.
   It is possible to build a house that takes minimal amounts of energy to heat and cool, maximises the use of daylight instead of artificial light, and minimises the energy costs of manufacture of its components. This is not a matter of expensive gimmicry, but of a little research, and paying attention to energy considerations. As a general rule, copy the traditional architechture of pre-technological people who have successfully lived in that kind of climate for a long time. For example, in the desert we should copy the earth-walled forts of the Middle East or the cave dwellings of the Pueblo Indians of New Mexico.

Polar Climates

   The first consideration when living in any extreme climate is to become adapted to it. This is achieved by doing regular vigorous physical exercise out in the open, a minimum of 20 minutes per session, 3 sessions a week. You then build up from this. After a month on the ice, Antractic explorers consider the freezing point to be a 'heatwave'.
    The Inuit and other Arctic peoples built igloos: small, heavily insulated domes. They could be heated with a remarkably small amount of fuel, such as a fat-burning lantern. They were equipped with an air-lock: a small compartment with two doors, one to the outside, the other into the living space.
    The same concepts can be incorporated into houses that use modern building materials and technology.

Temperate and cool temperate climates

   The first basic concept is the energy-efficient house. It works like a thermos: you minimise energy transfer between inside and outside. The shape minimises the ratio of external wall to volume of air inside. A two-storey cube is the extreme, but an approximation is sufficient. The raised timber floor is insulated underneath, the cavity walls are insulated, and there is as much insulation under the roof as possible. Window area is the minimum permitted by regulations, and windows and doors are efficiently weather-sealed. Ceilings are low, and painted white. Walls are also painted white, both inside and out. This reflects radiation, minimising heat transfer. The house is as small as possible. Heavy drapes can curtain off the windows. They have box pelmets over them to minimise the circulation of air caused by cooling through the window.

   Such a house will stay remarkably cool in hot weather, and will take a very small amount of energy to warm even in the coldest winter.

   The solar-efficient house is an improvement even on this. Shape is changed to a rectangle with the long side 1.5 times the length of the short one, and facing towards the sun. The wall facing the winter sun (south in the northern hemisphere, north in the southern) is mostly window. This allows winter solar gain: light energy entering through the windows is absorbed by inside materials, and re-radiated as heat. This is trapped by being reflected off the glass. A device is needed to keep out the entry of direct sunlight in the summer. Usually, this is a suitably sized roof overhang, capitalising on the fact that the summer sun is higher in the sky.

   The second change is the addition of thermal mass: heavy-weight materials to absorb daytime energy, to slowly re-radiate it when the air starts to cool down. Usually, this is a floor in contact with the ground: concrete slab, stabilised earth floor or the like.

   There are working examples of solar-efficient houses in Britain, and even as far north as Denmark. In Melbourne's climate, it is possible to build a house that needs no installed heating at all. An example is described in my Earth Garden Building Book.

Humid tropical climates

   I must emphasise, the first line of 'defence' is to adapt to the climate. What is killing heat will become comfortable, or at least bearable after some weeks, as long as you force yourself to do some regular aerobic exercise.

   The best example of appropriate building design for the humid tropics is the Dayak longhouse from Borneo. Heavy stumps are driven into a river bed, and a timber platform is constructed over them. A light frame holds up walls woven from palm fronds. The roof is a very thick layer of thatch. The overarching jungle provides shade.

   This structure is perfect for human needs in the tropics. The platform is above the level of the highest floods known. Even the heaviest hurricane will leave it there, at the worst destroying the lightweight construction above it, which can be rebuilt in a day. And because this structure is flexible, it is likely to survive strong winds.

   Being in flowing water, the house is free from mosquitoes, which breed in still water. It has the blessing of evaporative cooling. The lightweight walls allow the breeze to filter through.

   Exactly the same principles can be applied using modern materials, techniques and privacy requirements.

Desert climates

   A desert is a very hot place in the daytime, and freezing cold at night. Indigenous architecture uses this fact. Every surface is painted a blinding white. Structures are extremely massive, so that daytime heat soaks into the walls, keeping the inside considerably cooler; then this heat is gradually released during the night. Windows are kept as small as possible to minimse heat transfer between outside and inside. Flat roofs also tend to reflect heat, and are pleasant living space in morning and evening.


To index page