South African homes are built with virtually no regard to thermal efficiency at all. We are spoiled by our marvelous climate and thus don’t give much thought to the issue of building insulation when building or purchasing a home. However some parts of the country do experience short periods of quite intense cold during the winter. Consequently many of us simply freeze in winter whilst consuming huge amounts of energy trying to heat homes that were never designed to be thermally efficient. The same applies to cooling homes in areas which are subject to very high temperatures or humidity in summer.
We don’t tend to run our heaters constantly during winter because our poorly insulated homes would waste too much energy and the cost would be exorbitant for most. We tend to switch heaters on when we get home from work for example. Heaters which rely on radiation, such as the ubiquitous gas heater, are thus often a practical choice for our life styles because they can deliver heat to a room very quickly after being switched on.
Energy Saving Tips
There are no short cuts to using less energy to heat or cool your home, the only real answer is to improve the insulation. The best starting point is installing under roof and ceiling insulation (hot air rises, so a large amount of heat is lost through the ceiling).
From an architectural point of view, large expanses of glass, and double volumes dramatically increase the amount of energy required to heat a home. A single sheet of glass is a very poor form of insulation, whilst double volumes require a lot of energy to heat because all the hot air rises up to the distant ceiling. Unfortunately these are architectural features which many of us find appealing. Perhaps the answer is not to try and heat those parts of the home in winter and rather contain the heating to smaller rooms that have smaller windows. Alternatively investigate double glazing or adding thermal films to those huge windows, or simply heavy duty curtains!
If you are lucky enough to be designing your home from scratch, consider incorporating passive solar design. This idea entails using the sun to heat rooms in winter, while keeping sun out of the rooms in summer to keep them cooler. It requires that rooms face north (in the southern hemisphere), and that the eves and window sizes be appropriately proportioned to let the sun shine into the room in winter but not in summer.
Another option is a slow combustion wood or coal burning stove. They produce a lot of heat. Their design allows you to limit the amount of oxygen available for combustion so that they burn fuel very slowly, so the wood or coal lasts longer, which increases their cost effectiveness. This also enables more complete combustion so there is less ash afterwards. If you use wood for fuel please ensure you only use sustainably harvested wood (not slow growing hard woods that cannot be replaced).
In colder regions of the world, such as the USA and Europe, the modern heating trend is towards under-floor radiant heating in which the entire floor (not just the area above an electrical heat pad embedded under the tiles or carpet) is heated, usually via circulating hot water, which makes the floor a source of constant gentle radiant heat. This relies on the floor slab being designed or modified specifically for this purpose and being heated to a relatively constant temperature for a longish period of time (e.g. most of winter). Under-floor radiant heating is considered to be one of the most efficient methods of heating a home. However, this option is only really practical if installed during the construction of the home, and the installation is relatively expensive.
Alternative Fuel Prices
Surviving a Power Failure
Electrical heaters are clearly no use during a power failure. Supplying alternative electrical power to electric heaters is quite a daunting exercise because of the large amounts of power required. A powerful generator is normally the only practical option.
But given current fuel prices, combined with the 30-40% efficiency of an internal combustion engine, this is a VERY expensive way to heat a home.
Gas is another option, which is quite effective for heating, but its also a relatively expensive fuel.
Another answer is switch to other cheaper fuels such as coal or even wood if the local by-laws permit.