Rinnai 323 Gas heater

My Rinnai

I saw frost for the first time in 2007 today. My wife has started to grumble about the cold. And the stores are full of heaters for sale, all of them claiming to be energy efficient. It’s time to review which heating options will warm your home without heating up the planet too much.

First, the worst: electric underfloor heating and open fireplaces. Talk to any underfloor heating salesperson, and they will tell you that underfloor heating is incredibly efficient. Talk to any homeowner who has had it installed, and they will tell you that their toes are very warm on the tiles (don’t these people own slippers?) and that their electricity bill shot up the day they turned on the underfloor heating.

The issue is not so much whether underfloor heating is efficient or not. It’s a form of central heating, and most South African suburban houses are not built for central heating. They have big, draughty, single-glazed windows, and uninsulated walls and ceilings. When I moved into my house, each room had a brick with big holes in it to let in outside air, for heaven’s sake. To centrally heat such a house with coal-derived electricity is an environmental abomination.

Open fireplaces have lots of charm, but two big drawbacks. The first is that most of their heat goes up the chimney, and in doing so, draws cold air into the house through any leaky door or window it can find. Nature abhors a vacuum. The second drawback is that, whether burning wood or coal, they emit lots of pollution up the chimney.

According to The Consumer’s Guide to Effective Environmental Choices, by Michael Brower and Warren Leon:

On a per-household basis, the most polluting option is wood heat. The main reason is the very high emissions of particulate matter from uncontrolled fireplaces and wood stoves. Particulates are given a heavy weight in our air pollution index because of strong evidence that they cause serious health problems.

I hate to diss wood heat, because it is carbon neutral, presuming that a new tree is growing in the place of the one you are burning. A good compromise is a modern, super-efficient wood stove, such as the ones sold by Franco-Belge or Morso. The best wood stoves produce one-twelfth the emissions of a typical fireplace.

Electric heat in all forms is relatively efficient, but that isn’t a great help because generating the electricity from coal is very inefficient, and releases far too much pollution and carbon dioxide. If you are heating a relatively small space for a couple of hours in the morning and few hours in the evening, however, it is an affordable, environmentally tolerable option.

Research at the University of Pretoria found that the quickest, most efficient electric heater for warming a space is a fan-assisted heater with a thermostat. Fin radiator heaters—often called oil heaters because of the liquid circulating inside them—and other heaters without fans are slower to heat a room and let much of that heat drift to the ceiling.

Radiant bar heaters, which glow red, do not heat a space, but can efficiently heat any person who stays close to them. If you are staying put, reading or working, they may be your best option, particularly if you buy one with a low wattage setting. (1000 W or less) Leaving one of these heaters on when no one is in the room, however, is a complete waste. An electric blanket is another good option for anyone who isn’t moving.

If you are lucky enough to live in a Johannesburg suburb with piped gas, this is an excellent option, particularly now that South Africa is importing natural gas from Mozambique. Gas is the cleanest-burning fossil fuel and releases the least carbon dioxide, too. Bottled propane gas also burns cleanly, but its global-warming credentials are tainted by the fact that in South Africa much of it is produced from coal. Gas is also more efficient than coal-derived electricity because the heat from burning the gas goes straight into your house, bypassing the inefficiencies of generating electricity.

Burning gas in an open fireplace takes us right back to where we started, however, with heat escaping out of the chimney. My favourite gas heaters are the pricey, but super efficient ones made by Rinnai. My Rinnai has given me three years of faultless service. I keep large, 48 kg bottles of LPG outside my house, piped to a wall outlet where I connect the Rinnai. It produces heat in seconds and uses very little gas. (To find a local dealer, phone the distributor Jay MacDonald and Sons, 021 696 7930.) The only problem is that my children fight over who gets to sit closest to it when they turn it on in the mornings.

I’ll take a risk and produce an unscientific ranking of heaters from best to worst:

1. Gas heater with piped natural gas
2. Gas heater with LPG
3. Modern, efficient stove burning wood
4. Modern, efficient stove burning anthracite
5. Electric bar heater for warming people who are staying in one place
6. Electric fan heater with thermostat
7. Other Electric heaters
8. Gas fireplace
9. Wood fireplace
10. Anthracite fireplace
11. Electric underfloor