Home Ownership Before you begin to adapt, convert or supplement your present heating system, determine its performance. Calculating furnace efficiency will help.

Remember that insulation plays a big part in energy conservation.

You'll be defeating the purpose if you install an energy-efficient system without having adequate insulation. You'll end up with a system that's far more powerful than you need, only to heat the great outdoors. Even the most efficient system can't perform up to expectations if it's installed in a leaky house.

Recommended insulation values are: RSI 5-9 (R 24-50) for walls; RSI 9-14 (R 50-80) for ceilings; and RSI 3.5-5 (R 20-30) for walls below grade. Different brands and types come with different RSI-values. Depending on your region, you may need more or less insulation.

Calculating oil/gas furnace efficiency can be done at home without expert assistance. Energy, Mines and Resources Canada will send you a simple cardboard slide rule to match the furnace's flue gas temperature with the percentages for efficiency (a local utility or service company will have them too). The rules measure "steady-state" efficiency, as opposed to "seasonal" or "transient" efficiency. The steady-state efficiency doesn't account for heat lost during down times — the energy used to bring air temperatures back up after the furnace has been off. The average seasonal efficiency of most conventional oil/gas furnaces can be 15 percentage points below the steady- state efficiency.




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Home > Home Ownership > Energy Economics > What Are You Living With Now?

December 4, 2008