June 24th, 2019

The Real Cost of Heating

We are all familiar with the factors that go into the cost of heating a house: insulation values, window selection, infiltration levels, the absence or presence of convection, and the furnace and duct efficiency. However, one factor that can more than double a heating bill is the cost of one fuel over another. We would like to show you a comparison.

You can have a major impact on a heating bill by selecting the right fuel and by selecting the right furnace efficiency. With increasing fuel prices, it is no longer adequate to look at first cost only, that is, installing the least expensive system to keep the cost down. Rather, installing efficient equipment saves you money in operating costs and can cut down your total costs.

Furnace efficiencies are most readily comparable if they are expressed as an Annual Fuel Utilization Efficiency. This is the AFUE for gas, oil, and propane furnaces, as well as the HSPF for heat pumps. These numbers take into account temporary inefficiencies that occur during the start-up and shut-down of each heating cycle. This is not the efficiency that your technician will measure when he comes to tune up your heater. We have used these annual numbers in our comparison.

Prices for utility-delivered natural gas and electricity are regulated, and therefore change slowly and tend to ride over the short term ups and downs of the petroleum market. However, both heating oil and propane are made from oil, and their unregulated prices can change overnight with supply, weather, world political climate, and stock market changes.

Energy is measured by the BTU. Each BTU contains about the amount of energy that is given off by a wooden kitchen match burned end-to-end. Electricity is sold by the Kilowatt Hour with 3,413 BTU per kWh. Natural gas is sold by the hundred cubic feet with 102,000 BTU per ccf or by the therm with 100,000 BTU per therm. Oil is sold by the gallon with 138,500 BTU per gal. And propane is sold by the gallon with 91,500 BTU per gal.

Current electric charges in the area are about 15¢ per kWh, natural gas is about $1.40 a ccf, propane is about $3.00 a gallon, and oil is about $3.20 a gallon.

The annual cost to heat a 2200 square foot existing house of average energy consumption for different combinations of fuels and furnaces:

  • Natural Gas in an 80% furnace: $1215
  • Natural Gas in a 92% furnace: $1095
  • Oil in a 70% furnace: $2185
  • Oil in an 80% furnace: $2004
  • Propane in an 80% furnace: $3143
  • Propane in a 92% furnace: $2632
  • Electric Baseboard: $2485
  • Heat Pump with 6.65 HSPF: $1284 (includes electric backup)
  • Heat Pump with 7.5 HSPF: $1135 (includes electric backup)

So the moral of the story is “don’t heat with an electric baseboard” – and this includes small portable electric heaters. The list will help you decide if changing fuels is a good idea, or if increasing the efficiency of the heater you buy is a good idea. If you have natural gas (not propane), that is the way to go, but if not, consider a heat pump – the new, very efficient units can heat for 2/3 of more standard heat pumps shown on the list. And call us to make your house as comfortable as possible before you buy a heater – you may find you can buy a smaller one when we are finished.

These numbers are theoretical and are for comparison only. Studies have shown that heat bills can vary by a factor of 3 in the same house depending on the occupants.