A couple years ago I did some calculations to compare heating costs in Nova Scotia. Since then energy costs have changed a bit, and I have more accurate information on the efficiency of oil boilers and pellet stoves. As well I intend to add natural gas to the comparisons.
Electric heating costs have not changed much, with the cost of electricity now 14.95c/kWh. This equates to a cost of 4.38c per thousand BTUs.
Furnace oil is now selling for 95c/L. In my previous calculations, I assumed a 90% efficient condensing boiler. These are uncommon in NS, so I'll use the 84% efficiency of an oil fired boiler with a tankless coil. This equates to a cost of 3.14c/kBTU. Pie anyone?
Instead of propane which is not commonly used for space heating in NS, I'll look at the cost of natural gas. The current price of natural gas is $20.69/GJ. When the $21.87 monthly charges is factored over my estimate of 42GJ/yr of gas consumption for a moderately energy-efficient residence, the total cost per GJ is $26.93/GJ. With one gigajoule equal to 948 kBTU, and an efficiency equivalent to an oil fired boiler, natural gas heat costs 3.38c/kBTU.
For wood pellets, prices have increased so that 40lb bags are selling for at least $5.50. I've also found out that wood pellet stove efficiency tops out at around 87%, and for typical units is closer to 75%. After updating my calculations based on the higher price and lower efficiency, wood pellet heat costs 2.29c/kBTU.
With the recent popularity of air-source heat pumps in Nova Scotia, it is prudent to compare their cost of heat to other sources. A high-efficiency unit with a COP of 2.4 will provide heat at a cost even lower than pellets - 1.83c/kBTU. A lower efficiency unit with a COP of 1.4 will provide heat for about the same cost as oil - 3.13c/kBTU.