Wednesday, December 5, 2012

Heating cost comparisons

What is the cheapest way to heat your home?  I'll crunch the numbers for a house in Nova Scotia.

Electric baseboard heaters are cheap to install, but expensive to use.  The current cost of electricity in NS is 14.6c/kWh tax in.  With one kWh of electricity providing 3412 BTU of heat, electric heating costs 4.28c/kBTU.

If you use the time-of-day tariff,  off-peak electricity costs 8.15c/kWh tax in.  That reduces electric heating costs at night and weekends to 2.39c/kBTU.

Furnace oil is selling for $1/L, and provides ~36kBTU when burned.  With a 90% efficient condensing boiler, the cost is 3.09c/kBTU.

Discount propane sells for ~60c/L at Costco, and provides ~26kBTU when burned.  With a 90% efficient condensing boiler, the cost is 2.56c/kBTU.

Wood pellets provide ~8kBTU/lb, and sell for ~$5 for a 40lb bag.  At 90% efficiency, the cost of heat is 1.74c/kBTU.

Heating with wood pellets is pretty cheap, but still not the cheapest.  A geothermal heating system will have a COP of at least 3.0 (4.0 can be achieved with new high-efficiency heat pumps).  Take the 4.28c/kBTU cost of electricity and divide by the COP (3.0) to get a heating cost of only 1.43c/kBTU.  With a time-of-day tariff and off-peak use, the rate is just 0.8c/kBTU.


Don't forget the cheapest (free) source of heat - the sun.  So on those sunny winter days, open the curtains, raise the blinds, and let the sun shine in!