With the Polar Vortex descending upon us this week, I thought I would go through a little calculation to see which option makes more sense (and costs less dollars).
How to compare Natural Gas to Electricity
To be able to properly compare natural gas to electricity, we need to figure out how to compare their cost. Each of the two energy sources are delivered and measured using different units. Natural gas delivered and billed in therms, electricity in kilowatt-hours (kWh). Luckily, someone has already gone to the trouble to calculate how many kWh are in a therm — 29.3072 (source: Wikipedia).
Using this conversion factor, we can compare the relative costs of the two energy sources:
| Energy source | unit cost (Dec-18) | cost per kWh | cost per therm |
| natural gas | $0.554/therm | $0.019/kWh | $0.554/therm |
| electricity | $0.121/kWh | $0.121/kWh | $3.543/therm |
For the purpose of turning energy sources into heat, it doesn’t take a rocket scientist to figure out that natural gas is a much cheaper form of energy than electricity. Natural gas is 6.4x cheaper than electricity.
What about furnace efficiency?
If your furnace uses plastic pipes, it’s a high efficiency furnace (>97%). If you have a standard efficiency furnace (mine is ~85%), some of your energy is lost up the chimney. So for my situation I’ll need to adjust for that by dividing my unit cost for natural gas by 0.85.
| Energy source | unit cost (Dec-18) adjusted | cost per kWh | cost per therm |
| natural gas | $0.652/therm | $0.022/kWh | $0.652/therm |
| electricity | $0.121/kWh | $0.121/kWh | $3.543/therm |
This changes the cost differential slightly, but natural gas is still 5.4x cheaper than electricity.
Turn up the thermostat!
Bottom line is that heating with gas is several times cheaper than heating with electricity. If you have the option of heating with natural gas or electricity, natural gas is the way to go!