Cost Analysis: Residential Heating
Intro
On the way home to Pittsburgh for winter break, I stopped by my girlfriend's house in NOVA for a couple days and noticed that they used electric space heaters for much of their heating needs. Initially, I thought this had to be less cost effective, but decided to do a cost analysis to investigate. Electricity, natural gas, heating oil, and propane were compared and I found that, in Pennsylvania, natural gas heating is most economical, as expected. The other forms of fuel weren't far behind but electric heating was around 84% more expensive per unit heat. I made an online calculator as well so that you can enter your own, local utility costs!
Assumptions:
- Electric heaters are around 100% efficient because any electrical losses are typically lost as heat, which isn't really a loss for a heater...
- Furnace efficiencies are taken from Wikipedia. Example: natural gas heating is on the order of 95% AFUE efficient for latest-technology homes. This is just a rough estimate and should be investigated further before taking this analysis too seriously.
- Lower Heating Value (LHV) is used in conjunction with the AFUE efficiency to determine input energy.
- Utility costs are based on PA averages.
Utility Costs
| Utility | Price | Source |
|---|---|---|
| Electricity | 14.69 ¢/kWh | eia.gov |
| Natural Gas | 17.52 $/(1000 ft3) | eia.gov |
| Heating Oil | 2.636 $/gal* | eia.gov |
| Propane | 3.167 $/gal* | eia.gov |
Calculations
Using WorlfamAlpha, the cost per BTU of heat could be computed for each utility type.
| Utility | Cost per (105BTU) |
|---|---|
| Electricity | $4.31 |
| Natural Gas | $2.22 |
| Heating Oil | $2.24 |
| Propane | $3.64 |
Calculator
| Utility | Price | Cost/(105BTU) |
|---|---|---|
| Electricity | ¢/kWh | $ |
| Natural Gas | $/MCF | $ |
| Heating Oil | $/gal* | $ |
| Propane | $/gal* | $ |
*US liquid gallon
Discussion
Although natural gas was the most economical, utility cost and furnace efficiency are both factors which affect which fuel is most economical.
In western PA, we have a lot of natural gas wells. In fact, I'd bet there are 2 or 3 within 1 mile of my suburban house, hence the low cost of natural gas. In other geographical locations, it is very likely that other fuel sources are cheaper or even that fuel is so expensive that it exceeds the cost for equivalent electricity. This is certainly relevant to take into account.
The values were all based on latest technology furnaces, but many older houses likely still use older, less efficient furnaces. efficiencies drop around 10% for "standard efficiency" natural gas and propane furnaces and possibly more for very old heating oil furnaces.
Conclusion
I found in a preliminary estimate that, for my area, natural gas is indeed the most economical choice for residential heating.