How do GHPs Compare to Other Systems?
To compare heating systems (apples to apples) you need a common denominator. We have choosen to use "1 million BTUs" because many homes use between 45,000 - 85,000 BTUs per hour on a very cold winter day, which is just over a million BTUs per day (about 125,000,000 BTUs per year).
Because each system uses a different fuel type we need to know how many BTUs a unit of fuel contains (A). Then, using efficiency ratings of each system (B), you can calculate the number of units required to create 1 million BTUs (C), which is a used to compare costs (see calculator below).
A |
B |
C |
||
| Fuel Type | Fuel Unit |
BTU/Unit |
Heating System |
Units Required 1 million BTU |
#2 Fuel Oil |
Gallon |
138,000 |
65% 78% 84% 92% |
11.15 9.29 8.63 7.88 |
| Natural Gas | Therm |
100,000 |
65% 78% 84% 92% |
16.7 14.3 12.5 11.1 |
| Propane | Gallon |
90,000 |
65% 78% 84% 92% |
17.5 15.0 13.1 11.6 |
| Electric Baseboard |
kWh |
3,413 |
100% |
293 |
| Air Source Heat Pump |
kWh
|
3,413
|
293 / 2.5 COP
(Warm Climate) 293 / 1.8 COP (Cold Climate) |
117.20 |
| Geothermal Heat Pump | kWh
|
3,413
|
293 / 3.9 COP
(Warm Climate) 293 / 3.4 COP (Cold Climate) 293 / 4.2 COP (Hydronic) |
75.13 86.18 69.76 |
Heat Pump efficiency is measured as Coefficient of Performance (COP). For instance a baseboard electric heater has a COP of 1 (it is 100% efficient). Geothermal Heat Pumps in the Northeast have COPs of 3.4 or higher (depending on system design and performance).
Therefore to generate 1,000,000 BTUs simply enter the units required (Column C) and the cost per unit of fuel.
| Type of Fuel | Units Required
per M From Col C Above |
Price per Gallon
of Fuel or kWh |
Cost per Million BTUs ($) |