Use this calculator to estimate how much you can save by switching from an oil boiler to a heat pump:
Important Note
This calculator assumes that you keep your home warm all day.
If you have a poorly insulated house and use a “blast of heat” each evening, then the comparison is not valid. Heat pumps do not work well under such conditions, and you must upgrade the home’s insulation before installing a heat pump.
Oil Boiler Efficiency
You can get the theoretical efficiency of an oil boiler from the datasheet. Typically, this will be around 65% for a non-condensing oil boiler, and around 87% for a condensing boiler.
However, for condensing boilers, the real-world efficiency is often much lower than what the datasheet says. Unless you’ve got weather compensation enabled, or have finely tuned the water flow temperature, it’s unlikely that your condensing boiler is operating anywhere near its theoretical efficiency.
Heat Pump Efficiency
Real-world heat pump efficiency varies massively. Some examples below:
| Efficiency (%) | SCOP Score | |
| Premium ground source heat pump, with underfloor heating and excellent design and installation | 600% | 6 |
| Good quality air-source heat pump, designed and fitted by a skilled installer [upper end] | 470% | 4.7 |
| Good quality air-source heat pump system, designed and fitted by a skilled installer [lower end] | 370% | 3.7 |
| *Mediocre design and installation | 300% | 3.0 |
| *Botch-job | 160% | 1.6 |
Other Heating Systems
Night storage heaters can be cost-effective, with running costs close to those of heat pumps
Gas boilers and coal stoves have about the same running cost as oil boilers (Heat pump vs gas boiler running cost calculator)
Overall Economics of Heat Pumps
With carbon tax ratcheting higher, heating oil prices look set to increase over the coming years. This favours heat pumps over oil.
But you also need to consider the higher installation cost of heat pumps. So for the full picture, use the heat pump payback period calculator (vs oil).
Also keep in mind that heat pumps have several non-economic advantages over oil:
- Garden space: No fuel tank needed
- Safety: Heat pumps emit no carbon monoxide
- Convenience: Heat pumps don’t require kerosene refills
