The basics in the calculations are fairly simple, and the questions regarding them are common. Thus, I created this simple form to fill in some data. It delivers cost saving calculation times utilising comparisons between the alternatives. The shown alternatives are
- Using an eletric heater only
- Using an air/water heat pump
- Using a geothermal heat pump
The assumption for the calculations are that the different heat pumps are enough for heating the house without addtional electric heater, or that the differences in cost from needing such additions are small enough to be neglected.
The below input data are to make a rough comparison. The average heat consumption is assumed to be the heat consumption needed for the heating, and assumed to be fully replaced with the alternative heat pumps. It is important to think of it not as the electricity consumption, but the needed consumption for the heating. Thus, hot water is assumed not to be included, neither household electricity.
Also, if the heating today is fully or partly produced by a heat pump or non electrical furnace, their production, if they are to be replaced, has to be translated to corresponding needed heating kwh without them before entering the kwh need.
Below is calculated the needed times to get back the investment for the alternatives, assuming that the cost per kwh is 1 SEK.
- The electric heater is included as worst case reference, and is thus calculated without an investment in a new electric heater.
- The columns "Air/water Saving" and "Geothermal saving" shows the time it takes to get back the investment for respective of the alternatives, compared to keeping an electric heater. Observe that the less energy is needed fo rheating, the longer time it takes to get back profit after an investment
- The column "Geothermal saving above Air/Water looks at the pay back time for the decision to buy a geothermal pump, compared to buying an Air/Water pump. It is thus comparing the time it takes to get back the additional investment for the geothermal pump (the difference in investment) by the improved COP produced by that pump. A more thorough explanation for the reason for doing this kind of comparison is given.