running costs for heating the house

Running cost of a heat pump


A heat pump is a device that can economize your running costs for heating the house. The overall scheme of how can you do that is the following:


  • you install a ground, air or water pump on your house
  • you receive the heating with a coefficient of efficacy (CE) between 3 and 4.3 compared to your current heating device that is based on fossil fuel, pellets, oil or wood and having CE around 0.7-0.95 as max
  • if you install the device that is allowed according to RHI scheme, you also receive a compensation for being an eco-friendly guy.


There are different types of heat pumps that impact the running costs


The types are ground, air, and water pump. They all have approximately the same physics of work but differ in installation and running costs, the same as the level of compensation by RHI. For instance, the air source heat pump cost is the lowest (around £4.000 for installation), the same as its efficacy: its CE is around 2.2-2.8. The ground pump is the most efficient (about CE 4.0) and expensive (around £13.000-£21.000), but it also gives you the biggest RHI profit (£3.535 yearly compared to £1.373 for an air pump for a 3-bed detached house). It means that only thanks to RHI, you will completely refund your initial installation payment and will earn profit – even not counting the economy on bills themselves.


Annual bills.

Your annual bill will depend on these factors (this is true for any type of heating system, not only for pumps):

  • how big your house is
  • what temperature do you find comfortable for you
  • how well is your house insulated from all sides
  • what is the average outdoor temperature
  • do you need a heating system for air inside the premises only or do you use it also to heat water


With all the same parameters, if to compare the pump and your current heating system, running cost of air to water heat will be as follows (considering 3-bed detached house):

Your annual demand in kWh will be around 18.000. Using various systems to reach this amount of heat, you will pay:

  • £1.644 with gas
  • £2.954 with electricity
  • £2.642 with oil
  • £1.245 with LPG.


The following amounts are applied when you use the heat pump:

  • £571 for heating premises
  • £646 for heating water for domestic needs.


Altogether, it makes £1.217. Now, we see that the effectiveness is better than of any other heating system.


RHI compensation

Do not forget about compensation. If you are a private house owner, you can count on 7-years payment RHI program. In case you have an air-source heat pump, you will get £1.373 per year (£9.611 per 7 years). The same for ground-source heat pump will be £3.535 and £24.745. It means you completely win back the installation costs and eventually receive environmentally-friendly heating with the lowest running costs of air source heat pump or a ground-source heat pump.


Some tricky points of heat pumps


However, despite the air to water heat pump cost is low, you have to select the heat pump very carefully as a number of parameters influence the output you will have (not all of them are indicated below):

  • the medieval temperature in the UK through November to March is under the lowest optimal working temperature for a heat pipe (+7 °C) and ranges between 4.2 to 6.9 °C. It means that the calculated efficacy will lower from 3…4.3 to roughly 2.5…3.5. However, with April to October temperatures, you will have greater efficacy and it will improve CE to roughly 3.5…4.5. So, if to consider the annual temperature, we can roughly take a factory-given efficacy when calculating your savings
  • the installation must be done right. If there will be any slips, the efficacy will also tend to lower. For instance, in the case with ground heat pipe, it may have too condensed pipes looping that prevent sucking of all temperature out of the soil, or ground heat may be too low compared to the location of the loops or the calculations may be done wrong and the average temperature will not be that high as expected. In the case with air heat pump, a fan may not have enough air circulating around it or the repeated air entry into the fan is not eliminated. That is why you have to choose professionals to install your device to reach the given efficacy.


All figures and numbers are approximate and stated for information only. Figures for your property may vary. Subject to survey.

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