Air source heat pumps – energy efficient heating?

air-source-heat-pumpRecently I’ve been thinking about all the renewable energy options available to homeowners.

I’ve covered wind turbines, solar panels, geothermal and biomass in previous posts but there are many other options available.

There are water source heat pumps, heat recovery ventilation and wood gasification boilers for me to learn about.

Something we have been considering for a couple of years now, is an air source heat pump. One of our neighbours has one and is delighted with it. Yes, you still need electricity to run them but it’s far less than running electric-based heating in your home. They work a bit like a refrigerator in reverse – by extracting heat from the outside environment and transferring it, via a heat pump, to your home.


The advantages to these systems are simple installation, reasonable payback time and good conversion of energy – one kWh of electricity used by the air source heat pump will generate 3-4 kWh of heat to your home making it efficient to run.

Product finder

I’ve been playing around with a brilliant product pricing and discounts finder over on Enerfina. You simply choose the types of product you are interested in, punch in the square feet of your home (ours is around 1200), the age of your property (ours is 75 years old) then you’ll be asked some additional questions to help find the best products for you.


I was given a choice of four air source heat pumps, ranging from £3123 for the Mitsubishi Ecodan 5 kW (which is the one we were considering getting), up to £9421 for the Vitocal 8.6 kW indoor heat pump.

The price for the Ecodan is around £1500 less than I’ve seen it elsewhere. What’s more, air source heat pumps are eligible for the Renewable Heat Incentive where you should be able to claim back around 7.5p per kWh.

Renewable Heat Incentive

The goal of the Government, with their Renewable Heat Incentive Scheme, is to have 15% of the UK’s energy consumption generated from renewable sources by 2020.

It’s not just air source heat pumps that qualify. The following renewable technologies are eligible for the Renewable Heat Incentive:

  • Ground and water source heat pumps
  • Solar Thermal Panels
  • Biomass Boilers

Each technology has a different tariff for the householder to benefit from, ranging from 7p per kWh for ground source heat pumps to 18p per kWh for solar thermal.

What about you – do you have any renewable technologies installed in your home? If not, what stops you?


  1. chris levey on April 3, 2012 at 3:51 pm

    I hate to be a kill joy but I think you should read this before doing anything .As the link says the renewable-heat-incentive-scheme is being delayed and watered down.

  2. Mrs Green on April 11, 2012 at 10:47 am

    @chris levey: Not a killjoy Chris, I appreciate you sharing information – it’s good to be empowered…

  3. Mr Taylor on March 5, 2013 at 5:44 pm

    With a decent 5 head system costing over £12000 with installation, and offering approx 80% savings on your energy bill (£640pa on a typical £800pa gas bill, less £300pa in additional electricity bills to power the pump), that represents a net saving of £500 a year. So, 24 years before you start to see a return on your investment, by which time the pump will be knackered and need replacing. Unless the Government offer a decent RHI, no mateer how good these pumps are, they represent a very poor investment indeed.

  4. Mr Taylor on March 5, 2013 at 6:41 pm

    Sorry, that should have read a net saving of £340pa after typical pump running costs. So, nearly 36 years to see any return on initial outlay. Factor in the cost of one or perhaps even two replacement pumps in that time and you will probably be long gone before making a penny back. A decent RHI might redress the balance a little, but I doubt this could ever be as good an investment as solar PV.