Greener homes

These pumps extract heat from the air outside and then increase its temperature, before using it to heat your home.

There are two types of pump - air to air and air to water. The former produce warm (and also cool) air and circulate it around your home through fans.

Air-to-water pumps supply your home’s (wet) central heating system. However, they don’t make the water as hot as a boiler does, so you may need to fit bigger radiators because the ones you have won’t give out as much heat, or install (wet) underfloor heating, where the water doesn’t need to be so hot.

Underfloor heating is a good option with a heat pump, but is often expensive and disruptive to retrofit - it’s ideal for renovations and houses being built.

According to the Energy Saving Trust, fitting an air source heat pump costs around £6,000 to £10,000. How quickly you’ll get that money back depends on a number of factors, but you’ll save most money if you’re replacing a coal-fired or electric heating system (if you have mains-gas central heating, an air source heat pump may not be for you).

The good news is that once the Renewable Heat Incentive (see www.which.co.uk) starts (probably next year), it should take less time to recoup your investment.

This Government scheme will pay people who heat their homes using renewable technologies, including air source heat pumps.

Even though the scheme isn’t up and running yet, you may be able to get a Renewable Heat Premium Payment (see www.energysavingtrust.org.uk) to help you with the cost of installing a heat pump.

As well as providing you with an income (assuming the Renewable Heat Incentive goes ahead), your pump should also cut your home’s CO2 emissions (depending on what sort of heating you’re replacing).

The problem, of course, is that although air is renewable, these pumps need electricity to work. The most eco solution is to generate your own electricity, using a wind turbine or solar panels, for example, which is another big investment.

Air source heat pumps rarely need much maintenance, but they may not work as well when it’s colder than -5C outside (although they can work at temperatures as low as -15C), so another form of heating may be necessary in winter.

It is, of course, vital that your home’s draught proofed and well insulated for the heating system to work efficiently.

Whether or not you need planning permission for an air source heat pump will depend on where you live in the country (and sometimes other factors), so check with your local planning department.

As always, if your home’s leasehold, you may need the permission of the freeholder to make an alteration such as fitting an air source heat pump.

And if it affects a wall or boundary you share with a neighbour, it may be necessary to draw up a party wall agreement with them.