Have you considered fitting a heat pump at home? They're not cheap, but will save you money in the long run by using free, renewable energy.

Here are 5 things to think about before getting one:

1. Most people opt for either a ground or air source heat pump because water source heat pumps need a lake, river, stream or other body of water to work, and most of us don't have one of those in our garden. The Energy Saving Trust says that ground source heat pumps cost from around £13,000-£20,000, while air source heat pumps are less expensive, at around £7,000-£11,000.

2. Ground source heat pumps extract warmth from the earth and use it to heat your home and hot water. The (above-ground) pump is connected to a series of pipes (the ground loop) buried in the garden and can be used in all seasons, although you may need a back-up heating system in winter.

[Read more: Upgrade your boiler: 5 tips for a better heating system]

3. Air source heat pumps take heat from the air outside, increase its temperature and use it inside the home. There are two types - air-to-air pumps and air-to-water pumps. The former produce warm (and also cool) air and circulate it through fans. Air-to-water pumps supply your home's (wet) central heating system. Air source heat pumps can work at temperatures as low as -15 degrees C outside, but can be less effective when it's colder than -5 degrees C, so, again, another form of heating may be necessary in winter.

4. If your home's heated by radiators, they won't get as hot with a heat pump as they would with a boiler - you'll need to have them on for longer or replace them with more powerful ones. The perfect partner for a heat pump is wet underfloor heating because both work at lower temperatures. However, wet underfloor heating isn't particularly easy or cost-effective to retrofit - it's often better to install when building or renovating a property.

5. Heat pumps warm the air gently, so they're not ideal if your home heats up and cools down quickly. For this reason, they work most efficiently in homes with good insulation and draught proofing, which a lot of period properties lack. While you should cut your home's CO2 emissions by fitting a heat pump, how much will depend on the type of heating you're replacing.

Heat pumps need electricity to work, so the most environmentally-friendly option is to generate your own electricity using solar panels or a wind turbine, for example, but these are expensive to install.

Do you have a heat pump? Tell us your tips in the Comments box below.