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Heating and hot water

Saving money on heating

In a typical UK household, more than half the money spent on fuel bills goes towards providing heating and hot water. And as fuel costs rise, having an efficient and cost effective heating system is vital. It’s one of the main steps you can take to reduce your carbon dioxide emissions.

Understanding your system

The first step to saving energy from heating is to understand your current system. Nearly all homes in the UK have either a central heating system – a boiler and radiators - or they use electric storage heaters.

Central heating: boiler and radiators 

This is the most common form of heating in the UK. A single boiler heats up water that is pumped through pipes to radiators throughout the house as well as providing hot water to the kitchen and bathroom taps.

Most boilers run on mains gas, but in areas where mains gas is not available, the boiler can run on oil, LPG (tank gas), coal or wood. Mains gas is usually the cheapest of these fuels, and it also has the lowest carbon dioxide emissions apart from wood. Some boilers also have an electric immersion heater as a back-up.

Gas, oil and LPG boilers may be combination (combi) boilers, in which case they heat the hot water as it is needed and don’t need to store it. Otherwise, the boiler heats up water and it is stored in a hot water cylinder that then feeds the taps.

If you have a system like this, you have plenty of options for energy-saving improvements:

  • Replace your boiler with a newer, more efficient model.
  • Fit better controls for your space and water heating - and use them to make sure your boiler only provides heat where and when you want it.
  • Switch to a cheaper or lower carbon fuel or technology. Find out about renewable technologies for generating electricity and heat.
  • Make any insulation and draught-proofing improvements that you can. 
  • Use chemical inhibitors to help maintain central heating system efficiency.

Chemical inhibitors

Using chemical inhibitors in central heating systems can maintain their efficiency – helping to save money on heating bills and reduce your energy consumption.

Corrosion deposits in an older central heating system can cause a substantial reduction in the effectiveness of the radiators, and the system as a whole – up to a 15 per cent reduction. The build-up of scale in heating circuits and on boiler components can cause a reduction in efficiency too. Using an effective chemical inhibitor can decrease the corrosion rate and prevent the build-up of sludge and scale – preventing system deterioration and helping to maintain efficiency. Typically, it can increase boiler efficiency by approximately 3 per cent.

Do you have a condensing boiler?

Since 2005 virtually all gas boilers that have been fitted in the UK are more efficient, condensing boilers. Condensing boilers have bigger heat exchangers that recover more heat from the burning gas, making them more efficient. You can tell if your boiler is a condensing boiler with a few simple checks:

  • If the flue is made of plastic, you have a condensing boiler. If it is made of metal you probably haven’t.
  • If your boiler has a plastic pipe coming out of the bottom of the boiler, through the wall and into a drain, then it is a condensing boiler.
  • If you have a gas boiler and it was installed after 2005, then it is almost certainly a condensing boiler.
  • If you have an oil boiler and it was installed after 2007, then it is almost certainly a condensing boiler.

If you don't already have an efficient condensing boiler, consider replacing your boiler with a newer, more efficient model.

Combi or regular?

Central heating boilers can be combination or regular. They heat the radiators in exactly the same way, but provide hot water for the taps in different ways:

  • a combi (or combination) boiler provides hot water directly, whenever it is required, and does not need a hot water cylinder
  • a regular boiler provides hot water when the programmer tells it to, and then stores it in a hot water cylinder until it is needed.

So if you do not have a hot water cylinder, you have a combi boiler.

A regular boiler is actually more efficient than a combi at producing hot water in the first place, but some heat is inevitably lost from the hot water cylinder, so a combi may be more efficient overall.

Electric storage heaters

Most UK homes that don’t have a boiler and radiators have electric storage heaters. These heat up overnight using cheaper off-peak electricity, and then give out the heat during the day. Electric storage heating is more common in flats, in rented property, and in homes with no mains gas connection.

Electric storage heating is one of the most expensive heating options in the UK, and it also emits more carbon dioxide than most. It is also harder to control electric storage heaters than radiators, especially with older systems.

If you have storage heaters, you will probably have a hot water cylinder heated by one or two immersion heaters.

If you have a system like this, you have several options for improvements:

  • Install new, more controllable storage heaters.
  • Fit thermostats and controls to make your existing system more efficient.
  • Consider making insulation and draught-proofing improvements.
  • Replace your system with an efficient boiler system.

Non-standard heating systems

Radiators or storage heaters provide the main heating in the vast majority of houses in the UK. However, a number of different technologies can be used instead, or in addition to, including underfloor heating, solid fuel stoves, range cookers, open fires, electric fires and gas fires.