Heating and hot water

new boiler

Understanding your system

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

It’s important to understand your current heating system. Nearly all homes in the UK have either a central heating system – a boiler and radiators - or they use electric storage heaters.

What is central heating?

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, and it has the lowest carbon dioxide emissions, apart from wood. Some boilers also have an electric immersion heater as a back-up.

If you have a central heating system, you may consider these energy-saving improvements:

  • Replace your boiler with a newer, more efficient model.
  • Fit better controls 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.

What type of boiler do I have?

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. Your boiler will be a condensing boiler if the following points are true:

  • The flue is made of plastic. If it is made of metal it’s unlikely to be a condensing boiler.
  • The boiler has a plastic pipe coming out of the bottom, through the wall and into a drain.
  • It was installed after 2005 (if it’s a gas boiler).
  • It was installed after 2007 (if it’s an oil boiler).

Combi or regular boiler?

Combi boilers

A combi (or combination) boiler provides hot water directly, whenever it is required, and does not need a hot water cylinder. Gas, oil and LPG boilers may be combination.

Regular boilers

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.

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

What is electric heating? 

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 give out the heat during the day. If you have storage heaters, you will probably have a hot water cylinder heated by one or two immersion heaters.

Electric storage heating is more common in flats, rented property, and in homes with no mains gas connection. It is one of the most expensive heating options in the UK, and it emits more carbon dioxide than most systems. It is also harder to control electric storage heaters than radiators, especially with older systems.

If you have a system like this, you may consider these energy saving 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 heating in the vast majority of houses in the UK. However, a number of alternative technologies can be used, or in addition to, including underfloor heating, solid fuel stoves, range cookers, open fires, electric fires and gas fires.