Micro combined heat and power (micro-CHP) boilers generate electricity for use in the home. However, the by-product of the generation of this electricity is used to provide heat and hot water like a conventional boiler.

What is micro-CHP heating?

The technology of micro combined heat and power (micro-CHP) generates heat and electricity from the same source at the same time. They are designed for use in individual homes or buildings.  

Heat is the main output of a micro-CHP system, while electricity is also generated. In domestic appliances, this works at a typical ratio of approximately 6:1.*1

How does micro-CHP boiler work?

Despite being powered by mains gas or LPG, micro-CHP systems are considered low carbon technology because they are more efficient than getting electricity from the grid or burning fossil fuels for heat.

Similar in size and appearance to regular domestic boilers, micro-CHP systems can also be floor standing or wall hung.

The only real difference between a micro-CHP system to a standard boiler is that they are able to generate electricity at the same time as heating water.

Types of systems available

The three main micro-CHP systems generate electricity using different technology.

Stirling engine micro-CHP

Despite the principal of the Stirling engine being well established, this technology is fairly new to the market.

This type of system produces a relatively small electrical output in relation to the heat, approximately 6:1, but this isn’t seen as a problem when applied to micro-CHP.

Internal combustion engine CHP

Despite this being the most proven technology and offering a higher electrical efficiency than a Stirling engine, these are not currently available for the domestic market.

These are similar to truck diesel engines that have been modified to function on heating oil or natural gas and connected to an electrical generator. The heat is taken from the cooling water and exhaust manifold of the engine.

Fuel cell CHP technology

This system works by taking energy from fuel at a chemical level rather than burning it. This technology is very new to the market and is not widely available to consumers as it is still at the developmental stage.

Efficiency of micro-CHP boilers

A micro-CHP system can be very effective with up to 92% efficiency.*2 More energy is generated from the fuel when it is burned so it needs less gas to operate. Because the micro combined heat and power generates electricity as well as heat, this contributes to the overall energy needed to power your home or property.

Costs and savings

With all renewable energy solutions, a key factor to consider is the cost of purchase, installation and what it could save you in the long run.

Average cost of a CHP boiler

A typical micro combined heat and power boiler will cost between £5,000 and £7,000.*3 A HIES accredited installer will be able to advise you in greater detail.

How much could you save?

Overall, the increased efficiency of a micro combined heat and power boiler over a conventional gas boiler should make it a good investment over the longer term, and newer technologies such as ‘flow boilers’ which are competitively priced against a gas combination boiler. Care needs to be taken when comparing boilers and deals as there can be energy supplier tie-ins with some products.    

Using an installation company

Purchasing a micro combined heat and power boiler is a considerable investment, so it is vital that you choose a reputable installer for your project.

All HIES accredited installers are continually vetted in many areas in order to give consumers trust, confidence and peace of mind.

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