Micro-CHP
At a large scale, combined heat and power (CHP sometimes referred to as cogeneration) is generally a process in which the heat that is created as a by-product of power generation is captured and used rather than being wasted. Typically, a gas-powered turbine or reciprocating engine is used to produce electricity, and the heat recovered is used for local water or space heating, or to support an industrial process.
Microgeneration (or micro-generation) is the local production of electricity and/or heat on a very small scale. Typically, microgeneration has an output of under 45kW for heat and under 50kW for electricity.
Micro-CHP or micro combined heat and power is the small-scale generation of heat and electricity from a single energy source.
Micro-CHP is becoming more common in domestic buildings, where it can be installed as direct replacement for gas-fired boilers as micro-CHP units (sometimes referred to as CHP boilers) are similar in size and shape to conventional domestic boilers and can be floor standing or wall hung.
The main output of domestic micro-CHP units is generally heat, with some electricity generation, in the ratio of around 6:1. Typically, domestic units can generate up to 1 kW of electricity. This can be used to power the dwelling, or sold back to the grid.
Currently, domestic scale micro CHP units tend to generate electricity using a stirling engine. The boiler element of the unit heats water for central heating and to provide a hot water supply, and the ‘waste’ heat from the boiler heats an enclosed working gas such as helium in the stirling engine. The gas expands and contracts as it is heated and cools, pushing a magnetic piston up and down within copper coil windings, generating an alternating current.
Domestic micro CHP units tend to be powered by natural gas or by liquefied petroleum gas (LPG) and because of their efficiency they are considered to be a low-carbon technology. In the future, they may use bio-fuels, and so might be considered to be a ‘renewable’ technology. They may also develop to adopt fuel cell CHP technology which may be more efficient than gas turbines or stirling engines.
Consumers who generate their own electricity from a renewable or low-carbon source can qualify for a payment known as the feed-in tariff (FIT) for each unit of electricity generated. Consumers can also qualify for an ‘export tariff’ by selling surplus electricity back to their supplier. Micro-CHP is an allowable technology, qualifying for the feed in tariff.
[edit] Related articles on Designing Buildings Wiki.
- CHP.
- Condensing boiler.
- District energy.
- Domestic micro-generation.
- Feed in Tariff.
- Fuel cell.
- Future of electricity in domestic buildings.
- Green Deal.
- Microgeneration.
- Microgeneration certification scheme.
- Micro-grid.
- On-site generation of heat and power.
- Smart Export Guarantee SEG.
- Solar photovoltaics.
- Solar thermal panels.
- Types of boiler.
Featured articles and news
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.