Circuit-watt
According to the Domestic Building Services Compliance Guide published by HM Government in 2013, the term ‘circuit-watt’ refers to:
| The power consumed in lighting circuits by lamps, and where applicable, their associated control gear (including transformers and drivers) and power factor correction equipment. |
'Lamp lumens per circuit-watt is the total lamp lumens summed for all luminaires in the
relevant areas of the building, divided by the total circuit-watts for all the luminaires.'
'Luminaire lumens per circuit-watt is the (lamp lumens x LOR) summed for all luminaires
in the relevant areas of the building, divided by the total circuit-watts for all the luminaires.'
Ref Non-domestic Building Services Compliance Guide For Scotland, 2015 Edition v1.1, published by the Scottish Government, Building Standards Division in April 2018.
NB Approved Document L, Conservation of fuel and power, Volume 1: Dwellings, 2021 edition incorporating 2023 amendments, suggests that circuit-watt: ‘Refers to the power consumed in lighting circuits by lamps and, where applicable, their associated control gear (including transformers and drivers) and power factor correction equipment.’
[edit] Related articles on Designing Buildings
- Daylight lighting systems.
- Domestic building services compliance guide.
- Fused spur.
- General lighting v task lighting.
- Health and wellbeing impacts of natural and artificial lighting.
- Lighting and energy efficiency.
- Lighting energy numeric indicator.
- Non-domestic building services compliance guide.
- Space classifications for lighting controls.
- Specialist process lighting.
- The impact of lighting in retail design.
- Watt.
Featured articles and news
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Many resources for visitors aswell as new features for members.
Using technology to empower communities
The Community data platform; capturing the DNA of a place and fostering participation, for better design.
Heat pump and wind turbine sound calculations for PDRs
MCS publish updated sound calculation standards for permitted development installations.
Homes England creates largest housing-led site in the North
Successful, 34 hectare land acquisition with the residential allocation now completed.
Scottish apprenticeship training proposals
General support although better accountability and transparency is sought.
The history of building regulations
A story of belated action in response to crisis.
Moisture, fire safety and emerging trends in living walls
How wet is your wall?
Current policy explained and newly published consultation by the UK and Welsh Governments.
British architecture 1919–39. Book review.
Conservation of listed prefabs in Moseley.
Energy industry calls for urgent reform.
Heritage staff wellbeing at work survey.
A five minute introduction.
50th Golden anniversary ECA Edmundson apprentice award
Showcasing the very best electrotechnical and engineering services for half a century.
Welsh government consults on HRBs and reg changes
Seeking feedback on a new regulatory regime and a broad range of issues.
CIOB Client Guide (2nd edition) March 2025
Free download covering statutory dutyholder roles under the Building Safety Act and much more.