Power factor for lamps
According to BRE’s The essential guide to retail lighting:
The term ‘power factor’ is ‘…A measure of the phase difference between the voltage and current in an alternating current (AC) supply. For lamp types other than incandescent, the voltage and current waveforms are not exactly in phase with one another: thus the volts multiplied by the amperes in the circuit may be higher than the Watts. In such cases, the Watts represent the active power, and the volts multiplied by the amperes represent the apparent power. The power factor is the ratio of the absolute value of the active power to the apparent power. Ideally, the power factor should be as close to unity as possible. A low value of the power factor increases the current load and the energy consumption. Most high-wattage lamp circuits are designed to have a power factor greater than 0.85.’
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Ballast or control gear.
- Colour appearance.
- Daylight benefits in healthcare buildings.
- Daylight factor.
- Daylight lighting systems.
- Dichroic reflector.
- Discharge lamp.
- Extra-low voltage lamps.
- General lighting v task lighting.
- Illuminance.
- Lamp.
- Lamp efficacy.
- Light pollution.
- Lighting.
- Lighting energy numeric indicator LENI.
- Lighting of construction sites.
- Luminaire efficacy.
- Rights to light.
- The Future of Electricity in Domestic Buildings.
- The UK’s low-carbon future is increasingly electric.
Featured articles and news
Sustainable Urban Drainage and Biodiversity
Awards for champions of these interconnected fields now open.
Microcosm of biodiversity in balconies and containers
Minor design adaptations for considerable biodiversity benefit.
CIOB student competitive construction challenge Ireland
Inspiring a new wave of Irish construction professionals.
Challenges of the net zero transition in Scotland
Skills shortage and ageing workforce hampering Scottish transition to net zero.
Private rental sector, living standards and fuel poverty
Report from the NRH in partnership with Impact on Urban Health.
.Cold chain condensing units market update
Tracking the evolution of commercial refrigeration unit markets.
Attending a conservation training course, personal account
The benefits of further learning for professsionals.
Restoring Alexander Pope's grotto
The only surviving part of his villa in Twickenham.
International Women's Day 8 March, 2025
Accelerating Action for For ALL Women and Girls: Rights. Equality. Empowerment.
Lack of construction careers advice threatens housing targets
CIOB warning on Government plans to accelerate housebuilding and development.
Shelter from the storm in Ukraine
Ukraine’s architects paving the path to recovery.
BSRIA market intelligence division key appointment
Lisa Wiltshire to lead rapidly growing Market Intelligence division.
A blueprint for construction’s sustainability efforts
Practical steps to achieve the United Nations Sustainable Development Goals.
Timber in Construction Roadmap
Ambitious plans from the Government to increase the use of timber in construction.
ECA digital series unveils road to net-zero.
Retrofit and Decarbonisation framework N9 launched
Aligned with LHCPG social value strategy and the Gold Standard.
Competence framework for sustainability
In the built environment launched by CIC and the Edge.
Institute of Roofing members welcomed into CIOB
IoR members transition to CIOB membership based on individual expertise and qualifications.
Join the Building Safety Linkedin group to stay up-to-date and join the debate.
Government responds to the final Grenfell Inquiry report
A with a brief summary with reactions to their response.