- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 17 Oct 2018
A kilowatt hour (kWh or kW h) is a unit of energy that is equivalent to 1,000 watts (1 kW) of energy being transmitted or used for one hour. The kilowatt hour is commonly used by utility companies for pricing, calculating and communicating electricity energy bills to consumers.
For example, a 100 W light bulb would take 10 hours to consume 1 kWh of energy. A 50 W electrical appliance that is used at a constant rate for 20 hours would use 1 kWh of energy. A 2 kW electrical appliance would use 1 kWh in 30 minutes.
To calculate the cost of running an electrical appliance, the power consumption in kWh is multiplied by the price per kWh. The unit price of electricity often varies depending on the rate of consumption, the time of day, and the location.
 Related articles on Designing Buildings Wiki
Featured articles and news
When is there a right to light, and what happens if it is obstructed?
What would the nationalisation of economic infrastructure mean for GB?
A new guide to improving value by reducing design error.
We've reached 80,000 page views a day and 10,000 registered users. Why not join them?
A masterplan is a framework within which a location is encouraged to develop or change. Read our introductory article.
New consultation announced on a specialist Housing Court to settle landlord-tenant disputes.
ICE responds to a transport consultation advising the government to make decisions enabling more inclusive cities.
BRE and Loughborough University complete first phase refurbishment of demonstration home.
How the risk of collapse of fibrous plaster ceilings is being addressed in theatres.
If you’re a great writer and have practical experience of the construction industry, it could be you.
Frustrated by long documents or technical jargon? Put off by sign-up forms or costs? Take this 5 min survey to help improve construction knowledge.