Naturally it depends how many you have, how long you keep them on, what their rating (wattage) is, and what electricity tariff you're on.
A typical 50W halogen bulb switched on for 1 hour will use 50 "watt hours", or one twentieth of a kilowatt hour. A kilowatt hour costs about 14p (not including standing charge). So it costs about 0.7p for every hour that each bulb is turned on.
To complicate things, there is also the cost of replacement when they blow. Halogens are cheap to replace but in theory need to be replaced more often than LEDs. However in my experience that depends very much on the LED manufacturer. |