Lightbulb electricity usage

[dodgymanc]

I've heard that switching a lightbulb on and off uses up 20 mins of electricity, so it is best leaving it on if you are only going to be out of a room for a short period. Is this true, and does it differ between energy-efficient lightbulbs and normal one?

The reason i'm asking is because im on an electricity meter!

[Jay70]

I know this is true for some types of fluorescent tubes.

[Skids]

An ordinary light bulb will not use any extra power when turning on, like flourescent tubes do. As for worrying about leaving them on, if you're charged about 5p per unit by your electricity supplier (which I think is about average) an ordinary 40W bulb will cost 0.2p per hour to run, a 60W bulb will cost 0.3p per hour. If you left 10 60W bulbs on for 24 hours you'd have spent �0.72 on electricity.

[CT]

Stuff you you don't want to leave on are high power items, or higher power than your lights. If you want to switch something off, make it the tv (if your not watching it).

[Escher]

I suspect there will be some extra electricity used during turn on until some flow / heat / light equilibrium is reached, but I'd be surprised if it amounted to be any where near equivalent to 20 mins steady use (I'd guess less than 20 seconds).

Also, tturning the bulb on and off a lot will drastically shorten its life and you will have to buy more bulbs.

I suspect in the real world though, it is better to switch off, life is full of distractions and you are bound to not return as soon as you thought you would!

[Madge.B]

doggymanc energy saving bulbs are cheap in Tesco try this site for a free energy saving bulb

http://www.dochange.net/environment/ENV_display.jsp?pContentID=454&p_applic=CCC&pMenu0=43&p_service=Content.show&

also

http://www.easington.gov.uk/services/energy/lowenergylighting.asp

hope this helps

[adydb]

I also heard somewhere that boiling a full kettle (when you only need it for Two cups!!) uses the same energy as a 100 watt light bulb lit for 10 hours.

 

If dodgymanc is on a saving curve can anybody help on this?........was going to ask if anybody can throw any light on it, but I am being serious here!

[Madge.B]

I would put you on stand by adydb but it uses half the power best unplug you sorry! Well TVs do.

[Tim Baxter]

A TV like a PC only uses 30/40 watts on standby (less than a light bulb.

An incandescent lamp (conventional glowing thingy) does not suffer from being switched off/on and does not consume any more power when being switched on/off.

Fluorescents (which includes energy saving lamps) do suffer from being switched on and off, it shortens their life considerably.  So it becomes a trade off between switching off to conserve electricity and leaving it on to conserve life of the thingy.

What the maufacturers and govt don't teel you is that you must leave these energysavers on because startup uses lots of juice and switching off shortens their life and if they're switched on/off as in conventional lamps they work out more expensive.

Owzat?

[wellhungjock]

Not bad Tim! you got my vote. 

standby