Best Answer

This used to be a valid question with older fluorescent fixtures, but not anymore. A light that is off doesn't use power and it doesn't use extra power when turning on, so turn it off to save power. It depends what you want to consider. If you throw bulb life into the mix (most bulbs fail due to thermal cycle fatigue) then you might be better off leaving the light on. Incandescent lamps have substantially higher inrush current before the filament heats up. This probably does not amount to enough to significantly increase the operating cost, however it reduces the life of the bulb. Incandescent light failure is almost always when cycling the lamp on.


It's always best to turn the lamp off when it isn't needed. The extra power from the inrush occurs over an extremely short time and the energy used is minimal.

On 240 volts suppose the inrush is 10 amps for 1/20 second (it is probably much less), the energy of the inrush is 2400/20 watt-seconds, 120 watt-seconds, which is the same as leaving it switched on for 1.2 seconds.

On that basis you should turn it off if you plan to be outside that room for 2 seconds or more.

User Avatar

Wiki User

โˆ™ 2015-07-16 18:10:15
This answer is:
User Avatar

Add your answer:

Earn +5 pts
Q: Is it cheaper to leave a light burning for several hours than to turn it off and on several times?
Write your answer...

Related Questions

Is it cheaper to leave the temperature stable?

Is it cheaper to leave your gas furnace setting at 68 degrees in the winter

What is the best way to thaw frozen chicken breasts?

Leave it out for several hours or overnight in a bowl

How long can sushi sit at room temp?

Sushi can sit for several hours. But, i wouldn't leave it out for more than 3-5 hours.

Can you peel and cut white potatoes and leave them sit in water for several hours before cooking them?

Sure. If more than a few hours, refigerating would be best.

Does burning cotton leave ash?


How long should you leave a candle burning?

I personally think about 4 hours would be the most safe, that is what all the safety tips say. But if you want to go on the line, the absolute longest would be 7 hours.

Is it cheaper to leave a fluorescent light on or switch it on and off?

Always cheaper to switch it off and on rather than leaving it on.

Should you reheat pork?

No, because the germs will attack it if it is allowed to heat twice. This might work, however, if you leave it for several hours.

How many hours do you need to get maternity leave?

How many hours do you need to get maternity leave?

Is it safe to leave fireplace burning at night?

No. Never.

Does burning orange peels leave ash?


What is the duration of When We Leave?

The duration of When We Leave is 1.98 hours.

What does magnesium ribbon leave after burning?

MgO, Magnesium oxide.

Can you use vaseline on face?

You can - but be careful. If you are planning to leave it on your face for several hours it can clog your pores. Your pores should be able to breathe. Hope this helps.

What is the meaning of did you Leave that light burning for me?

To leave a light burning for someone means expecting someone to come home or visit. Its a term of endearment to show someone you were expecting them, or hoping they would come.

What hours should you leave the light on for fish?

Leave the light on during daylight hours, and turn it off at nightime.

How long can you leave raw fish out of refrigerator?

You Shouldn't leave it out for to long but about 6 hours if in package if not about 3 hours

Does it hurt a pickup to leave it running for several hours?

Just normal wear but you should avoide extensive run times since engine life is not indefinate no of hours and extrememly taxing on cooling system when not moving

What did the KKK leave on people porches?

burning crosses.the Christian symbol

Why did the Calgary Flames leave Atlanta?

Because they finished burning up.

Does hydrogen leave residue on burning?

Nothing is left because hydrogen is an element, from which only water is formed when burning (explosively) with oxygen.

What is the duration of Time to Leave?

The duration of Time to Leave is 1.35 hours.

What is the duration of Leave Them Laughing?

The duration of Leave Them Laughing is 1.5 hours.

What is the duration of Leave Her to Heaven?

The duration of Leave Her to Heaven is 1.83 hours.

How do you reset computer on a 1989 Mercury Cougar?

Disconnect the vehicles battery. Leave it unhooked for several hours. Reconnect the battery. This should reset the 1989 cougars computer.