# Is an incandescent bulb efficient in winter? **URL:** \ **Category:** Factual Questions\ **Created:** [November 16, 2008, 4:25pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003 "2008-11-16T16:25:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![kapntoad](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@kapntoad](https://boards.straightdope.com/u/kapntoad)\ **Post date:** [November 16, 2008, 4:25pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/1 "2008-11-16T16:25:25Z")
Considering that an incandescent bulb wastes something in the neighborhood of 75 percent of its output in heat, it’s very inefficient _at lighting_. When it’s cold out and I’m heating my house, that energy isn’t being wasted; it’s assisting my furnace. An excess of heat from the bulb means a tiny fraction of time the furnace isn’t running. In fact, the furnace has energy waste in the form of noise. Switching my compact fluorescents for incandescents in the winter may actually be improving my carbon footprint. Maybe. If all the energy going into the bulb is coming out either as light (good!) or heat (good!), is an incandescent bulb wasteful at all? ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [November 16, 2008, 4:46pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/2 "2008-11-16T16:46:14Z")
It’s fairly efficient as a light + heat source (not so much if you only want it for one or the other), but electricity is probably more expensive than whatever you’re using to power your furnace. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [November 16, 2008, 4:49pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/3 "2008-11-16T16:49:34Z")
> [@CookingWithGas](#): > > It’s fairly efficient as a light + heat source (not so much if you only want it for one or the other), but electricity is probably more expensive than whatever you’re using to power your furnace. Nice user name/answer combo. Good answer too. A natural gas furnace is not only cheaper than electricity but is also more environmentally friendly than the coal that was probably burned to generate the electricity. ---
**Author:** ![Ice\_Cream\_Man](https://avatars.discourse-cdn.com/v4/letter/i/9f8e36/32.png) [@Ice\_Cream\_Man](https://boards.straightdope.com/u/Ice_Cream_Man)\ **Post date:** [November 16, 2008, 4:50pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/4 "2008-11-16T16:50:58Z")
Yeah, along the lines of what CookingWithGas said: If you’re trying to have a smaller carbon footprint you not only have to consider how wasteful the bulb would be but also the electricity you get it from. How much carbon is created by the generating plant? How much energy is lost between the plant and your house? I don’t know the answers to those questions but they definitely are important. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 16, 2008, 5:09pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/5 "2008-11-16T17:09:53Z")
> [@kapntoad](#): > > In fact, the furnace has energy waste in the form of noise. What do you mean by this? That the _sound_ that the furnace makes is reducing it’s efficiency? If so, you are worried about the wrong thing - the amount of power in sound is truly negligible. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 16, 2008, 5:59pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/6 "2008-11-16T17:59:33Z")
> [@](#): > > What do you mean by this? That the sound that the furnace makes is reducing it’s efficiency? If so, you are worried about the wrong thing - the amount of power in sound is truly negligible. Especially considering that most of that sound gets turned back into heat, anyway. Any sound that you can’t hear from outside of the house got absorbed somewhere inside. Everything always gets converted to heat, in the end. But even if your furnace were so loud that you could hear it a block away, that’s still not all that much energy. ---
**Author:** ![aerodave](https://avatars.discourse-cdn.com/v4/letter/a/f08c70/32.png) [@aerodave](https://boards.straightdope.com/u/aerodave)\ **Post date:** [November 16, 2008, 6:09pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/7 "2008-11-16T18:09:14Z")
> [@CookingWithGas](#): > > It’s fairly efficient as a light + heat source (not so much if you only want it for one or the other), but electricity is probably more expensive than whatever you’re using to power your furnace. Unless, of course, he’s using electricity to heat his home. My guess is probably not given his location. But in general, there are people who have electric central heat. I had two apartments in college with electric forced air heat. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 16, 2008, 9:41pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/8 "2008-11-16T21:41:13Z")
If you are forced to use electricity to heat your home, in mild climates, a [heat pump](http://en.wikipedia.org/wiki/Heat_pump) is the most efficient way to go. A heat pump can provide up to 4x the heating as an electrical resistance heater of the same wattage. ---
**Author:** ![kapntoad](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@kapntoad](https://boards.straightdope.com/u/kapntoad)\ **Post date:** [November 16, 2008, 9:43pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/9 "2008-11-16T21:43:43Z")
> [@CookingWithGas](#): > > It’s fairly efficient as a light + heat source (not so much if you only want it for one or the other), but electricity is probably more expensive than whatever you’re using to power your furnace. You’re right, of course. I completely missed the gas vs. electric component. > [@beowulff](#): > > What do you mean by this? That the _sound_ that the furnace makes is reducing it’s efficiency? If so, you are worried about the wrong thing - the amount of power in sound is truly negligible. Sure, it’s negligible, but my point was that it would make it (even slightly) less efficient than the light bulb. (Assuming any noise energy makes it out of the house.) That was before CWG pointed out my energy source blunder. Thanks for the wisdom, all. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 16, 2008, 9:56pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/10 "2008-11-16T21:56:10Z")
> [@kapntoad](#): > > You’re right, of course. I completely missed the gas vs. electric component. > > Sure, it’s negligible, but my point was that it would make it (even slightly) less efficient than the light bulb. (Assuming any noise energy makes it out of the house.) That was before CWG pointed out my energy source blunder. > > Thanks for the wisdom, all. Believe me, there is less energy in the sound escaping your house than there is an any light escaping your house through a window… ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [November 16, 2008, 10:19pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/11 "2008-11-16T22:19:40Z")
There is also the location of the ‘waste’ heat from the bulb to consider. Most bulbs are located near the ceiling of the room, and heat rises, so the excess heat from the bulb is just warming up the ceiling, not the occupants of the room. Some may radiate back into the room, or into the upstairs floor if it’s a 2-story house, but it’s far less efficient at heating your house than, say, an electrical baseboard heater. But your basic point is correct: the bulb is less inefficient in winter because the waste heat is useful. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [November 17, 2008, 3:08am UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/12 "2008-11-17T03:08:13Z")
> [@kapntoad](#): > > Switching my compact fluorescents for incandescents in the winter may… …be necessary to get good lighting. The flouresecents tend to give less light when they’re switched on if they’re cold. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [November 17, 2008, 7:02am UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/13 "2008-11-17T07:02:06Z")
> [@Gary\_T](#): > > …be necessary to get good lighting. The flouresecents tend to give less light when they’re switched on if they’re cold. But that is generally true only when they are below 35ºF. If the OP is keeping his house at this temperature – barely above freezing – he’s probably got other things to worry about. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [November 17, 2008, 12:07pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/14 "2008-11-17T12:07:31Z")
The efficiency of the bulb remains the same. Your desire for the heat product just changes, if you need to heat your house instead of cool it. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [November 17, 2008, 3:29pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/15 "2008-11-17T15:29:51Z")
I am mostly heated by electricity (it switches to oil below -12C) and all the electricity in Quebec is hydro-electric so it matters not in the heating season (which is nearly 8 months long) whether I use CF bulbs or not. In fact, rather than turn up the heat I turn on the lights in my bathroom five minutes before I take a shower and it really makes a difference. Incidentally, I pay under 5c/kwh when the temperature is above -12C and about triple that when it is below. ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [November 17, 2008, 4:51pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/16 "2008-11-17T16:51:50Z")
> [@kapntoad](#): > > In fact, the furnace has energy waste in the form of noise. While true, this is negligible. A much bigger source of waste for a furnace is the heat that is lost along with the exhaust gases, but that still isn’t very much (\< 10% for a modern furnace). As other posters have mentioned, you’re still better off burning it at the final destination than burning it at a power plant and transmitting electricity via power lines, which is why a 90% efficient gas furnace beats a 100% efficient electric heater. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 17, 2008, 5:16pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/17 "2008-11-17T17:16:27Z")
> [@](#): > > As other posters have mentioned, you’re still better off burning it at the final destination than burning it at a power plant and transmitting electricity via power lines, which is why a 90% efficient gas furnace beats a 100% efficient electric heater. Or even a more-than-100% efficient heat pump. ---
**Author:** ![The\_Scrivener](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@The\_Scrivener](https://boards.straightdope.com/u/The_Scrivener)\ **Post date:** [November 17, 2008, 5:24pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/18 "2008-11-17T17:24:07Z")
Depending on the size and layout of your place, you might well be better off task-heating a room or bathroom either by turning on more lights or using a portable space heater, as opposed to heating the whole place or turning up the thermostat. Using a heater should be more cost-effective per therm, however, because its output can be better aimed and because its heating element is more durable (and thus cost-effective) than the miniscule filaments in incandescent light bulbs. But that’s splitting a pretty thin dime, whereas one of the distinct pleasures of a northern winter is having enjoying a bright, cheery home (while bundled in warm, fuzzy sweaters and socks). Here’s my tip to warming up for less while keeping the thermostat very low: when I’m sedentary and cold, and don’t want to actually drink or eat anything, I’ll heat up a mug’s worth of water (not to a full boil; that’s too hot) and just cradle it in my hands when I’m at the computer or watching TV. This works and it’s cheap and environmentally responsible. ---
**Author:** ![troub](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troub/32/14802_2.png) [@troub](https://boards.straightdope.com/u/troub)\ **Post date:** [November 17, 2008, 6:29pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/19 "2008-11-17T18:29:06Z")
> [@The\_Scrivener](#): > > I’ll heat up a mug’s worth of water. Since we’re talking fine minutae anyway. . .microwave or gas stove? ---
**Author:** ![The\_Scrivener](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@The\_Scrivener](https://boards.straightdope.com/u/The_Scrivener)\ **Post date:** [November 17, 2008, 6:44pm UTC](https://boards.straightdope.com/t/is-an-incandescent-bulb-efficient-in-winter/473003/20 "2008-11-17T18:44:41Z")
> [@troub](#): > > Since we’re talking fine minutae anyway. . .microwave or gas stove? I’ve always used my gas stove, but I suppose the microwave would do just as well (the coal-based and transmission inefficiencies of electricity notwithstanding), provided the mug was truly microwave-safe. But I’ve found that a lot of so-called m.-safe items aren’t, so take care you don’t end up 'twixt a mug and a hot plate. I forgot to mention one advantage of cradling a mug of hot water: the rising cloud of steamy vapor, and how that can help you cope with sinus problems exacerbated by excessively dry air, etc.