# Amount of heat produced by a human body **URL:** \ **Category:** Factual Questions\ **Created:** [July 19, 2007, 4:58pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413 "2007-07-19T16:58:05Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![athelas](https://avatars.discourse-cdn.com/v4/letter/a/5e9695/32.png) [@athelas](https://boards.straightdope.com/u/athelas)\ **Post date:** [July 19, 2007, 4:58pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/1 "2007-07-19T16:58:05Z")
When I become dictator of the world, I plan to be an environmentally friendly one. Therefore, to the extent that it is possible, I want to use the body heat of the prisoners in my dungeons to heat my Fortress of Evil(TM.) How much heat is produced by an average human at rest and during vigorous exercise? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [July 19, 2007, 5:31pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/2 "2007-07-19T17:31:11Z")
Roughly 100 watts at rest; more if you make them work hard. ---
**Author:** ![Hello\_Again](https://avatars.discourse-cdn.com/v4/letter/h/85e7bf/32.png) [@Hello\_Again](https://boards.straightdope.com/u/Hello_Again)\ **Post date:** [July 19, 2007, 5:32pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/3 "2007-07-19T17:32:59Z")
Yeah, that’s exactly what I heard last night on the history channel (they were looking at underground bunkers beneath Berlin). The host commented that the bunkers were cold, and the expert said a person gives off the same heat as a 100 watt bulb, and with several thousand people in the bunker complex it was really hot. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [July 19, 2007, 6:00pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/4 "2007-07-19T18:00:21Z")
Related thread: [Heat from candles](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=117206) A person using 2500 Calories per day puts out 121 watts. ---
**Author:** ![Mindfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindfield/32/19759_2.png) [@Mindfield](https://boards.straightdope.com/u/Mindfield)\ **Post date:** [July 19, 2007, 6:08pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/5 "2007-07-19T18:08:29Z")
_1.21 Gigawatts??_ Oh! You said … ah, sorry. 121 watts sounds like an awful lot though. Is this comparable to a 120 watt light bulb, for example? Because those things get _way_ too got to touch. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [July 19, 2007, 6:14pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/6 "2007-07-19T18:14:51Z")
[QUOTE=Mindfield] _1.21 Gigawatts??_ Oh! You said … ah, sorry. 121 watts sounds like an awful lot though. Is this comparable to a 120 watt light bulb, for example? Because those things get _way_ too got to touch. [/QUOTE] But what about compared to a 120 watt light bulb at a distance of 1 foot? Sure, you’d feel some radiation, but it’d feel about…hmmm, prolly about as hot as placing your hand right next to but not touching a person come to think of it! ---
**Author:** ![Mikemike2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikemike2/32/305_2.png) [@Mikemike2](https://boards.straightdope.com/u/Mikemike2)\ **Post date:** [July 19, 2007, 6:27pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/7 "2007-07-19T18:27:24Z")
I recently went to a Stampede party in a hotel banquet room with hundreds of people. When we got there the room was freezing because of the air conditioning. There were bands and dancing and before long the room was broiling. People in crowds generate a lot of heat. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 19, 2007, 6:30pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/8 "2007-07-19T18:30:21Z")
The lightbulb seems excessively hot because it’s concentrated into such a small volume and/or surface area compared to a human. ---
**Author:** ![Pepinator](https://avatars.discourse-cdn.com/v4/letter/p/90db22/32.png) [@Pepinator](https://boards.straightdope.com/u/Pepinator)\ **Post date:** [July 19, 2007, 6:48pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/9 "2007-07-19T18:48:51Z")
A useful table of heat output from people with various activity levels can be found at [Human Heat Gain](http://www.engineeringtoolbox.com/persons-heat-gain-d_242.html) For the purposes of your Fortress of Evil ™, you’re really only concerned with the sensible heat. The latent heat is tied into moisture content of the air, but doesn’t directly impact air temperature. ---
**Author:** ![Cabin\_Fever\_1](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cabin_fever_1/32/2908_2.png) [@Cabin\_Fever\_1](https://boards.straightdope.com/u/Cabin_Fever_1)\ **Post date:** [July 19, 2007, 6:54pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/10 "2007-07-19T18:54:01Z")
Can anyone tell me if this [site graphic](http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/coobod.html) is reasonably accurate? I have no clue. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [July 19, 2007, 10:21pm UTC](https://boards.straightdope.com/t/amount-of-heat-produced-by-a-human-body/412413/11 "2007-07-19T22:21:10Z")
I used to know someone who worked in a standards laboratory. Every day, when he arrived at work, he would unscrew a 100 watt light bulb. He screwed it back in when he left. This was supposed to help keep the air temperature constant.