# What's giving off more heat: my computer, or me? **URL:** \ **Category:** Factual Questions\ **Created:** [July 23, 2010, 7:40pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758 "2010-07-23T19:40:43Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![VarlosZ](https://avatars.discourse-cdn.com/v4/letter/v/d78d45/32.png) [@VarlosZ](https://boards.straightdope.com/u/VarlosZ)\ **Post date:** [July 23, 2010, 7:40pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/1 "2010-07-23T19:40:43Z")
I was just wondering what’s a bigger factor in heating up my room: my own body (5’ 11", 190 lb.), or my desktop computer with it’s [22" monitor](http://reviews.cnet.com/lcd-monitors/hp-w2207h-22-monitor/1707-3174_7-32814504.html). I’m guessing that, whatever the answer, it’s not particularly close, but damned if I know what that answer is. Thanks in advance. ---
**Author:** ![Absolute](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@Absolute](https://boards.straightdope.com/u/Absolute)\ **Post date:** [July 23, 2010, 7:52pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/2 "2010-07-23T19:52:46Z")
Almost certainly your computer. Your monitor alone consumes 65 watts, and your computer around 100 watts at idle, perhaps up to 200 if you are doing something processor-intensive (watching a movie or Youtube video, for instance). An average human puts out about 100 watts, so your computer has you beat by almost a factor of 2, and maybe more. ---
**Author:** ![notsoheavyd3](https://avatars.discourse-cdn.com/v4/letter/n/85e7bf/32.png) [@notsoheavyd3](https://boards.straightdope.com/u/notsoheavyd3)\ **Post date:** [July 23, 2010, 8:06pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/3 "2010-07-23T20:06:09Z")
Well we could do the math. Pretty much 2000 Calories per day is average so that works out to 2000/24hrs /3600 = .023 calories per second. I went on to an online converter to convert that to joules and got 96.3 joules per second which is watts. So you use about 96~100 watts. My computer uses around 250~300 Watts so my computer uses more. ---
**Author:** ![SeaDragonTattoo](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeaDragonTattoo](https://boards.straightdope.com/u/SeaDragonTattoo)\ **Post date:** [July 23, 2010, 8:09pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/4 "2010-07-23T20:09:24Z")
Huh. Neat. I’m a light bulb. ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [July 23, 2010, 8:09pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/5 "2010-07-23T20:09:37Z")
Of course, efficient computers like laptops only consume a few tens of watts. And if you’re exercising you’ll consume an extra few hundred watts, maybe even a kilowatt for brief periods of high exertion. A top-class athlete can output 2 kw for a short duration, and that’s at something significantly less than 100% efficiency. ETA: Human muscle efficiency is the ballpark of 20-25%. So your world-class athlete could be consuming around 10 kw for short periods of time. So if you’re Lance Armstrong, using a laptop on a stationary bike, the result could be totally reversed. But **Absolute** is right for normal situations. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [July 23, 2010, 8:14pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/6 "2010-07-23T20:14:17Z")
But does energy consumed equal heat produced? ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [July 23, 2010, 8:26pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/7 "2010-07-23T20:26:18Z")
Yes, unless you’re storing some of that energy somehow, maybe by lifting heavy objects. But when those heavy objects fall down to where they were originally sitting their potential energy becomes heat again. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [July 23, 2010, 8:37pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/8 "2010-07-23T20:37:56Z")
I don’t understand that. If you move your arm, it takes a certain amount of energy, right? That energy is converted to movement. I thought only wasted energy becomes heat. Help me out here. ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [July 23, 2010, 8:42pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/9 "2010-07-23T20:42:27Z")
Right, so you temporarily convert chemical energy in your muscles into kinetic energy. But what happens to the kinetic energy when your arm stops? It’s lost to friction, impact, etc, which ultimately becomes heat. Everything turns into heat eventually. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [July 23, 2010, 8:56pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/10 "2010-07-23T20:56:15Z")
Ah!! Okay, makes sense. ---
**Author:** ![Baracus](https://avatars.discourse-cdn.com/v4/letter/b/2bfe46/32.png) [@Baracus](https://boards.straightdope.com/u/Baracus)\ **Post date:** [July 23, 2010, 8:57pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/11 "2010-07-23T20:57:46Z")
> [@lazybratsche](#): > > Yes, unless you’re storing some of that energy somehow, maybe by lifting heavy objects. Or gaining weight. ---
**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:** [July 23, 2010, 9:22pm UTC](https://boards.straightdope.com/t/whats-giving-off-more-heat-my-computer-or-me/547758/12 "2010-07-23T21:22:20Z")
As a general rule, _whenever_ the question is “where does the energy go?”, the answer is “heat”. > [@](#): > > And if you’re exercising you’ll consume an extra few hundred watts, maybe even a kilowatt for brief periods of high exertion. A top-class athlete can output 2 kw for a short duration, and that’s at something significantly less than 100% efficiency. For comparison, 1 horsepower is about 750 watts, so a human athlete can put out about two and a half horsepower (and not even just for a short time; Lance Armstrong (if you consider him human) can keep up something close to that rate for hours on end). What I get from this is that the standard horse is a slacker.