# Energy conversion, please check my math
**URL:** https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304
**Category:** Factual Questions
**Created:** [November 26, 2003, 2:24am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304 "2003-11-26T02:24:58Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [November 26, 2003, 2:24am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/1 "2003-11-26T02:24:58Z")
I just want to compare the heat output of a 1500 W electric space heater and a 12,000 BTU KeroHeater.
Using kilowatts \* 3414 = BTU
I get 1.5 \* 3414 = 5121 BTU(s)
So the electric space heater puts out less then half then the Kero one. But when I googled btu and watts there seems to be a lot mentioned about Specific Heat and mass.
Just want to be sure that the above is correct.
Thanks.
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### Author:  [@KenGr](https://boards.straightdope.com/u/KenGr)
#### Post date: [November 26, 2003, 2:26am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/2 "2003-11-26T02:26:20Z")
Looks fine to me.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [November 26, 2003, 2:40am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/3 "2003-11-26T02:40:27Z")
The only problem is that the BTU is a unit of _energy_, while the watt is a unit of _power_. Energy is power multiplied by time. Your result of 5121 is in BTU/hr.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [November 26, 2003, 2:42am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/4 "2003-11-26T02:42:06Z")
Forgot to add that air conditioners and heaters _are_ rated in BTU/hr, so your result is correct. Just the units were incorrect.
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### Author:  [@Achernar](https://boards.straightdope.com/u/Achernar)
#### Post date: [November 26, 2003, 6:02am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/5 "2003-11-26T06:02:00Z")
[Google calculator agrees](http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=1500+watts+in+BTU%2Fhr&btnG=Google+Search), or pretty close to it anyway.
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### Author:  [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)
#### Post date: [November 26, 2003, 6:22am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/6 "2003-11-26T06:22:01Z")
> [@](#):
>
> \*Originally posted by Q.E.D. \*
> **The only problem is that the BTU is a unit of _energy_, while the watt is a unit of _power_.**
Which is a reason it irks me to see furnaces, stoves, cookers, gas grills, and heaters advertised simply as “50,000 Btu!”, “100,000 Btu!” and so forth. And if you try to explain to the salesman why the advert is misleading, he smiles and acts like he’s going to pat you on the head and send you on your way. :rolleyes:
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### Author:  [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)
#### Post date: [November 26, 2003, 9:00am UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/7 "2003-11-26T09:00:48Z")
Yep my calculator agrees too:
[http://www.1728.com/convenrg.htm](http://www.1728.com/convenrg.htm)
Notice too that there are 6 different kinds of BTU definitions. Maybe more for all I know.
Isn’t it high time that the Metric System (or System Internationale) becomes _the_ standard ? Aren’t we all tired of converting furlongs to nautical miles, etc ?
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [November 26, 2003, 12:07pm UTC](https://boards.straightdope.com/t/energy-conversion-please-check-my-math/215304/8 "2003-11-26T12:07:30Z")
> [@](#):
>
> \*Originally posted by Una Persson \*
> \*\*Which is a reason it irks me to see furnaces, stoves, cookers, gas grills, and heaters advertised simply as “50,000 Btu!”, “100,000 Btu!” and so forth. And if you try to explain to the salesman why the advert is misleading, he smiles and acts like he’s going to pat you on the head and send you on your way. :rolleyes: \*\*
I have a similar pet peeve when it comes to car stereo amps when they list “RMS Power.” Problem is, _no one_ mathematically computes the RMS of a power signal. It would be meaningless to do so…