# Which one uses more electricity?



## Acer Rubrum (Nov 23, 2011)

This question isn't really about alternative energy but I thought that you guys would still be the best ones to ask.
Which heating method would run my electric bill up the most? This is for an indoor animal enclosure.
(1) Turning on 5 of the 250 watt incandescent heat bulbs for them to lay under
or
(2) Running a heat/ac unit that is 11,600 BTU Electric Heat, 230/208 Volt, 13/2 amps
Thank you in advance.


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## wy_white_wolf (Oct 14, 2004)

If they are heating the same area to the same temperature they should use the same.

More likely though, the bulbs will be heating a smaller area. I would guess they would use less. But since they don't have any temperature regulation it'd only a guess.

WWW


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## Harry Chickpea (Dec 19, 2008)

Apples and oranges. One is radiant heat, the other convection. The heater is 3400 watts plus minor losses, the five lamps 1250 watts, but the heater is unlikely to run continuously due to thermostatic control.

In a completely open pen, the lamps are a better choice. In an enclosed space the heater MAY be a better choice. I'd prefer the lamps because they allow the choice. Animals become acclimatized and too much heat may disrupt that.


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## Acer Rubrum (Nov 23, 2011)

Harry Chickpea, I was wondering how many watts the electric heater used. How do you find out that it uses 3400 watts? Is there a mathmatical formula? Thank you.


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## Harry Chickpea (Dec 19, 2008)

BTU per hour and watts per hour are both units of total energy. 1 Watt hour is approximately 3.4 BTUs per Hr. One is generally a measurement of electricity, the other of heat. With any electric heat source other than a heat pump (which moves ambient heat rather than converting it from electric power) the coefficient of performance is exactly one. It is a basic law of physics.


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## Acer Rubrum (Nov 23, 2011)

Thank you so much for the mathmatical breakdown!


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## SolarGary (Sep 8, 2005)

Acer Rubrum said:


> This question isn't really about alternative energy but I thought that you guys would still be the best ones to ask.
> Which heating method would run my electric bill up the most? This is for an indoor animal enclosure.
> (1) Turning on 5 of the 250 watt incandescent heat bulbs for them to lay under
> or
> ...



If the AC unit uses a heat pump for both AC and heating, then it will be quite a bit more efficient than the straight resistance heater lamps.
Like this AC unit: http://www.ptacunits.com/index.php?...kJCotFv7t1xguqfjeaGzdxXoRlDZo3UI0caAk-18P8HAQ
This one says it has an EER of 9.5, which translates to a COP of 9.5/3.41 = 2.78, or an efficiency of 278% -- compared to 100% for resistance heating.

Gary


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