tiny efficient under desk heater?

6 years ago

last modified: 6 years ago

I'm looking for tiny space heater for under my desk. really efficient / low power. all I want this to do is supplement -- I really don't want to crank up my house thermostat just for one person all day. need just a little more heat when I'm sitting at my desk. I don't like the heaters that blow air though, I feel cold as soon as they turn off. would rather have something like a flat, low watt radiator.

I'm looking at units like this on amazon, but the bad reviews are scaring me off. they all seem really cheaply made. does anyone use something similar they can recommend?

Featured Answer

kaseki

6 years ago

Electric heaters are 100% efficient because all of the power consumed has to go someplace, and the only place available is the air around or passing through the device or some nearby object that it might radiate heat to.

For low power, compare the power levels of various devices that might be found in a big-box store (or Amazon). The example at 150W may be enough depending on your needs, not determinable from this distance.

Whether the desk is on your property or that of a commercial entity may affect what you are allowed to do.

For best radiant heat reliability vs. cost, just hang a 150W lamp under the desk, away from your legs. Use an industrial light guard if there is some risk of damage or leg contact. After its rated 1000 hrs or so, replace it with a spare kept on hand for near 100% uptime. Use more or larger lamps if more wattage is needed. The desirability of this scheme somewhat depends on the desk depth and whether desk side drawers and back panel provide an enclosed space.

Red filtered radiant bulbs for chick heating are also available. These typically operate at a lower color temperature so even more heat than visible light may be produced than with normal tungsten lights, where the infrared output already dominates (90% vs. 10%). Lower color temperature tungsten lights also have a greatly increased lifetime.

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Comments (9)

Elmer J Fudd
6 years ago
The percentage efficiency of a resistance heater is misleading, it's an arbitrary number because they're all the same. All of them.

Electric resistance heaters produce 3400 Btus of heat for 1 kwh (1000 watts used for 1 hour). A 1000 watt heater would produce this heat in one hour and use 1000 watts (1 kwh). A 1200 watt heater would produce 3400 Btus in 50 minutes and also use 1 kwh.

If you want one that's less expensive to operate, get a smaller one so that the heat output isn't more than what's needed. But if having a 500 watt heater on all the time produces enough heat, having a 1000 watt heater on half the time (because of having a thermostat) would produce the same amount of heat and would use the same amount of electricity to do so.
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littlebug zone 5 Missouri
6 years ago
You for sure don’t want something with a fan if you wear contacts or have any eye issues. A little heater blowing under the desk will really dry out your contacts, I found out the hard way.
User
Original Author
6 years ago
last modified: 6 years ago
so as I mentioned above, I absolutely do not want one that blows air.

kaseki -- it's funny you mentioned radiant bulbs, because that's what I was thinking too, haha! I was hoping to find a more elegant, better looking solution. however, if it comes to it, I might go ahead and use a heat bulb. this is meant to be a supplement to make my desk area a small amount warmer.

one side question: our house has a high efficiency heat pump but it's not zoned (it uses central air). I refuse to turn it above 68 when I'm home alone because I just feel so guilty about heating an entire house just to make one room feel warmer. but maybe instead of getting a space heater, it's more efficient to just turn up the thermostat 1-2 degrees? (our house is 1600 SF)
kaseki
6 years ago
last modified: 6 years ago
It will always take less energy to heat a portion of a volume than the entire volume using the same technology, although if the house had zero heat loss, the under-desk heater would eventually end up heating the entire house. But with a heat pump, one is thermodynamically limited by the difference in temperatures between where heat is pulled from and heat is supplied to.

The heat pump's data sheet will provide the effective efficiency, perhaps in the form of a coefficient of performance (COP). If the COP is greater than 1, the usual case in design temperature ranges, the efficiency (watts of heat supplied divided by watts of electrical power used) is over 100%, whereas the direct electrical heating can only be 100%. So there is some temperature difference where your heat pump will more efficiently heat your entire house than an electric heater will heat under your desk, but my guess is that is not going to apply to you very often.

Heat pumps have a limited range of efficient differences in indoor/outdoor temperatures, so at some exterior ambient condition, it is more economically efficient to heat with natural gas, propane, or heating oil.

Heat pumps pulling heat from underground water strata can be efficient even with sub-zero exterior ambient conditions, but initial installation cost may be high.

Bottom line: every circumstance will have its own optimization.
w0lley32
6 years ago
If all you need is a little more heat, I would try just a regular 60 or 100 watt incandescent light bulb. I once had the same problem where my computer room was 2-3 degrees colder than the rest of the house, and a 60 watt bulb in a lamp without the shade was more than enough to keep the room warm, and it gave me plenty of light, too!
Lyndee Lee
6 years ago
Look up under desk heaters. You will see a variety of panel heaters which will have a large even heat, unlike a light bulb. I have had one of those heaters and they are very comfortable with enough output to be cozy but not too much. There are also heated foot rests that might be good, depending on how you sit at your desk.
armoured
6 years ago
You could also look at getting a heating pad for your desk chair, for your back, for example. Most efficient is to only heat the thing that needs to be warmer...
Bruce in Northern Virginia
6 years ago
You might want to try something like this heater. https://www.homedepot.com/p/NewAir-Premium-400-Watt-Electric-Oil-Filled-Smart-Safety-Slim-Portable-Radiant-Space-Heater-for-Personal-Under-Desk-White-AH-400/205588528

The larger portable oil filled heaters provide very even, comfortable heat, so I assume this one would be the same. However, it might be a little larger than you want.

Bruce