I have one of those commercial heaters that Tractor Supply sells for heating waterers. I've always put it inside the coop but would like to use it outside instead, It may be exposed to rain or snow at times and -15 wind chills. Possible? Thanks!
Commercial water heater
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I would be concerned if the unit is sitting in water (you know water and electricity don't mix well), but as long as you put it on a platform that is raised and drains well, I think it should be fine. If you are afraid of possible problems, use a GFCI somewhere in the circuit, though if it trips, your water will freeze, potentially damaging the heater.
It's hard to be more specific without a picture of the model you are referring to.
This is the model I have. If I put it up on cement block it should be OK I think.
That should work, I would be concerned about water reaching the electrical connections under the pan, so it would probably be best to put it on a board or several cinder blocks that don't leave any exposed areas on the underside.
It seems like this is a pretty inefficient way of heating a water bowl. I use bowls like this: http://www.tractorsupply.com/tsc/product/farm-innovators-round-heated-pet-bowl-6-qt
This is only 60 watt and I think it will do a much better job than a 60w bulb in the metal pan type heater you have. Of course it's cheaper to use what you already have. Maybe this would be a good Christmas gift !