UTtrailrider just told us in chat about a waterer that never freezes - go to www.horsedrinker.com. Looks like a good product.

I love the ones that go thru the plug hole on the rubbermade troughs and sit on the bottom of the tank. Mine have lasted 4/5 yrs now with no issues. Not only are they out of the horses reach but you can hide the cord pretty easy too. The only part I don't like about them is it can be kind of tricky to get it lined up right so it doesn't leak thru the plug hole and that can be a real pain when it's freezing cold and your hands are wet. Best lessons learned (and re- learned lol) are to get them in BEFORE the freezing weather.

Outside of the under bowl heaters for automatic waters that work great I have used the floating heaters with little success being they are to dangerous in my opinion being horses can play with them. I found the through wall heaters work great and yes I have used extension cords for them. Like any electrical appliance sizing extension cords is most important. Especially when there is a large load on the cord. So remember to size up and the longer the distance for the run the larger the cord as well. Just like running Romex underground either to a junction box or auto waterer size is important. Myself I have my runs about 75 to 100 feet from the panel and use underground Romex 10/2 for the auto waterers.. Check with your electrical supply house for your specific needs It is very easy to drill the appropriate diameter hole for the in wall heaters to adapt to metal tanks or poly tanks.

Well heck yes. (ha) Been using this one for 2 yrs and got it at TSC for $15. + change. The one it replaced had lasted 7 yrs. and got it at Geebos for a bit less I think. Both are the floating kind and I put a cage around them, so they don't get messed with. This yr the ext cord only has to run about 20 ft but was twice that far in the past. Just make sure it's an "outdoor use", heavy cord. Spent more on elec cord than the heater. lol I wouldn't spend my money on the plug inserted or bottom rest type. I know lots of folks love 'em...I'm just not one of them. (ha) Good Luck... D'na

Has anyone had any luck with a stock tank heater that actually lasts more than a few weeks? Also one that says you can use it with an extension cord.