It's just getting cold here at night in Michigan and the water was a nice bath temp in the morning. Hopefully it lasts all winter.

The water was frozen when I put it on top of the ice. It didn't take long to melt, but didn't get hot doing it. Love this thing. I hope it lasts for years.

I had one for about 10 years and it worked wonderfully in my backyard fountain! Ordered another.

This product is by far the best bird bath heater I have ever owned. I tried the flat ceramic type and after a year each, they gave out in the cold Colorado winters. They also collected green scum on them due to bird pooh in the water, even though I cleaned my birdbath every three days. Also the cords were too short, so hard to keep in the bird bath, especially when Crows would peck at the cords, often time would fall out unless weighted down.I have not had that problem with this as the cord is long enough to trail down away from the bird bath and keeps water away from the extension cord I have it plugged into.
So far after going out and cleaning every three days, there has been no green scum on this bird bath heater. It is also heavy enough with a long cord, that it keeps itself weighted in the birdbath.
I love it and I Highly Recommend It over ALL other bird bath heaters.