“I actually use this for a very unusual purpose. I raise bonsai, and have to winter some of them in a small vinyl greenhouse. The greenhouse naturally maintains a temperature only about 4 degrees above the outside temp. So far we’ve had a very cold season, and it is only January!
Finding a safe, inexpensive way to keep the temp in the greenhouse above freezing, has been a challenge. It’s a very humid environment, so electronics have to be sealed. Gas or propane is not good either. I found this, and to put it around a sealed 5 gallon pail of water. The heated bucket consistently puts off enough heat that I think my trees my survive the winter. It’s not a perfect solution, but it’s the best I’ve found short of building a serious greenhouse.”