We purchased this 120v Stainless Steel Waterproof Heater to help extend the growing season in our 12' x 32' greenhouse in Tennessee and are very happy with it's performance. So far in mid-December in zone 6, it has helped keep our greenhouse 10+ degrees above the outside temperature, which is enough for our tomatoes, peppers, cucumbers, lettuce, herbs, lemon trees, avocado trees, and flowers to keep growing. We did purchase the plug in thermostat to help us regulate the temperature, turning the heater on and off as needed. We are very pleased with both purchases.

I have a very basic hoop house with no insulation. I purchased this heater to keep the temperature in the house between 35 - 40 degrees F on nights the outside temperature is below freezing. This heater did a great job doing that - and my electric bill was not too high.

 

I have been very pleased with this little heater! We had 3 nights in a row where it got down to 15-18 degrees and I was so worried, but the heater kept pumping out the heat and kept my little greenhouse at about 45.

I got this for my little cedar greenhouse (about 100 sq ft area) in southern Alabama this winter. It kept the temperature above freezing during our coldest nights when the outdoor temps were as low as 19 degrees. I'm running the heater now because I started my veggies seeds this month and it's doing a great job. I like the design and safety features. I may get another one for my pump house.

This little heater seems to be working great and keeping my 10' X 12' greenhouse at 50-degrees F. Coldest we've had here so far is 32-degrees F.