I bought my first wall heater about a year and a half ago, maybe two years, and installed the unit in my guest bedroom. Suffice it to say, it works great! Now, I recently purchased another one with the smart wifi. Love that one, as well. Currently running the 24 to 48 hour breakin period at high temp. I installed this one in my living room and it is doing a great job of heating. This room is about 170 square feet. I live in Orange County, California, along the coast. Temps are moderate compared to other areas. The two units I have installed are 500 watts/ 120volts.