I have a challenging space I bought this heater to take care of.  I have a fourseasons sun room over my 8x10 deck.  Other than a lot of sun loading and warmth from my kitchen it does not have a heat source.  It doesn't freeze out there this time of year but it's too cold for comfort. Although better than the tower heater I tried, this heater only gets the room to high 50s or low 60s.  Was hoping to avoid covering the windows but I may need to get some thermal curtains to retain the heat better for at least the winter months.