Speedheat RugBuddy 365 Under Rug Electric Space Heater - 6'9" x 4'10" - Safe & Energy Efficient Floor Heating for Home & Office - Perfect for Living Rooms, Bedrooms & Cold Floors

I got it and first used it on a 55 degree day in a summer cottage with a cement floor and no heat. I plugged it in and waited about 20 minutes. I took off my shoes and stood on it. It didn't exactly feel toasty warm so I wasn't sure if it was working but when I pointed my laser thermometer at it, it read 72F so it was definitely working. The cement floor read 58F in the rest of the cottage. After 3 hours of use I didnt notice that it warmed the air in the room but it made me feel warmer sitting or standing on it. It's effect is definitely subtle. I used a very thin soft Oriental carpet over it. I'm happy with my purchase but a space heater will still be necessary to really heat the air in the room. I use it with a thermostat built into power plug adapter so the rug heat comes on when temp in the room dips below 65 so that's nice. I recommend this approach as it saves me from unnecessary power consumption.