I bought the Snugglesafe at Petsmart for $40.00 and tried it out in the 3'x4' coop, in the cozy box. It doesn't stay warm for 12 hours. Night temps here are around 30 degrees. Day temps are in the 50's. In my opinion, it's not a good option for the coop. I tried it in the dog bed (in the house), and it didn't stay warm for 12 hours there either. Guess I'll return it this week. Think I'll try containers of boiled water next.