I should have mentioned my grey did not use the perch the first winter. I put it away thinking it was a waste of money. He is typically suspicious of all new things, as are most greys I guess. Although I ended up happy with this purchase, I'll admit I've been "a sucker" plenty of times.
My grey likes the thermo perch. I live in a colder climate and am happy to know if he is a little chilled he can sit on it. Also I understand parrots feet are the first way for us to know when they are chilled. I 've noticed this to be true with my bird. The perch keeps a steady temperature and takes electricity the same as a light bulb.