One thing I do, which may be a bit more difficult/expensive with larger pots, is to double them up - this creates an air space between the outer, heated pot and the actual pot the plant is in which keeps the roots quite cool relatively.
The other thing I do is to wrap the pot in something insulating. On this pot I used an old feed bag, not very aesthetic, but it does the trick and I am sure nicer looking materials can be found
Also, pots made of insulating materials help as well, i.e. wood, ceramic, etc. and the closer to white the pot color is, the cooler the roots.