If you are using inaccurate thermometers, this might be giving you the impression that your tank is too cold. Make sure you have digital thermometers and at least one with a wired probe to measure the exact temperature of your UTH.

If you house temperature is around or above 75*, you shouldn't need anything other then a UTH regulated by a reptile thermostat (this is important to prevent burns to your snake).

If your house is on the cool side, you will need some kind of supplemental heat since UTH's don't heat the air around them, just the surface they are adhered to. Some people do this with red bulbs, moonlight bulbs, ceramic heat emitters, or another UTH if their house isn't frigid. The thing with lamps is they do make it very hard to keep your humidity up. If you can avoid lamps altogether, that is ideal.