We just got our first corn snake last week He is housed in a 10 gallon aquarium now, but later this week I am getting him a 20 gallon long Critter Keeper. My question is what size UTH to get to heat the larger tank. Should a UTH cover half the underside of the tank ? I am in Pa. so it is cold here now. My house is kept rather cool 66-68 degrees because my son has asthma and if it's to warm he weezes. I would like advice on what size, wattage, brand and maybe where you got yours to make this transition to the larger tank. I am unsure weather to go with a UTH that has a thermostat or buy a dimmer at lowes. Any suggestions would be greatly appreciated. Thanks