A. When we show the heat output of the unit, this is based off the temperature of the hot water flowing through the unit used to heat up the tubes of the towel warmer. The unit is recommended to run at a maximum 2000 Btu/hr from the hot water flowing through it. The hotter the water used to heat the tubes of the warmer, the warmer the temperature and higher Btu/hr you will receive from the unit.