It is important to choose a furnace perfectly suited to the size of your residence. An overly powerful furnace will cycle too much, which will favor poor combustion. Too small a furnace will heat at high level over long periods of time in order to satisfy the thermostat call for heat, which can damage the furnace’s components prematurely. In all cases, a furnace that is poorly adapted to the size of your home will reduce performance. A detailed calculation done by a heating specialist is recommended.