A vehicle heat transfer module including a conduit for air circulation, an
evaporator in the conduit between the cabin air input and cabin air
output, and a heater having vehicle engine coolant circulated
therethrough, the heater being in a first path between the evaporator and
the cabin air output. A first door selectively opens or closes the fresh
air input and fresh air output, and a second door blocks a selected
amount of cabin air from the first path. A controller controls the first
and second doors responsive to heating and cooling requirements. Cabin
and fresh air is selectively circulated over the heater and evaporator
responsive to detected requirements, including selectively either (a)
circulating cabin air from the cabin air input over the evaporator and
out the cabin air output, and circulating fresh air from the fresh air
input over the heater and out the fresh air output, or (b) blocking the
fresh air input and fresh air output and passing cabin air from the cabin
air input over one or both of the evaporator and the heater and out the
cabin air output.