For you guys already flying what are you doing about supplying air to your heater core; cockpit air or dedicated outside air source?

Typically, with a reasonable amount of flow, you’ll get 30-50 heat-up of the air through the heater core.  So running outside air through from a scoop works OK until you REALLY need it – when the outside air is somewhere below freezing.  Because of that I chose to recirculate the cabin air.  The most efficient blowers are centrifugal (squirrel-cage) so they give you the most blow for the least weight and power.

For those flying with recirc. air do you ever have windscreen fogging like you do in a car on humid days in the recirc. Position

Unfortunately (or fortunately) I haven’t flown in enough cold weather to find out.

Al G