By the way, I have had ours out in -13 and the oil temp is pretty low,
even with the plate on. No battery boost was needed, even with the aging
cable. With thermal underwear it was still too cool for my tastes.

Is that -13 F? If so, I've flown at that temperature, and it's quite
amazing. Everything creaks, and groans, and sounds different.
Pre-flighting is an exercise in endurance, and your eyes water so badly you
can't see a danged thing.

Once everything is warmed up, however, the performance is spectacular!

The heater does not keep the plane at any comfort level below 0F.

Mike, I'd check to make sure the passenger compartment is relatively
airtight. When we flew our Warrior at that temperature (I've not had the
opportunity with the Pathfinder, yet), we were toasty warm in just a few
minutes. That Cherokee heater kicks out a lot of BTUs, and should do the
job, even when it's that cold -- unless the heat is being sucked out through
a bad door seal. (Or under the back seat. Or due to leaky air vents.)

I see what the other respondent was saying about the hangar woes. Here,
they plow in front of the hangars and leave a nice 10-15 inch bump of
snow that turns to solid ice when the sun bounces off the hangars and
partially melts it during the day and it solidifies at night.

Ours, too. We've taken to driving to the airport immediately after a
snowstorm, just so we can clear the area in front of the hangar door. (Our
first year here we didn't know to do that, and there were days when we
literally had to use a hammer and chisel to chip away the ice, just so we
could open the door. It was frozen to the ground!)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"