Tonight I kept the forced air very low. I used an electric space heater in the front end but the bedroom got down to 50. I was under some layers of blankets and plenty warm.
I purchased a thermometer last weekend that featured an internal temp and humidity with an external transmitter and temp sensor. At 50 degrees and 47% humidity, the dump compartment with the external sensor transmitter had a temperature of 38.1 degrees. Local weather reported the outside temperature at 37 degrees at 8PM and possibility of a freeze tonight.
I brought the cabin heat up to 60-64 degrees with the gas heater and the dump compartment going up to 40-43 degrees. There is still space around the hose that I need to take up with a steel wool barrier for varmints or it might be warmer down there. This weekend I'll install the barrier.
So for ACE owners, yes the compartment heats up. So far about a 21 degree differential. I suppose the rear compartment could get down to 55 degrees without the possibility of freezing pipes. That is if the outside temperature stayed above 25 degrees. BTW, this part of Seattle rarely stays below freezing for more than a few days in the winter.