If there is more than a 5 degree split between interior temp and desired set temp, the furnace will come on to assist in heating the unit. The heat pump is more of a “maintain” the temp and not so much a “heat the trailer” when temps fall.
2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.