I have two of these for winter usage -
heater - one in the garage, one in the main living area. Keeps it very comfortable on low/med settings. Generally have the thermostat set at ~68-70 degrees on the heaters. I have the RV furnace set at 64. While on a 3 week trip where the avg nightly temp was in the low to mid 40's, the furnace would run a few times from midnight-ish though dawn.
That said, mine is a 4113, so somewhat different floorplan, but performance should be similar.