This AI-generated summary may contain inaccuracies. Please refer to the full thread for complete details.
Members report that RV heat pumps, especially in models like the 2021 3781RL, often struggle to provide strong heat, particularly when outside temperatures drop below 40°F. Several experienced RVers confirm that heat pumps are generally less effective than propane furnaces or electric fireplaces, which offer higher BTU output and faster heating. The consensus is that heat pumps are best for taking the chill off in moderate temperatures but will defer to the furnace as temps approach...
More...
On my 2021 3781RL the heat pump does not push a lot of hot air, and the propane heater kicks on more often than it should.
Is this a low freon condition just like low cool air? what should I look for.
If you have an infrared thermometer, check the output vent temperature near AC compared to the temperature at the return. If you are getting 20+ delta with outside 40-60, the unit is working.
If you determine it is heating, then figuring out where heat loss is happening is next. I found poorly taped vent and returns in mine was allowing air into attic space versus into living space. Collapsed ducts is another thing to check.
My 2014 has a Dometic Brisk Air II HP for the LR.. It will literally run you out of the fifth wheel .. 34 footer...
We camp in W Yellowstone in late Sep thru first week of Oct every year... Nighttime temps are often around 20 degrees... The HP will do fine till about 35 outside temp and the Furnace will kick on when HP can't meet Tstat set point...
** We can easily heat and maintain inside temp at 68 degrees with outside temps at 35 or above just using the HP
Note - the Fan WILL continue to run on the HP unit if HP was selected and then furnace takes over later on but only cold air will blow from overhead vents
I would..
Check the return overhead vent filters on that HP unit.
Check the return ducts for evidence of being partially collapsed inside ( use cell phone camera to look )
Check overhead vents by removing the plastic insert and inspect the tape the factory put on to seal the gap between attic and overhead racetrack ductwork
Your HP on that year Montana should be a Coleman Mach 15 unit... It should do well for heat down to around 35 degrees outside temp..
Additionally— the heat pump never is as hot as the furnace. My wife gets cold when it’s on in the cooler evening as she feels a breeze more than the heat. Doesn’t bother me.
IMHO the heat pump can be useful in moderate temps to take the edge off. When it's pretty cold, but still above 40 degrees, the heat pump can struggle to keep up. It is, at best, a 15k BTU unit. The fireplace is (usually) a 5k BTU unit. The furnaces in our Montys are 35k to 45k BTUs. Ours is 40k BTUs. There's just no comparison to the speed and efficiency of the gas furnace compared to the other devices. I know, these gas furnaces are far from efficient. But they still beat the other units hands down.
Check inside your air returns in the ceiling. Sometimes they are not sealed off from the attic space. Use foil Air Duct tape to seal up any gaps.
If you don't, your unit is pulling cold (winter) hot (summer) air from the attic. Also trim back and excess on the return opening. Better airflow
Check inside your air returns in the ceiling. Sometimes they are not sealed off from the attic space. Use foil Air Duct tape to seal up any gaps.
If you don't, your unit is pulling cold (winter) hot (summer) air from the attic. Also trim back and excess on the return opening. Better airflow
