I know that our propane furnace heat on our 2000 U270 is ducted to the bays. I'm assuming that the heat pumps on our air conditioners are not. Please confirm. Thanks.
Correct, the roof mounted A/C heat pumps are not ducted to storage or wet bay.
If a coach has two propane furnaces, normally only the rear furnace supplies heat to the wet bay.
My 36' 98 U270 uses propane furnace for bays. This winter when my furnace quit working the heat passively entered the bays from the main cabin while using heat strips and ceramic heaters. Also had two 200 watt heaters that came on in the bays at 37 degrees. There was a 20 to 25 degree differential.
Roof air's do not have an air flow into bay.
Some think that roof air's with heat pump are not a practical purchase.
Only roof air's can cool and several things can heat, so why not extend roof air longevity by only running the unit to cool.
Heat Pumps have a special additional reversing valve (Reversing valve - Wikipedia (http://bit.ly/3uj8OD7)) that can be a problematic weak-link.
Without heat pump, all coolant lines are sealed and often last for more than 20 years without any leaks.
With heat pump, high pressure lines are not sealed from end to end and have a valve that switches pressure flows.
I have never tried my heat pump and I never will. I much rather run heaters on the floor as heat rises.
We've enjoyed our new Dometics heat pumps. Above 40degrees they warm the coach nicely and save propane. Our original Dometics lasted 20 years...I only hope that we last 20 years to wear the new ones out. And the 15k units do an even better job cooling. With the soft starts we can run one of them on AC for 6 hours if needed.
Randy, when our aqua hot had issues when we first arrived here in Yellowstone, we were faced with temps all over the place. When we had temps over 30, we ran our heat pumps with zero issues. They warmed the coach even at temps below 35 degrees. We ran the aqua hot on electric for the bays and it did well enough that we had no issues! Happy we had the heat pumps!
I was very surprised that the heat pumps had found enough warm air at those temps!