Furnaces. Very inefficient!
Seems to me that the furnaces in rv's are patheticly inefficient. There are natural gas house furnaces that are so good that the exhausts are plastic!
Forum Discussion
It's not just the efficiency of the furnace itself that's an issue.
Many RVs nowadays have an enclosed underbelly and the furnace pumps some of the furnace output into the underbelly cavity to prevent the tanks and piping from freezing and to make the floor feel warmer. As a result, some of the heat ends up going into the great outdoors through cracks and gaps instead of being recirculated. Very inefficient design.
Secondly, the ducting is partly to blame. The flexible duct (2" & 4") they use creates friction loss. Sometimes they stuff lots of unnecessary extra duct in the runs rather than trim it and to keep bends to a minimum. As well, if a duct goes into the underbelly space and comes back up into a heated area, the duct won't be insulated and it may be sitting on top of the coroplast with no insulation.
Thirdly, the way they install the duct in some locations can cause it to become partially collapsed and thus restricting air flow.
Lastly, you may have large openings whacked into the floor for ducting & pipes. Ours had a large opening right next to the furnace and some return air was being drawn into the furnace from cold outdoor air.
Our furnace struggled to keep our TT sufficiently warm in temps around 40F and below and took forever to warm the interior up. Dealer claimed it was a faulty sail switch, but that was not the case at all. Our trailer has a 4" duct that goes into the underbelly space and back up to an outlet in the kitchen. I pulled it out and insulated it and used semi-rigid aluminum duct. I also increased the duct to the bedroom from 2" to 4". HUGE, HUGE improvement! Full story and pics here on another thread from a few days back. under-performing furnace
Last year I installed 3 permanent recessed electric heaters totally 1750 watts along with a demand controller I built that shuts the heat off when an high demand appliance gets plugged so our 30 amp breaker won't trip. Didn't have to use our furnace once last season. There may be times though that we could end up dry camping and still need the furnace.
Many RVs nowadays have an enclosed underbelly and the furnace pumps some of the furnace output into the underbelly cavity to prevent the tanks and piping from freezing and to make the floor feel warmer. As a result, some of the heat ends up going into the great outdoors through cracks and gaps instead of being recirculated. Very inefficient design.
Secondly, the ducting is partly to blame. The flexible duct (2" & 4") they use creates friction loss. Sometimes they stuff lots of unnecessary extra duct in the runs rather than trim it and to keep bends to a minimum. As well, if a duct goes into the underbelly space and comes back up into a heated area, the duct won't be insulated and it may be sitting on top of the coroplast with no insulation.
Thirdly, the way they install the duct in some locations can cause it to become partially collapsed and thus restricting air flow.
Lastly, you may have large openings whacked into the floor for ducting & pipes. Ours had a large opening right next to the furnace and some return air was being drawn into the furnace from cold outdoor air.
Our furnace struggled to keep our TT sufficiently warm in temps around 40F and below and took forever to warm the interior up. Dealer claimed it was a faulty sail switch, but that was not the case at all. Our trailer has a 4" duct that goes into the underbelly space and back up to an outlet in the kitchen. I pulled it out and insulated it and used semi-rigid aluminum duct. I also increased the duct to the bedroom from 2" to 4". HUGE, HUGE improvement! Full story and pics here on another thread from a few days back. under-performing furnace
Last year I installed 3 permanent recessed electric heaters totally 1750 watts along with a demand controller I built that shuts the heat off when an high demand appliance gets plugged so our 30 amp breaker won't trip. Didn't have to use our furnace once last season. There may be times though that we could end up dry camping and still need the furnace.
