Hi reed,
Replace the return air grill on the furnace with a fan. On my rv that circulates warm "living space" air under the cabinets and pushes some air along the furnace duct work. I chose to use a dual window fan unit which is controlled by a mechanical thermostat that lives beside the water pump next to the outside wall of the RV.
The fan unit draws just 23 watts and works better than a 1500 watt fan based heater which I tried using inside the cabinet.
reed cundiff wrote:
We do use am Olympian Wave 8 which puts out 8000 BTU or 2.5 kW. Works great but at temperatures below zero, the sewer outlets freeze. It got down to minus 5 F just before we flew down to Guatemala for 9 to 11 weeks, and this is where we are now.
The Olympian Wave 8 is sufficient to keep the 34 5th wheel in the 60s at sub freezing temperatures.