Quote:
Originally Posted by Dave W
A ponderable - why is an RVs a/c air (kinda) filtered and the furnace air not  ? Hmmm |
I suspect the reason is the fins on the A/C units are very close together and will clog up very easy if the return air is not filtered, but the heaters develop very high heat and will burn off any lint or dust that gets into the air system of the heater. The following is from the Atwood heater manual, and listed as one of the "The 4 Always".
#4 - RETURN AIR
The return air passage should meet the minimum square
inches as specified for the particular model of furnace in the
installation instructions. This air passage should also be
clean and clear of obstructions. Do not put air filters in this
passage way. Also make sure that combustibles are not
stored in the furnace compartment.