Making an rv furnace quieter

Myredracer, We use electric heaters anytime we can and I agree they are very quiet. There are times though when we have no 120 to operate them and the gas furnace is used. You have a very good idea and if I can't quiet it down I may do the same as you.

I am pleasantly surprised with how quiet my Adventurer heater and residential AC are. I don't think either one had been used much and the first couple of times we used them they made some noises they don't make now.

The return air for both are part of the bed pedestal and made from soft materials.

The heater cabinet must be lined too but the big thing is the burner makes very little noise, even outside it is quiet.

The majority of the sound from our two furnaces comes from the large cold air returns. I lined the area behind the grills with a sound absorbent material, and even blocked off a section of the over sized grill with the same material, being careful to still exceed the manufacturer's required minimum opening area and minimize restricting air flow. The sound level reductions were significant, although I didn't take any before/after measurements.

myredracer- I like your mod. I’d ask you how it’s done but then there might be a safety kerfuffle on the forum...

Forced air heat is like warming a rock with a hair dryer. It requires noise.

I boondock mostly. I use a Propane catalytic converter (Big Buddy) Not expensive, portable, quiet.

Requires some common sense “supplied by user.”

Don't be surprised when furnace keeps tripping on 'high limit'

Consider a two stage furnace that runs the fan on low when possible.

I came up with a great solution. The furnace is now dead quiet... :)

I installed 3 permanent recessed electric heaters, one in bedroom, one in bathroom and one in kitchen/living area totaling 2KW. Very quiet.
Made my own demand controller that disconnects the heaters while an appliance(s) is running which draw current above a preset level (we are 30 amps). Works like a charm and has to be my favorite mod.

RV furnaces are dang loud. Don't miss it at all! I don't think there's anything that can be done. Need to follow manufacturers spec for clearances, air flow, etc. for safety reasons.