What size is your OEM furnace? If it's the '16000 Btu' NT16SE Suburban that's a non-ducted type, I feel your pain. They're common in many class B's and small C's like my Tiger, and their main function seems to be turning battery amps into noise. If you've got one of these, remove the two exposed screws and the front cover. You'll find a label that states the actual
output as
12,160 Btu. 'Nother words, it's about 75% efficient.
I'm pretty close to replacing the NT16SE in my '06 Tiger CX with a Propex HS2800, just to get rid of most of the noise.
http://www.rockymountainwesty.com/Propex_HS2800_Heating_Unit_p/hs2800.htm. It'll probably be nearly a wash on amps consumed due to longer run times at lower output. But I don't expect to be blasted out of a sound sleep by a jet afterburner after making the change.
Just trying to decide whether to make a 360 mile round-trip to hear one run, or go with my gut & order one now.
Jim, "Mo' coffee!"