Efficiency Ratings on Propane Furnaces

[RiverRnr]

I might be looking to install a new furnace for something more efficient, but my searches have not turned up any ratings systems for RV furnaces. The current furnace in my camper works fine, except its exhaust air is hotter and has more volume than what is blown inside the camper. It's an older 18,000 btu Atwood Hydro Flame 7920-II. Are the newer furnaces significantly more efficient? Is there a systems to compare efficiency between new and old units?

Thanks!

[Old-Biscuit]

You have to check EACH models 'Installation Manual' for the published efficiency
Your 7920 ii has a 77% thermal rating
A 'new' model AFSD 18K btu has a 76% thermal rating but is 'quieter'

7900/8000 Series...pg 2 1st paragraph 3rd NOTE:
http://techsupport.pdxrvwholesale.co...ion-Manual.pdf

AFSD Models pg 2 last paragraph 3rd 'bullet'
https://olivertraveltrailers.com/wp-...-AFSD20111.pdf



AF Series is Atwood
DF Series is the SAME but now uses the 'D' for Dometic

Here is the Installation Manual for ALL the New 'D'ometic Series
***But NO mention of 'efficiency' ratings
https://fourwheelcampers.com/wp-cont...FSAD-12111.pdf




Flow out of Exhaust is going to be HOT and have more volume then Room Air thru the Ducts
Exhaust is after the heat generated from combustion is transferred to the Heat Exchanger (less restriction/different combustion wheel)
*Propane flame temp is roughly 3500*F