Hello again, your message got through just fine, I did not get a duplicate. Thank you for the detailed answers to my questions.
CLICK HERE FOR THE RHEEM DATA SHEETS
The lennox furnace number didn't compute.. can you double check it for me please?
This is a tough call... that Rheem furnace is low efficiency, but with an electronically controlled fan motor.. those are expensive and very costly to trouble shoot and replace when they fail. The Lennox systems often use those same type of motors...
I am old fashioned I like simple easy to replace components... I might suffer such complexity with a 90% efficient furnace but I don't like to see it with an 80% efficient furnace where I expect a cheaper, easier to maintain furnace in exchange for the lower efficiency.
$7500 is in the high priced range if the air ducts are already in place.... and the furnace is not in the attic or other difficult to access location.
If you shop around you should be able to get quotes on good equipment in the $5,500 range... made by Rheem, York, and American Standard... and 'Goodman' equipment in the $4500 range. Goodman furnaces are good, and cheap... their condensing units are good, there cooling coils that attach the furnaces have had problems... you might get quotes as low as $4,000 for those installed.
Let me know what you think, we can go from there.
Note: I am traveling in central america now with spotty internet access. I will generally get back to you within an hour or so, but am going to bed shortly.. if you need faster service or can't wait...hit the 'relist' button and your question will go back on the open board for other experts to see.