You guys are still the most informative site around, so this homeowner says THANKS for being here!
My family has had good fortunes (and good maintenance) keeping our systems running for over 20 years. So now is the time to make plans for what if, and I'm trying to see if I have the correct assumptions. In the first, basement setup we have (2) nat gas furnances (4" and 5") and one water heater (3") exhausting into the same (6") B-vent. This vent is in the center of the house and goes straight up, through the 2nd floor and out of the roof where you see the metal vent/cap. From all appearances it is completely double walled, but only a few feet in the basement is visible.
Since this is in the center of the house, and the basement is finished, it would be highly destructive to try and install any basement level exhaust. So, my assumption is that it would be a good idea to replace these units (I think they are 60k / 80k) with equivalent sized 80% AFUE units? This way I could just reuse the existing vent.
Likewise for the A/C, we are finally forced to convert from R22 to R410. The linesets have been leak free for years, so my assumption is that they could be flushed and reused? Although they do have rusty looking liquid line drirers outside. Totally replacing them would require tearing out 15-20 feet of drywall.
Any comments or thoughts would be appreciated.
1. Replace furnace with a MAX 80% AFUE
2. Reuse linesets when replacing A/C