Well, looks like its about time to replace my old furnace and finally install A/C into his old home as well. Considering a couple of units and solutions currently. Did a load calc on the house using our standard sheets from work and came up with 30610BTU heat gain, and then went ahead and double checked using http://www.loadcalc.net/load.php just out of curiousity on how close it would be. Few extra options there with shading and vinyl windows, came out to 30475 cooling load, 29675 sensible and 800btu latent load. Pretty close. Design temps used were 97* outside, 75* inside. Looking at installing a Lennox SL280 and likely go with the XC17 outside unit, I'm coming up with AHRI ratings of 28600btu capacity using a 2.5ton unit. I also have a few large fish tanks in the home, so I'm not sure how that is going to affect the cooling and humidity removal capacity of the machine on those hot days.
Is the 2.5ton going to cut it? Or should I step up to a 3ton? Maybe take a look at the XC16 and go with two stage cooling?
The house design itself leaves not a lot of room to work with ductwork as its inaccessible without tearing the hall ceiling out - a modified Eichler-esque home. No crawl space and no attic. Also curious on where might be the best place to mount the condenser, I could place it on the side of the home in the shade and run a lineset over the roof or should I consider placing it on the foam roof?