1696SF 2 story over unfinished basement. 14 windows. Built 1985 with 2/4 walls, fiber wall blankets, blown in attic, masonite over polystyrene. GOOD CENTS house with storm windows. Insulated ground floor joists. Located northwest mero Atlanta. Faces north - northwest.
I have 3 ton 12SEER RUUD with matching gas single with fixed speed air handler. July, August does great but other times doesn't run enough to pull humidity down. AH is set at lowest speed to get best hu reduction and that helped alot over original setting. One year when it rained alot I got sweating registers so maybe I've slowed down too much.
Jumped from an original 2 TON 8SEER HP that wasn't getting it done. Thought maybe I oversized too much and was looking at a 2 1/2 ton unit. AH is rated for 2 1/2T to 3T.
After reading this board looks like VS AH might also be a choice with existing 3T.
The short form requires extensive measured inputs and produced results that were consistent with the two originally installed Carrier units. The short form predicted that I would need a 1/2 ton more on the side of the house that had been expanded (with a lot of glass).
BTW, I invited four different local (Phoenix, Az.) dealers to quote replacements and not one of them did a load calc.
I ended up with a 14 SEER/12 EER Rheem (Ruud) 3 ton gas pack and a 2.5ton split system. So far, I am pleased to say that the new units are consuming about 1/3 of the peak KWH of the old ones (installed 1975). The scroll compressors are incredibly quieter.
Thanks much JCHunter. This is what I've been looking for.
Like you I could not get a heat loss calc. Talked to 3 or 4 guys and answer was always " I've been doing this for X years and I know what I'm doing". Wish I'd found this site or held out for someone more technical.