A load calculation is best IF you don't fudge input numbers to get the answer you want. Newer homes in our area can be as little as 1,000 sqft per ton, 800sq ft per ton is common. Older homes and upstairs units can go as high as 350sq ft per ton. Unfortunately "rule of thumb" 500sq ft per ton is what typically gets installed regardless of actual load...
On the heat side pick the smallest capacity furnace that has the blower size you need for A/C, it's more than enough heat for just about any southern home.
My 2000 sq ft house has a cooling load of 1.5 tons - you are not going to get a return call if you ROT a 3.5 to 4 ton price at me. Just sayin.....
I get the whole "quote over the phone" thing for people who are just price shopping but on a sales call - a quick load calc is not that hard to do. You can adjust from there if you get the job. My experience is there are quite a few contractors out there that will ballpark something and install inappropriate size equipment. The way homes and equipment are being built today, it is harder to just make a guess at what you need. As an aside, we do have the luxury in Indiana of not having a statewide heating and cooling contractor licensing requirement. What fun when you get into rural areas.
The other thing we should be doing as contractors is evaluating the structure and making recommendations on energy efficiency improvements so we can make the equipment smaller. Better for everyone.
Most will figure 500 sq ft per ton, but also U will need to consider lots of factors. Cause I have been many homes with lots of windows and very high ceilings and that figure want work. Also some units that are too tight with today's technology of foam insulation will cause problems for size of units. Just my thought on the subject. Good luck
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Originally Posted by zxcb
