I have a customer who can not get below 78 on a 88 degree day. The customer was givin a copy of their Manual J. The company who installed their AC unit (new home-17 months) did not include some items for heat gain. The did not include any heat gain for lighting, people, duct loss and included blinds in all windows. This is a 1800 sq ft ranch with daylight basement. They have a 3 ton unit and the man J
I'm not a man J expert but I think their 3 ton unit is undersized. Their Man J had 32,000 total cooling heat gain.
I don't think I can help them, only give advice of contacting the builder.
Can anyone tell me about how much heat gain was left out?
I'm thinking about 6000-9000 btu????
If I'm correct, they need a 3.5-4 ton unit.