This is the third new home repair I have been called out for in the last two weeks. Same builder and Sub on all three. New homes all 1250-1350 sq ft. All have 2 ton ac units. After the first one, the other two were easy to troubleshoot. All have a around 6-7 x 13-14 dust pattern on the filter. They had a 78-96 sq in return air opening. All homeowner complained of low airflow and unit not coolig properly. All are on gas heat and one did mention high gas bill. I made the hole as large as possible and recharged the units.
I saw this problem for the first time a couple on months ago by the same sub who installed these ac units.
Is there anything else I should look for and what would be the minium size for supply air in this case. I think I'll advise builder of his sub.