Can’t cool living space: AC ducts in unconditioned attic
I’m looking for some advice for a solution to a problem I have struggled with for awhile now.
I live in a 2 story home and our main living area in on the top floor of the house. Our garage and fully finished daylight basement is on the lower level. On our main level (2nd story), the house has always been difficult to cool below 76 degrees during a hot summer afternoon and often will not cool down to our desired 72 degrees until 10pm or so at night after the attic has cooled off. We just had a new evaporator put in our AC unit which is the largest residential unit available. We have 12 foot ceilings, and several can non IC rated can lights (which I know is an issue). Our attic has varying levels of insulation and the weak spots are under the attic floorboard which has been nailed down making it difficult to remove. I was able to remove some areas and discovered R-19. Living in AL, I realize this is not enough. However, other areas are a good R30 or so. I have 2 PAV’s which run constantly with my AC ALL day which I keep on 75 degrees during the day. The HVAC is in the attic so moving it is not an option, however, should I disconnect my PAV’s, seal the areas I can access and add more blown insulation or should I spray foam the rafters? Ironically the prices i’ve been quoted are close and the spray foam option was only $2k more for a conditioned attic. The companies that quoted sealing my top plates, etc would not remove the floorboards, so I’m thinking that would be a waste of money since there is very little insulation under those. Another option I thought of would be to lay batts of insulation over the attic floor in addition to adding more blown in the uncovered areas. Would that help? I’m cautous over spray foam as I’ve heard about the health hazards and installation nightmares that leave “fishy” odors in the house….any advice appreciated!