My A\C and Heater have problems keeping up in Hot\cold weather. Its summer now (I live in the Stl area) and when its 90+ sunny my house will not get colder than 80 degrees A\C going non stop. The A\C is putting out anywhere from 59-62 degrees and from what I can tell is sized properly. In my ceiling is blown in insulation at about 4-5" sitting just above the 2x4s some places more some less. The vaulted ceiling being a little more at around 6" Is this enough? Is my problem the Heating\Cooling unit or is there not enough insulation?
The minimum ceiling insulation should be R-30, with R-40 being the norm in the northern part of the U.S. The depth of insulation required to produce a R-30 depends on the type of insulation. Blown-in fiberglass will have about R-2.25 per inch, blown-in cellulose has about R-3.5 per inch and fiberglass batt has about R-3 per inch. In case you're not sure what type you have, fiberglass insulation looks like cotton candy, while cellulose looks likes ground-up newspaper. Batts are the best to install as there will be less airborne particles to breath, get in your eyes, etc. You just cut them to size and lay them across the ceiling joist so they seal any gaps caused by the ceiling joist, fans, light fixtures, etc.