2 years ago I had a Bryant 2 Ton 13 Seer Air Conditioner + new furnace and coils installed in my 2800 sqft ranch style house with 6 bedrooms and 2 baths split evenly between the basement and main floor. My house was built in 1962 and it has some issues. The AC always has problems keeping up when it's above 90 - 95 degrees out. But, it's gotten worse recently.
2 weeks ago we opened up the basement to the main floor in the living room. Where there used to be a door / hallway and closet, we took all that out and more or less connected the basement main room to the living room in an open floor plan. Thus, there's no closing off the basement anymore. It's always open.
Also, my AC intake is in the upstairs hallway. I have the original ductwork which is 4inch tubes coming off of a 2ft by 1ft high main supply duct. It's all in my floor, none of it is insulated. There are two vents only downstairs, which is more than enough, we usually have them closed off and the downstairs still stays about 65 degrees while the upstairs won't go below 78 on really hot days (95+)
The windows are aluminium single pane. The ceiling has on average, 2 inches of blown-in teddy bear looking insulation. I know my roof has insulation issues because I get ice blocking on the heated part of the house in the winter.
I have a few questions:
Was my AC compressor sized correctly for the house?
Did I completely mess it up by opening up the basement?
Will replacing windows and adding insulation help much?
Finally, what else can I do to make it more efficient?