I'm told I need to replace my central air equipment in a 2200sq ft Connecticut 2 story because of it's age and am also adding 650 Sq ft by converting the over garage attic to a bedroom.
Current equipment: Rheem ROHB-095A heating and Rheem RACC-042JAS cooling. The furnace is cracked and will cost $1800 to fit new parts.
I've had 4 HVAC contractors qoute on replacing the equipment. The general consensus is a Thermo Pride OL11-105 furnace and American Standard Allegiance 14 2A7A4042A1000A (3 1/2 ton) condensor and TXH042C4HPC A coil with 2 zone damper.
Only one contractor did a Manual J calculation or took measurements so I was leaning towards him for his effort. This person also said the J calculation showed my existing ducts could be extended to heat and cool the new attic area. The other contractors said it wouldn't and said I should use a ductless system for the new area and baseboard heating.
Now the kicker. When I asked the Manual J contractor yesterday if he was sure the airflow was sufficient to service the attic bedroom he said (I think) the CFM to the upstairs of the house would be 900CFM and current usage was 700CFM so the system would have to be tweeked by trial and error to make it work correctly and couldn't promise that it ever would.
PLEASE HELP: Where do I go from here? I don't want to just replace my equipment, I want a system that works!!!