Advice please to upgrade my heating system. My 12 years old house in BC Canada has 2 levels: Main level 1400 sf and ground level 1000 sf. Currently using 12 years old Luxaire Furnace model# PACE-L12N080A 80% efficiency 80,000 BTU input. It's quite noisy when running.
I talked to several Contractors who gave me quotes mainly based on the square feet of the house and the size of the old furnace. One recommended Trane 2 stage 95% 80,000 BTU while other quoted Carrier 96.6% 2 stages 60,000 BTU
I found out lately from this site that my duct system might not be good even for the current furnace's capacity. Here is the details:
It is the extended plenum configuration where, there are two 4" round ducts, one 5" round duct coming off the plenum. The 20 feet extended plenum with the size of 8"x14" also comes off the plenum. There are about 10 5" ducts coming off from the top of the extended plenum along its 20 feet length.
Would you please recommend what is the max CFM that my duct system can handle? Based on that max CFM, what is the best size of the furnace for this duct system? Upgrading the duct system is not a good solution at the moment.