We had a Carrier 58MVC 3 stage furnace installed last winter. At the time we had several bids; all were for a 100k btu unit except for this one, which spec'd 80k btu.
This was to replace an older 100k unit in a 2800 sq ft house in Portland, OR. I was actually skeptical about all of the bids, considering no one was willing to do a calc. But the company guaranteed our satisfaction so we went with their assessment - 80k btu.
Basically, the unit is great in conjunction with the programmable thermostat- normally in the lowest stage. However, the problem is when we want "heat on demand" - when someone gets up earlier than expected, or we come home earlier than expected, it just seems to take much longer than the old furnace to come up a couple of degrees. The heat and velocity coming from the registers is just not very satisfying.
Before getting into the technical issues, I just wanted to ask what kind of performance one should expect in terms of bring a room up to 68 degrees, from say 62 degrees when the weather is 35 degrees outside.
For some context - 2 stories (over a small basement) 2800 square foot house, built in 1988. 2 x 6 construction, average tightness but lots of windows. In Portland with relatively mild winters.