Background: valve is shot on an old gas furnace/AC system, mixed components (24 years old). Oversized, 9-SEER.
Goals: 1) Reduce Noise (ductless return air at base of unit). 2) Cost: our condo is for sale (but may not sell for awhile).
The last contractor I talked with is steering me away from a modulating furnace, and towards a 2-stage furnace, 2-stage AC, slight reduction in size from 5 tons to 4 tons (Carrier or York). Last winter I obtained a proposal for a Coleman modulating 80% furnace with a single stage AC. I hadn't considered the implications of the single stage AC until now.
Our unit covers three floors, ground level is mostly a garage. The recent contractor said 2-stage systems work well in split level units.
1) Is his advice sound? What are the benefits of a modulating furnace in terms of noise reduction, if any? Is this only a matter of comfort or would the modulating furnace reduce noise? (Essentially, I would be swapping a 2-stage AC for the Modulating furnace--but still paying more.)
2) Would a single stage AC be either on or off, or would the fan/blower still be variable?
3) Is there that big a difference between that quality of brands such as Coleman or York/Carrier that I should be concerned with it--and willing to pay more?