Questions from an ill-informed homeowner:
I've read many posts here & searched around quite a bit, but I couldn't find a good explanation of how zones work.
My guess is that it involves a series of electronically controlled dampers which are programmed to adjust airflow to different areas based on the differing heat losses or gains of each area. I'd imagine that in a sophisticated system like the Carrier Infinity 96, the controller tweaks these dampers to balance flow, pressure, blower speed, etc.
Our house has 2 floors. The upper floor gains & loses more heat [via attic] than the lower floor. I'd guess that this alone is not a sufficient condition to require zoning, as duct sizing could account for most of this differential.
What about cooling just 2 bedrooms at night, and cutting off cooling to the rest of the house?
A related question: in the absence of zoning, wouldn't physically closing off several registers put a strain on the blower motor?
When I asked our possible installer, "Mr. No-J" [who'd never heard of a Manual J] about zoning, he just said we didn't have room for motorized dampers. End of discussion.
Are they that bulky? I suspected that he just didn't know how to design them into our system, or how to program them.
Are these dampers expensive? I know you can't talk about actual costs, but how about as a percentage increase in costs for a new system?
Does anyone care to educate me a little?
Many thanks in advance.