I'm building a new house with my wife. I am looking at the carrier infinity zoning system and am looking for clarification on how the system actually operates.

I plan on having 7 zones (one for each of the 4 bedrooms upstairs, one for the main floor and two zones in the basement). Some zones will be quite small but I understand this shouldn't be a problem with the infinity system.

What I am wondering is if the infinity 98 system will modulate up and down even when one zone is calling in an attempt to achieve the longest possible runtimes (e.g., if one small zone is calling, it will start at its lowest available fire rate which I believe is 40%, and modulate up and down based on the load-tracking of that zone... or if other zones call it will increase fire rate and so on).

I currently have the Lennox SLP98V in my home, and I understand that the harmony iii board does not modulate the furnace at all - it will only start the furnace at a static fire rate based the percentage jumpers into the board. NO modulating capability.

I know the infinity 98 will modulate up and down in a single zone application (as will the slp98v) - but how about in zoning applications as I described above?

... and any HVAC guys want to tackle my project in Toronto?

Many thanks