I will be starting construction on a new house in a few months in the north Dallas area, and I've decided to get a Carrier Infinity HP/furnace system with zoning. (Sorry, I've consumed the Carrier Kool-Aid along with my brother who has one of these wonderful systems. )
My house will be just over 5,000 sq ft (4,000 on first floor and 1,000 on second floor). I'm having the house built wiith spray-foam insulation (attic will be in semi-conditioned space), and have already had a Manual J done by somebody who specializes in spray foam / SIP / ICF / etc, so I trust his work.
The Manual J calls for a single 5-ton AC/HP, with 60 kBTUH of heating.
I'd like to get EIGHT (8) zones installed. Yes, I know that's probably insane, but it's waht I want.
The maximum cooling CFM for the largest zone to the smallest zone is about 2.4 to 1. I have five zones between 160 CFM and 210 CFM, and three zones between 300 CFM and 390 CFM.
Right now I'm considering the 255HNA9 (scroll compressor) or the 25HNA6 (recip compressor) as the heat pump. I prefer most things about the scroll compressor, except the recip compressor seems better suited for keeping the humidity levels under control during the spring and fall. I'm REALLY interested in getting the new variable speed compressor heat pump by Carrier that's supposed to be out this summer (hopefully in time for my new house).
See http://www.achrnews.com/Articles/Fea...00000001016449 for a link to this new heat pump.
I'm a bit leary of going with HP only for heat (since I've never had one before), so I'm considernig the Infinity ICS furnace (80 kBTUH in size) for its alleged quietness and also the 3-stage burner. Having a heat pump will be like adding a 4th stage. Seems like it'll be VERY comfortable in winter.
All that just to let you know what I'm planning. And now to the question.
Where's a good place that I can get the duct work properly done for such an atypical install (8 relatively small zones) ? Preferably in the Dallas area, but that's not a requirement. Ductwork is just as important in ai good HVAC system, and this is so atypical I want somebody who really knows what he's doing when it gets designed. It doesn't necessarily have to be the person who does the install, either. I'm perfectly willing to pay for a duct design, just like I paid separately for my manual J calculation.
I've studied as much as I can on designing the system with links like these:
and also the Product Data sheets like these"
that I think I know the basics of what has to be done. In a nutshell, every zone must be designed to the minimum airflow requirement for the system. However, all the different documents seem to sometimes contradict each other (sometimes even within the same document). So, I can come up with as low as 900 CFM for each duct to as zone as 1400 CFM for each zone. That's probably a different thread to get an answer to that, though. But hopefully somebody who's done these before will be best qualifed to give me the right answer.
I'm looking forward to getting some recommendations on anybody who can help me design this right. I do have one option already . . a guy in Nashville associated with the firm (here in north Dallas) who did my Manual J. He knows how to properfly design systems, I'm quite sure, but I doubt he's that familair with the Infinity Zoning system (especiallly with so many zones).