Where to get Carrier Infinity Zone design done?
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).
You should be able to get your local Carrier dealer to do the design.
Remember, Air Conditioning begins with AIR.
That would be ideal, I suppose. But the trick is finding a dealer that actually knows what he's doing when it comes to this kinda stuff.
I was (thankfully) sent to the load-calculation specialist by the HVAC guy my builder typically uses, because he admitted he doesn't know how to size properly for houses insulated with foam spray on the rafters and walls. Score one for honesty.
Another HVAC guy I talked to didn't even think you could do 8 zones with the Infinity system (thought it was only 4), and also thought I should put in about twice as much as recommended by the Manual-J, saying that it'd be cheaper to run both systems in low stage all the time anyway. I think he's missing the point of a dual-stage system.
Anyway, it seems simpler to actually find a 3rd party who'd design the ducting, and then get bids from several contractors to provide the actual installation of the units specified by me as designed by the 3rd party heat load and duct design people. At least that way, I get "apples to apples" bids.
There are many factors to consider when selecting someone to install a zoned infinity system.
1. Dealer recognition: Carrier has Presidents Award Dealers and Distinguished Dealers but that is only a small part. Check Carriers web site http://www.residential.carrier.com/dealers/index.shtml as a start for dealers in your area.
2. Dealer reputation: Far more important than awards, after you call dealers in your area call some of their customers who have actually had zoning systems installed for a few years to see how well the dealer responded to follow up balancing issues.
3. Manual-J can be done simplistically and also very well. It all depends on the skill and time the dealer spends.The better Carrier dealers have access the a Carrier version of the a great HVAC software suite which can take into account ALL aspects a system design specifically Manual-J and Duct design. AND simulate the effects of different cooling loads, equipment configurations etc.
The point is that the best dealer for you will have a great reputation and the right tools.
Call around and ask about how many installations they have done with Infinity zoning. Ask what software they use and how long it takes them to accomplish a full survey of your plans. The better the quality of energy audit the more you will be happy in the long run.
The bottom line is that duct design is only one part of a successful installation and should not be a major focus. Find the right Pro first then discuss duct design.
Try Contacting LWarren http://hvac-talk.com/vbb/member.php?u=5682 a member here, his contact info is listed in his profile.
He is a controls guru working for a very reputable mechanical contractor in your area.
I am uncertain "if" they do any residential work or not, but its worth asking him.
I would also suggest entering your zip code into the "find a dealer" link on Carrier's website. I do know the list is not in any order, a different dealer will be on top each time you do a search. But all the dealers are shown with their certifications and awards listed.
But I would also tell you this: I think it's too many zones for a typical carrier system. The controls are set up to do 4 zones each, and more than one may be connected, but you are going to run into limits based on too small of a zone. I would either rethink the type of system to use or try to cut back on the zones. With an Infinity, you are going to be having zones open up that are not calling just to have this work. So that may defeat even having such small zones. There are systems that use one condenser to feed several very small air handlers. (Dankin?) (Mitsubishi?) Sort of like having many mini-splits but without the wall mounted units. The Infinity is amazing, but I would let an expert design it, not start with you insisting on too many zones for it to work right.
You need to wait for the carrier variable speed heat pump 25VNA to come out. It has a capacity reduction rate of 60% and 13 HSPF. That is what I recommend because of the amount of zones you are using. It will be out 2nd quarter of this year.
I thought I mentioned that in the first post.
Originally Posted by jasonairmaster
When do you think I can get a Product Data sheet for it?
Edit: Never mind, I found it:
I need to get on a list somewhere so I can get it. I just hope it's not sky-high in price.
Oh the price is going to be up there...
Just letting you know our carrier rep advises us not to go more than 4 zones on the the 25hna9. They would allow us to do it on the 25hna6 but that unit is no longer made.The 25vna will be the match for eight zones plus warmer temps coming out of your ducts. But you seem youre in a perfect climate for a hybrid heat system.
I just noticed that this thing (in a 5-ton) can put out 52,500 BTUH at 17F. Wowza! That's about 10% low to my manual-J calculations, but I suspect that zoning would allow for that much leeway.
Originally Posted by jasonairmaster
So, if the increased cost is on a par with the cost of the 58MVC (ICS) Furnace, then it's absolutely worth considering.
Is it really the number of zones that matters, or the CFM requirements per zone?
Just letting you know our carrier rep advises us not to go more than 4 zones on the the 25hna9. They would allow us to do it on the 25hna6 but that unit is no longer made.
Is there any problem (other than cost and size) with overdesigning the ductwork to handle the minimum CFM? Say the minimum CFM is 1200 vs. 150 required for the zone. Is that a problem? Can velocities get too low? How low would that be?
Yep, sounds like this might very well be a great choice for me.
The 25vna will be the match for eight zones plus warmer temps coming out of your ducts. But you seem youre in a perfect climate for a hybrid heat system.
As to the 8 zones, it might sound like overkill, but here's how my zones break out:
1) Master Bed / Bath
2) Living / Dining
3) Kitchen / Breakfast
4) Two bedrooms plus bath on front of house
5) One bedroom plus bath + utility + mud hall on rear/side of house
6) Study + Foyer (the study was a bit small by itself, so I added the Foyer, which is open to the dining and living)
7) Upstairs game/media room
8) Upstairs bedroom/bath
Does that REALLY seem like overkilll to you?
Really? When did THAT happen? You mean there's no way to get a recip compressor on the Infinity system now? It's all scroll?
Originally Posted by jasonairmaster
My brother just had one installed last year.
As of last year they were no longer made. There may be some sitting around somewhere but I doubt it. The reason why from carrier was that could not get the seer ratings up on it. Just like Trane there recips have a hard time too. The new inverter takes care of that. Sorry to break the news to you. That maybe why your brother got it at a good price becuase they were phasing them out.
Greenspeed is probably worth waiting for.
Originally Posted by jasonairmaster
I would either consider fewer zones or a smaller pump. Close to getting your head around it, but remember your house really won't need that horsepower. I have yet to see anyone get their head around how different a properly spray foamed home performs. If you've designed overhangs thoughtfully your ac load is probably overstated.
Also, it is incredibly unlikely you will EVER have all zones calling at once, so sizing under the assumption you will experience worst case load, and all zones will demand, is pretty absurd with a spray foamed house. Have a leakage target and hold your contractor to it.
Having zoning is like having a heating and cooling magnifier. This is why undersizing to 75-80% of manual j is often discussed.
For emergency/back up you can have electric or gas. This also allows you to be less concerned with having such a big pump - put your "cushion" in in the form of backup strips.
Which makes more sense to you?
- turning your thermostat back and being uncomfortable. Maybe saving 5-10%
- leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org
, or RESNET
, and find an auditor near you.