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New HVAC system

Posted by Joe_Jersey (My Page) on
Mon, Feb 25, 13 at 12:20

Looking at a new Gas Furnace and AC system.

I will indemnify myself saying that I built houses with my brother when I was a youngster so I have a little bit of knowledge of what is going on. But just a ittle.

Bought the $50 homeowner version of HVAC-Calc and ran several load calculations. My guess is that all the SW out there has somewhat of a subjectivity parameter( I call it voodoo) where you can with reasonable confidence have heat loads that vary 10K BTUs one way or the other. With that said over all the calcs I did the average was ~80K BTUs put the 20% safety fator in and 100K BTU is the magic number. The AC load was again between 2.5 and 3 Tons so 3 Tons is what I will use. The contractors come up with close to the same. Today I have a 25 year old 120K BTU furnace and 3 Ton AC which blew out at the end of last summer so hence I am replacing the pair figuring the 25 year old furnace does not owe me a dime but I am living on borrowed time. So that is where I am. Below is what I have had a contractor quote me. I have had a couple but this is where I am leaning the prices being in New Jersey is basiclly Bend over Rover from everyone. So I need to make sure the AC and furnace are properly mated in my opinion.

Furnace Carrier 59TN6 100K BTU 10/5 warranty
AC Carrier 24ANB736a 3 Ton 10/5
AC Coil Carrier CNPV 4821A 10/5
Arzel Zoning 10/10
Honeywell Thermostats

My initial concern is that the units are Infinity and I will not be able to explioit them with the Arzel zoning. Not sure how much of a premium is in the Infinity pricing but if there were a non-Infinity set which delivered the same performance I would look at that I have the contractor looking for that. I have some issues with air flow upstairs and a Family Room on a slab where the zoning appears( the operative word is appears) will help. I am not foolish enough to think that it will suddenly be a perfect environment but any improvement will be worth the price. The house is probably like a million others where the contractor put a single furnace in the basement with single trunk with feeds to everywhere with no concern as long as some point in time the house got hot enough near the thermostat to satisfy the setting.

Can someone comment on whether it is worth the Infinity pricing when I am not exploiting it. Contractor says Infinity zoning would add considerably expense for the same deliverable as the Arzel. I did a cursury check and it appears he is not misleading me. Any duct work with the way the house is built would be a considerable expense just looking at it with past experience.

I may have to look at other manufacturers but I want to stay as local as I can and this contractor appears(there is that word again)to have a conscience with a pretty impressive no small print money back guarentee with ample references.

Follow-Up Postings:

RE: New HVAC system

What size home?

What is your location?

A 100 KBTU high eff furnace with just a 3 ton AC seems odd?

You are aware that Infinity zoning is considered the best integrated system in the residential marketplace. I certainly would reconsider since you are
looking at Infinity HVAC. It just seems to me you are shortchanging yourself both on the zoning and Infinity furnace/AC as having totally integrated Infinity system including controller. I would at least go through the motion of getting the numbers.

What is the layout/design of your home and how many zones do you plan on?


RE: New HVAC system

How large is your house? Where are you located in NJ? Is the contractor a Carrier Factory Authorized dealer? Have you discussed the Carrier rebates?

If the load calculation was done correctly, then you should not be adding a 20% safety factor. This defeats the purpose of doing a load calculation. Most single family homes in NJ will do fine with a 80K BTU 95% AFUE furnace. You are probably oversized at 100K BTU.

The Infinity is Carrier's best equipment. You should get the Infinity controller. This will also qualify you for the rebate. Carrier usually starts the rebates in early March. If you are going to do zoning, then you should spend the extra money on the Infinity equipment. I am suspicious of a contractor who would discourage you from doing this.

What price quote did you get? What are you doing about a media filter?

RE: New HVAC system

House is 30 x 35 basement 1st floor and second floor so 2100 sq ft 1st and second floor. I also have a family room which is 20 x 13 260 sq ft on a slab off the kitchen. The duct work for the familiy room has it's own trunk off the furnace and it goes up the garage walls and then uses flex ducting to go across the garage ceiling and then down the outside walls to the registers(sweet huh?). 3 zones which would be 1st floor...2nd floor and the family room. There is allot of heat loss in that one room. Thoughts were to put a mini unit but I am over taxed on my breaker box as it is and the electrical run to that room being that it is on a slab is real pain in the neck even though I would be doing it myself. Plus the outside unit would hvae to sit in my wifes flower we need to say more on that?

What is the big difference of the Infinity zoning I just can't seem to grasp it with the online information.

Carrier is giving an 800 rebate and perhaps that is why the Infinity is in the scheme.

Still an infant project but thanks for the input grealy appreciated.

RE: New HVAC system


"If the load calculation was done correctly, then you should not be adding a 20% safety factor. This defeats the purpose of doing a load calculation. "

That's exactly what I thought. However the SW which I purchased clearly states to use a 20-25% safety factor. Go figure.

RE: New HVAC system

Some more answers to the questions.

House is in Northwest Jersey near the PA border.

Front faces NW and the Family room has an 8x5 window facing SE which seems to make a big difference in the calculations.

I will have an Aprilair media filter

RE: New HVAC system


First I agree with Mike & Tiger.

I question the integrity of a contractor that would propose Infinity without the Infinity controller. That’s a deal breaker for me. I would never deal with that person again unless he fully understood that we can ‘argue’ about price but that there’s ‘no compromise’ when it comes to doing things right the first time.

$800.00 rebate seems low for that combination, but that may be a regional thing.

Depending on the cost of energy, you might consider a HP over an A/C unit.

The difference the Infinity controller will make is that it’s a ‘Communicating Interface Unit’. There will be 2-way communications between the controller and the gas furnace and the A/C unit. This will enable the controller to be as ‘Smart’ as it can in that it ‘Learns’ from previous cycles to make the next one as efficient as possible. This also means ‘Smart Recoveries’ with setbacks of more than 2F. The Infinity controller will also allow for ‘Demand Defrost’ should you choose to install a HP.

Among other things, the Honeywell controller will not be able to do all these things.


RE: New HVAC system

Thanks for the info guys. Can any of you comment on the effort to do carrier zoning as opposed to Arzel being that this will be a retrofit?

RE: New HVAC system

The Carrier rebate is usually larger when the Infinity controller is included. The larger rebate offsets most of the cost of the controller.

The effort to install either zoning equipment should be the same.

Many HVAC contractors don't have the expertise to properly install a zoning system. I suggest you talk to additional contractors before making a final decision.

RE: New HVAC system

In defense of the contractor he mentioned up front we would be losing some of the Infinity Control benefits by not purchasing the Control board. I have had another person look at the ducting and to incorporate the Infinity zoning would take extensive rework since there is absolutely to room to add any new trunks which going by the Infinity zoning design "to do it correctly" it would take additional trunks. For some reason we can't get the older Carrier 58x non Infinity models delivered here which would have the varible speed blower which is an absolute neccesity. Seems you need to go Infinity in this area to get the varible speed blower. I may look at Trane or some other furnace.

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