Lexmom

All of these models are listed on the Carrier HP website.

All of these systems are listed in the AHRI HP Directory with performance and efficiency numbers.

The first and second quotes have same condenser, different air handler-fixed speed vs var speed, different size heat strip, and a plain HP thermostat vs a Carrier thermidistat.

The third option is a higher SEER HP condenser. Everything else same as option #2.

What is your location? I question the size of the heat strip for a 3 1/2 ton system unless you live in a very southern location with mild winter climate.

Links listed below.

IMO

http://www.carrier.com/homecomfort/en/us/products/heating-and-cooling/heat-pumps/split-system-heat-pumps/

http://www.ahridirectory.org/ceedirectory/pages/hp/defaultSearch.aspx

Have you decided not to install a gas for the first floor? I am confident the operating cost of a 95%+ efficient natural gas furnace will be lower than the heat pump and electric strip combination.

For lexmom

Just to clear, do you natural gas service to your home-nat gas not propane?

If you do have nat gas, I would install a high eff nat gas furnace or an 80% nat gas furnace with high eff heat pump.

IMO

Thanks tigerdunes, I'll look again. We're in central SC, mild winters. We foamed the roofdeck (upstairs ductwork and airhandler are in the attic) and upgraded the rest of the insulation. We had a manual J calculation done which took some time for them to get right but I think they put in the right info in the end.

Yes, we have natural gas and NG is specified in our contract. It was changed in the contract so maybe that info didn't make it to the hvac contractor. I just sent a message to our contractor and he said that he'll let them know.

Any recommendations on a system? Looking for a 10 yr payback on any upfront costs.

Lexmom

To be clear, is this new construction or a renovation with upgrading your HVAC?

If you have nat gas service, I have given you my general recommendation. That would be high eff furnace with 15 SEER min AC or 80% eff vs two stage furnace with 15 SEER minimum heat pump.

Your comment about a 10 yr payback on a new system is unreasonable and probably not possible. No offense intended. I would need to see what exactly you have now both heating and cooling with efficiencies to even make an educated guesstimate.

IMO

Tigerdunes,
Yes, new construction. No offense on the 10yr paybak, but to be clear, by payback, I mean the 14 SEER is $1,000 more than the "standard" 13 SEER so if I am spending an additional $1,000 upfront, I am looking to recoup at least that amount in reduced AC costs over the next 10 years. Are you saying that is not probable? If not, I don't know why I'd upgrade to a higher SEER.

At most, you would gain up to 5% savings on each 1 pt SEER increase in efficiency. That's for AC alone.

If comparing heat pump heat versus nat gas heat, that would involve more details such as rates for electric and nat gas plus efficiencies such as COP for heat pump and furnace efficiency.

And just my opinion, but I would not purchase a new heat pump system without a var speed air handler or a new furnace without a var speed blower. This gives you better comfort in AC cooling due to improved dehumidification. And SC has high humidity in the summer.

IMO

Lexmomof3,

This is your fourth thread on the same topic. You are making it difficult for posters to follow the information you have already provided. It is best to keep one thread going so there is a running history of information.

If you are looking for low operating costs and saving money on the initial installation then I recommend getting a 95%+ efficiency gas furnace and AC for the first floor. If the second floor furnace will be installed in the attic, then a good option would be an 80% efficiency furnace with AC. You could get a heat pump for the second floor, but you would need to look at the gas and electric rates to determine how long the pay back period with be. I recommend furnace and AC combination that gets you in the 15-16 SEER range. Multi-stage variable speed furnaces are very nice, but they tend to be expensive. Carrier is now offering the spring rebates. Upgrading to a Infinity model may not be that expensive because the rebates are bigger.

Has the contractor recalculated the heating and cooling loads? In your other thread you stated the cooling load for the first floor came out to be 3.79 tons. Why is the contractor proposing a 3.5 ton AC? I feel he is guessing again. This is the guy who first wanted to install a 5 ton unit. I also can't believe he has not proposed installing a gas furnace. Is the contractor a licensed plumber?

Did you talk to the builder about getting another HVAC contractor?

One thing Lex - 10 year payback is a reasonable proposition but the equipment should last quite a bit longer than that. Given low mortgage rates and little safe way to get good returns on invested capital, a more logical payback period might be 15-18 years. And as I've said before - there are often other differences other than efficiency between units. It is telling that almost everyone on HVAC forums recommends going to seer 15 in the South.

I am pretty confident that in SC, a seer 15 makes sense. But it does depend on your house. Mostly window count and orientation.

Are those upgrade charges just for the downstairs? They seem very pricey.

Are you a negotiator? I'd consider offering $1000 extra for the Seer 15.5 - take it or leave it... I don't have access to prices but I suspect it is about $700 more to the installer.

mike_home, you're right that it does make it difficult when I have several threads regarding the same situation. The contractor did do a new manual J calculation. The original one was done with the plans and factored in foaming the roof deck but didn't take in alterations to the plans that we made or upgraded wall and floor insulation nor the low e windows. After recalculating, we came in at 3.1 something for the downstairs and 2.3 something for the upstairs. So in the end, we went from a 5 ton for the downstairs to a 3.5 ton and from a 3 ton to a 2.5 ton for the upstairs.

I did ask my builder about using another hvac contractor and he didn't really want to do that. This company has already started the duct work (just holes for vents and bathroom fans so far). He insists that this company is the best around and they do get all As on angies list (FWIW). But, I also know they are more expensive because we had a carrier unit replaced just a month before we closed on our last house (died after inspection but before closing) so I sent that contractor the specs and his price was closer to $700 more for the 14 vs 13 seer. We do want to get to the 15 seer so I may try to negotiate. And yes, the $1000 is for upgrading just one unit so $2000 to upgrade the downstairs and upstairs units from a 13 to 14 seer and $3600 ($1800 each) to upgrade them to 15 seer.

Regarding the rebates, from what I found, the rebates only apply to replacing an existing unit and not to new construction. I found the following on another website, not the carrier website. I didn't see much in the way of details on the carrier website.

"The 2013 Carrier Cool Cash rebates are available for systems that are sold as a replacement to an existing residential system, or as an add-on in a home that already has an existing heating and cooling system. The rebates do not cover purchases of HVAC systems for new construction, multi-family or commercial applications.":

You are right, it does state new construction is not eligible on the Carrier web site. I always assumed new construction was included. Sorry about the error.

Here is a link that might be useful: Carrier rebate program rules

I contacted our builder and now the hvac contractor has updated the quote to include natural gas for the downstairs unit as our contract states. He said that he quoted a "split gas system" but I'm not sure what that means. Is that the same as dual? What are the advantages/disadvantages to what he is proposing?

14 seer with variable speed blower ADD: $1,000.00
Outdoor: 24ABB342A003
Indoor Furnace: 59TP5A100E21-20
Thermidistat: TP-PRH01-A

15.2 seer with variable speed blower ADD: $1,750.00
Outdoor: 24ACC642A003
Indoor Furnace: 59TP5A100E21-20
Thermidistat: TP-PRH01-A

The 59TP5 furnace does not have a variable speed blower. I'd hope you aren't being told that it does.

This post was edited by ryanhughes on Mon, Mar 25, 13 at 14:18

ryanhughes - I haven't had a chance to look up the specs yet so I appreciate you pointing that out.
Honestly, I'm not sure what I'm being told. I copied and pasted exactly what he emailed to me. I assumed that the system was variable speed as that is what is next to the seer rating. Is the ac part of the system variable speed but the furnace not variable speed? Or is none of the system variable speed? We're in SC, hot/humid climate if that makes a difference.

When you talk 'variable speed', you are talking about the blower which is part of the furnace.

If you could only do higher SEER on one system, I would do the upstairs. That's where you're going to be running it a lot (assuming upstairs is occuppied in summer).

To me, this seems like a big jump in price for a small jump in SEER at these levels. But I don't know the prices.

Are you getting a discount for adding foam insulation in the attic? There is a big price difference between a 3.5 ton and 5 ton condenser and all the required ducting that goes with it.

The HVAC contractor is proposing 100K BTU furnace for the first floor. What was the heat load calculation? This sounds oversized for a house in the south.

This is a nice single stage furnace. Carrier's gas comparison chart says it is variable speed. However I believe it has a high eff blower motor rather than a true var speed blower.

I certainly would want to see the load calcs in writing.

Hard for me to believe you require a 100 KBTU furnace.

This is quite typical of GCs and their dealers to oversize, overcharge, and take advantage of their customer.

IMO

Here is a link that might be useful: Carrier Furnace

Below is what we're considering. We received a $2,500 credit (to use towards upgrades or cash back). The additional amount listed by each unit is the amount we'd have to use of our credit to upgrade from a 13 seer unit. Upgrading to the 15 seer would be an additional $800 for EACH unit which just seems pretty pricey for the incremental increase. We want the variable speed both upstairs and down if possible.

I'll post a copy of the summary from the manual J calculation. I'm not really sure how to read it but for the furnace, would it be the "htg CFM"? If so, it says 656 downstairs and 467 upstairs.

3.5 ton split gas system DOWNSTAIRS ADD: $1,000.00

14 seer with variable speed blower
Outdoor: 24ABB342A003
Coil: CNPHP4221ALA
Indoor Furnace: 59TP5A100E21-20
Thermidistat: TP-PRH01-A

2.5 ton split heat pump UPSTAIRS ADD: $1,000.00

14 seer (ARI# 3701069)
OUTDOOR: 25HBC330A003
INDOOR: FV4CNF005T
HEAT KIT: 9 KW
THERMIDISTAT TP-PRH01-A

CFM stands for cubic feet per minute. This is the amount of air flow the system needs for heating. It is used to calculate the sizes of the main duct.

It looks like the heat losses for the first and second are 33,427 BTU and 25,286 BTU respectively. The HVAC contractor has proposed a 100,000 BTU furnace (about 95,000 BTU output) just for the first floor. This is almost three times the required size. Why generate a load calculation if you are not going to use the data?

I am losing my confidence in this HVAC contractor. I hope this is not an indication of the quality of the installation.

Ah, I see that.

Per Carrier website:
CAPACITIES
40,000-120,000 Btu/h

So, given that we need less than the MINIMUM, I would say this is oversized for sure. Any advice on what is proposed for the second floor?

Also, what should I look for in the duct work? I don't know how I will make sure they did that right.

I appreciate all of your advice. I'm the type that, although I have no idea what I'm really talking about but I ask questions and try to learn. Given my experience with this hvac contractor, I get the feeling as though they've never been asked these questions by a homeowner before.

I would suggest also getting a furnace for the second floor. If it is going in the attic then a 80% efficiency model would be the safe bet. Carrier does not have many choices in the the 40,000 BTU size. The Performance Boost 58PHA is one option, but it is a single stage unit. The output would be 32,000 BTU. If you upgrade to a 2-stage model, then I think the only choice may be the Infinity 58CVA. This would be a 70,000 BTU input with a 56,000 BTU output. The furnace would operate in the low stage most of the time. It is a variable speed so you could achieve a higher SEER rating.

Mike, could you explain the benefits of going from the proposed furnace to the Infinity 58CVA? Is it just better efficiency or are there other benefits? Is the proposed furnace a problem other than it is oversized for our needs? I'm just trying to understand why I need to ask for one over the other when I talk to the hvac contractor tomorrow. Anyone have any idea of the cost of the proposed furnace compared to the Infinity 58CVA? Thanks!

The Infinity 58CVA is a 2-stage variable speed furnace. Variable speed means that the blower motor will operate at whatever speed is necessary to push the required air flow through the duct work. So when as the filter gets dirty, the blower increases the RPMs (revolutions per minute) to compensate for the dirty filter. The furnace will also let you know when the filter is dirty and needs to be changed.

The great benefit comes in the summer when the blower can slow down to improve the removal of humidity. You will need to get the Infinity controller (thermostat) in order to take advantage of this and other features the furnace can provide.

I was suggesting the 58CVA as a possibility for the second floor. Right now the contractor is suggesting a heat pump only. The first floor 59TP5 is a 96% efficiency furnace. Installing this furnace in the attic could be a problem since it produces water condensate which could freeze. It can be done, but you have to trust the HVAC contractor knows how to do this properly. Furnaces which are 80% efficiency do not produce a water condensate and can be installed in attics.

A good contractor should propose the good, better, and best options to the customer in a clear enough manner so the homeowner can make an informed decision. I hope this contractor sits down with you and explains all the details of the various options.

Mike, thanks for the reply. One question about the upstairs heat pump. You said, "Installing this furnace in the attic could be a problem since it produces water condensate which could freeze" Do you mean, freeze in the attic? If so, we're in central SC and our attic has open cell foam insulation.

Yes if an attic is not insulated then the water drain line could freeze. If you going to foam the roof deck and the fact you are in SC, then your attic should stay above freezing. I would check with the builder about this. I don't want to give you wrong information.

Thanks. The roofdeck is being foamed as we speak (or type). I don't think there's much chance that it will freeze in the attic. I just wanted to make sure I understood where you were talking about.

Now I'm wondering if I even need gas heat. That is what I'm used to and felt it was superior. Builder says that as long as you put a good system in and insulate properly (we have above code insulation), heat pump is fine. I think the gas furnace he proposed is about $1,100 more than the electric.

When I asked about the furnace, this was his reply, "This is the smallest furnace that is variable speed and will get you to 14 seer. If I was to drop to the 80,000, it would drop the seer rating of the system to a 13.2."
I've asked about the infinity model suggested here.

Here was his response. "You need a furnace that is at least 90% or more because of venting. With the 58 CVA you would get a furnace that is only 80% efficient."

Any advice?

Here are two AHRI matches which has the 60,000 BTU furnace which will provide achieve a SEER of 14 (last number in the string).

4816242 Active Systems COMFORT 13 PURON AC CARRIER AIR CONDITIONING 24ABB342A50 CNPH*4321A** 59*P5A060E17**14 41500 11.50 14.00

4816334 Active Systems COMFORT 13 PURON AC CARRIER AIR CONDITIONING 24ABB342A60 CNPH*4321A** 59*P5A060E17**14 41500 11.50 14.00

The 59TP5 furnace is multi-speed and not variable speed.

There are many more matches using a different coil model which will produce a SEER of 13.7. You are not going to notice a difference in your electric bills between a SEER of 13.7 and 14.0. An over sized furnace will be constantly cycling and run inefficiently. You are much better off having the proper sizes at slightly lower efficiency.

I don't understand his point about the 90% furnace and venting. He is going to have to explain this to you in detail.

My advice is to meet with this contractor in person and go over all the options. The first priority is properly sized and installed equipment. You can achieve a higher SEER but it is going to require a more expensive furnace and AC condenser. I get the impression this contractor does not want to spend time analyzing the furnace and AC combinations to find something that would be the best fit. Perhaps the builder is squeezing him on the price and he feels it is not worth his time and effort. I feel your frustration as I would also be very frustrated.

For those following this thread, have you taken the time to review the load calc that OP posted for both the downstairs and upstairs zones?

IMO