GC should move condenser to correct location now not later...

IMO

"is it reasonable to ask the GC to finish the job, let me move back in, and then move the compressor to it's specified location? That would be the only option time-wise to get me back in the house and out of this apartment on time."

Not only is that reasonable,it's best for all concurned. You should hold final payment until unit has been moved. You are taking on more responsibility than can be expected of a homeowner unless they act as their own GC. It is not your responsibility to figure out ways of overcoming mistakes.

Pay now or pay later. Insist that the contractor move the condenser as per the contract or you'll be regretting it for as long as you live in the house.

+1 Tiger

This is what’s likely to happen if you’re unsatisfied with
the euphemistic ‘Noise Abatement’ result. The contractor will tell you, “look,
we’ve tried X, Y & Z – and you’re STILL not happy!” You’ll be the one to
seem ‘unreasonable’ at a time when the contractor may have already been paid
and you have little leverage.

As someone that works in this industry and that has done many
renovations in our own home, I stand by my advice previously posted.

There is no
substitute for getting it done right, now. Let the GC know that they will be on
the hook for your additional living expenses & have the GC pressure the
HVAC subcontractor.

IMPO

SR

If you don't require the GC to abide by the terms of the 'original contract' then why was there any contract at all?

Cost was determined by the GC was it not? In other words the cost you paid was for the Condenser to be placed where noted in the contract. Breach of contract is a losable offense on either side of the contract. There is no court in America that wouldn't award you damages with a written / signed contract that wasn't followed to the letter.

You had an agreement in writing. It should be done as specified in the contract, that's what the contract is for.

Thank you all for sharing your knowledge. I will tell the GC I want it moved.

Find out who made the decision to change the plan. Was it the general contractor or the HVAC subcontractor? Then find out if there was a good reason for the change or if they didn't pay attention to the plan.

The HVAC installer may take the easy way out and run the refrigerant lines from the unit sits now to the new location. You don't want the line to run longer then they need to be. I also suggest you listen to the condenser and make a decision if the noise is going to bother you. Some condensers are very quiet after the initial start up. It may not be worth it if walls have to be ripped open.

Hi Mike - I will ask who's decision it was to move it to the other side of the house to satisfy my curiosity, but ultimately does it matter? Running the refrigerant line to the new location really isn't an option as an "easy way out" as you can see from the attached drawing.

The mechanical has not been completed yet, so I can't listed to the compressor at this time. The schedule shows AC start up on the 10th - which I guess would be my first opportunity to listen to it - with electrical inspection the day before, and positive energy leak test & mechanical inspections the week of the 12th. If it does need to be moved, do you have an idea of how long should I expect it to take?

I would like nothing better for it to be so quiet that it's not an issue! I will check on the make & model when I swing by the house today.

Are there pros and cons to running the lines thru the attic verses under the patio? (the patio hasn't been installed yet). It seems like the attic, being hotter, would mean less efficiency, in addition to having a longer run of lines and the possibility of water damage from condensation?

In the architect's drawing that I've attached, the red box is where the compressor is currently, green is where it was originally planned. When I purchased the house it was located to the right of the double doors as you face the house. The architect and I chose to move it back from the house so that it wouldn't intrude on the patio. We planned for a water feature to provide a little white noise.

Thanks so much for any input!

I assume you have hired a general contractor to do all the work and your agreement is with his firm. The GC then hires subcontractors to do the work usually at some fixed price. If the HVAC subcontractor made the decision without permission of the GC, then the subcontractor will have to eat the cost of the move. If the GC made the decision then, the HVAC contractor will want to be paid for the work and new materials. You should find out whose fault it was. Then you will know who will be your friend when it comes to fingering point at whose fault this was.

You should have the model numbers of the equipment you are buying specified in the contract. How do you know the proper equipment is being installed?

I don't follow your question running the lines under the patio versus through the attic. I see a green box labeled AC pad that is about 20 feet from the house. I assume the air handler is in the attic. How did the architect envision running the lines from the condenser to the house? Maybe this is the reason the condenser was relocated so it is next to the house?

Ah. I assumed that it was possible to run the lines in the ground away from the house because of the architect's plan. The details on the AC install were left to the contractor. Again, no questions were ever raised from anyone about that so I have been assuming that this was not a problem. Judging from your response, I'm guessing that this is never done. Yeah, this should have been discussed before the thing was moved, but I sure am feeling a little stupid...

Probably moot at this point, but the air handler is in it's HVAC closet (green on the drawing). The house is a 50's ranch with a low attic clearance - no room for much up there.

Again, many thanks for your responses!

I think it would be possible to run them under the patio. They would have to be inside piping to protect them. This something that is typically not done. Maybe the HVAC subcontractor did not want to take on this task.

I agree with Austin Air. If the contract documents specify where the AC is to be placed, he is legally liable for moving it to the right location. If it is not spelled out or if you are unwilling to wait, you may want to consider one of the quieter AC units. Most manufacturers' 16 SEER and up units are very quiet; all except for Trane that is. Just a thought. I always say that they are all pretty much alike. I may have to eat my words now, but as far as sound, I like Carrier and Amana. They are both very quiet.

I just heard back from my architect when I asked him about this: "Right now, the refrigerant lines are a relatively long run up and over the house through the attic, but they are concealed for the most part. The original placement of the condensing unit (away from your bedroom) would be a much shorter run for the refrigerant lines and would be more efficient, but getting them out of that closet and into the ground would expose them for a short run, which might be unsightly. If you placed them on the ground, and built a deck over them, that would work. If you do a patio slab, they would get buried in a plastic pipe sleeve, just like we have done in concrete slabs forever." So it looks like it's not a big problem to run under the deck. I'll discuss with my GC on Sunday. Thanks again!

Go for "unsightly" but NEVER put refrigerant lines under a slab, even if they are in a sleeve. The underground lines will be cooler and will have a definite tendency to collect refrigerant oil and refrigerant that should be circulating in the system. This will ABSOLUTELY cause future problems. Refrigerant lines should always be above ground, always, always. If you can opt for the shorter run, that will be beneficial to your system longevity and efficiency. Just keep the refrigerant lines above ground. Give em heck!

I just thought of something regarding the time it would take to move the unit and get it up and running...currently the lines are run through the attic, but do these necessarily have to be removed before the compressor itself is brought back to the other side of the house? The HVAC closet opens to the patio... the access to the air handler is from the patio, not from inside the house - the door is indicated in the drawing I uploaded. Might it be a pretty quick job to move the compressor and install new lines to the correct location and get things up and running ASAP, and then remove the old stuff running to the new location when time allows?

Air and Energy - "Just keep the refrigerant lines above ground". Is on the ground considered above ground in this case? I could do a wood deck and run the lines under the wood deck on the ground if on the ground is an ok place for the lines.

Carrier's website lists "24ABC636A003" as the 16 SEER. This is a "24ABC636A300". I can't find this model on the website. Are you familiar with it?

Try this link. It is the product data for this machine. Looks like it's a 16 SEER. The link is HERE. Hope this helps.

The two Carrier condensers you listed are the same. I think the 003 and 300 suffixes are minor variations. The internal components are the same.

The SEER rating derived is for the system of the condenser, coil, and furnace or air handler. This condenser has the potential to achieve a 16 SEER rating when connected to a the AHRI matched components.

There is a sound hood available. You should look into it.

It is interesting the sticker says the condenser can't be installed in the southwest. Anybody know the reason for that?

There is no problem putting refrigerant lines in the ground as long as you enclose the copper line set within protective tubes and 'properly' seal the tubes at both ends. There should be no brazed connections on the line set within the under ground 'protective tube'. (it should be a continuous copper run properly insulated with no joints.)

When the compressor (outdoor condenser) is installed above the indoor evaporator then can there be oil return issues. Systems can be installed this way but special loops must be installed to ensure proper oil return. (Think commercial or apartment complex with AC units on the roof and indoor evaporator coils within the structure. - this doesn't apply here.)

A longer line set run is more detrimental to oil return issues than running a line set 6 inches under grade. Problems often develop with these when not installed in protective tube or the tube is not sealed properly.

Hmmmm. At 76 decibels, it looks like my ac is the loudest Carrier makes. I don't really have a frame of reference... Is 76db loud? Is 72 or 66db noticeably quieter?

It is interesting the sticker says the condenser can't be installed in the southwest. Anybody know the reason for that?

My suspicion would be climate differences. 'Southwest includes all of the Arizona desert.'

Holly, noise is subjective. What bothers one person won't bother another.

A two speed condenser is considerably quieter than a single speed condenser.

Because it will operate upwards of 90% of the time in first speed. When the 2 speed unit engages 2nd speed it's as noisy as a regular single speed AC. Usually this is in the heat of the day 3-7pm.

This condenser you posted is a single speed AC.

The carrier website says "Some models in the Comfort™ Series may not be eligible for installation in the Southeast or Southwest regions of the country, based on Department of Energy minimum efficiency standards in place as of January 1, 2015."

The new rule is the SEER rating is a minimum of 14 for the southern states. This condenser should meet that minimum. That's why I was questioning it.

The Comfort series is Carrier's budget condenser line. It tends to be noisier than the Performance and Infinity series. You can't go by the noise specifications. I don't think there is a standard how noise is measured for AC condensers. But the relative ratings within the same manufacturer should be consistent. You would notice a 10db difference.

Based on your diagram, I can guess why the contractor chose to move the compressor. It is now located next to a closet and bathroom (not the bedroom itself), which should provide some sound isolation from the bedroom. If you left it where it is now and installed a noise barrier/absorption structure around the "North" and "West" side of the compressor, you could probably absorb or redirect most of the noise when it is running. You could also upgrade the windows on that side of the bedroom to ones that provide better noise isolation.

By moving the compressor to the "West" side of the patio you shorten lines to the inside unit, but have added new challenges. You already discussed the need for long coolant lines running under the patio, which is not typical, since most home A/C compressors are located within about 3 feet of the structure. In the summer you will also have a constant noise generator right next to a patio where I expect you want to sit outside and enjoy the weather. It will be relatively difficult to stop/absorb the noise from a compressor that is only about a foot away from an open patio.

If you relocate it to the patio side you may need to box the compressor in on 3 sides with a noise-absorbent barrier that extends a foot or two above the compressor. As long as there is sufficient space around the compressor for it to pull in air, and an open top on the enclosure, it should still work fine. The sound absorbing material on the inside of the enclosure muffles some of the noise, and a large part of the remaining sound is redirected up and toward the open side of the enclosure. I've seen similar solutions used with generators to reduce noise, and I assume it will work with an A/C compressor.

Bruce

Hi bcarlson - Thank you for your thoughts! The compressor is just 6ft away from the bedroom window. It's an old house with old insulation and new double pane lo-e windows. There's a remote possibility the noise won't be a problem, but I find that even the noise the refrigerator makes bothersome sometimes, so it's iffy.

Noise on the patio isn't such a big issue since I'm not trying to sleep on the patio. Summer isn't really a time to enjoy the weather on a patio here in central Texas, anyway, so that's pretty low on my list. Though a sound barrier as you mentioned here would be useful to not only quiet my compressor, but to quiet my neighbor's compressor since his is just on the other side of our fence.

Thank you all - this has been so helpful & I'm so glad you shared this info before my meeting with my GC!

-Since the compressor was installed in the wrong location as clearly indicated in the architect's drawing and that location was chosen specifically to have quiet in the bedrooms and to promote efficiency of the AC...

-Since the unit that is installed is one of Carrier's loudest (I found a reference that 76 db is somewhere between a vacuum cleaner and garbage disposal.)...

-And since the unit's efficiency will be impacted by the long run in the hot attic...

I will offer the CG two options:

1) He can either move the existing unit to it's originally specified location with the copper line set within protective tubes and properly sealed at both ends and no brazed connections on the line set within the under ground 'protective tube', per Austin Air Companies advice (to bad you weren't actually IN Austin - I'd hire you!)

2) He can replace the system with a higher efficiency unit that runs no louder than 70db and keep it where it is with additional noise remediation/sound barriers as needed.

I'm pretty sure he'll go with option #1. If his AC install guy isn't familiar with this type of installation, should I be able to select who installs it? How can I ensure that it is installed correctly?

I'm also pretty sure he'll threaten me with lengthy delays impacting my scheduled move in on the 16th. What is a reasonable time frame to move or update the compressor? No inside walls have to be opened up to access the compressor or the air handler.

Can you think of anything else I should be prepared for that we haven't discussed here? I am going to stand firm that he is legally liable to move it. To answer an earleir question, I was not provided with any information regarding the model of the AC that was selected prior to installation.

thanks again!

What is a reasonable time frame to move or update the compressor (condenser).

I could make the change within 24-48 hours (no weekend delay either), by myself - no subs, no techs, no delays. Then again if I was involved we wouldn't be having this discussion to begin with.

If his AC install guy isn't familiar with this type of installation, should I be able to select who installs it? How can I ensure that it is installed correctly?

If you're able to choose I doubt it would make much difference. Builder's sub contractors / Renovator sub contractors are geared differently than 'true' HVAC service companies. You'll see this more clearly if it takes them longer than 48 hours to make this change (whatever it is.)

Can you think of anything else I should be prepared for that we haven't discussed here? Make sure the unit is registered so you get the full manufacture warranty, make sure it is cooling properly in all areas of the home after it is moved. Personally, I would avoid placing anything around the unit for sound proofing. There are good reasons for this, but I won't get into this here.

I think installing the condenser at the far end of the patio is risky. You will have a difficult time finding someone who will do it properly, and then there would be no guarantee when it fails in the future.

I think the GC would want to upgrade the equipment before spending all the time and money on moving it. Ideally you would upgrade to a Carrier Performance 2-stage condenser. Are you also getting a new air handler and coil? If not then you will be limited to what condenser you can use.

If you are going to move it near the patio, then shift the patio so you can place the condenser next to the air handler. You can construct a wooden lattice so you don't have to look at it.

Hi mike_home - yes, it's an entirely new system. Apparently I have a Honeywell Media Air Cleaner, a Carrier CNPVP/CNPVT (coil?) and the Comfort 24ABC636A300. I would consider moving it to the left of the air handler closet if that location had serious benefit. (you can sort of see the AC closet here- its between the white double doors and the small window). I would also consider moving to to run along side the little carport shed if the location shown in the drawing was/is a problem.

I met with the GC this morning and brought up the air conditioner placement. I asked him who's idea it was to move it to it's present location when it is clearly marked on the plan where it was supposed to go.

His response was that 'architects put these things in the drawings randomly' and the locations in the drawing don't mean much. And since it was an unusual location, he and the HVAC guy got together and decided where THEY thought it should go. He claims that he moves things like this 'all the time' and its 'to be expected', which is why he never asked me about it.

Then he claimed he moved it because he 'knew the budget was tight' and he didn't include running line underground in the estimate. Is running a short underground line that much more expensive than running a long line through the attic?

I pointed out that the unit was there in the drawing he based the estimate off of, so he fell back on the architect's drawings aren't meaningful in terms of placement of these types of things.

Does this make any sense to you?

I have big concerns now about the noise since the unit is maybe 6 feet from my window and it happens to be one of Carrier's loudest compressors, listed "as low as 76db". I looked up what 70 and 80bd means: somewhere between a vacuum cleaner and a garbage disposal. I mentioned this to the GC and in typical condescending fashion, he said 'don't believe everything you read on the internet".

He offered to think about moving it back further towards the corner of the house towards the bathroom, which I'm not convinced is a satisfactory solution regarding the noise, and will make it even less efficient (he claims this isn't an issue). I said that if the unit proves to be too noisy, which it is likely to be, then it will have to be moved to it's original location.

I also pointed out that if we move it later, it'll be more expensive since all the refrigerant lines will be charged.

He wasn't at all happy about that, so we left it with him to provide me written assurance of what his company will do to remediate the situation to my satisfaction.

I HAVE to move back on September 16th and simply don't know how to deal with being told bald-faced lies like this AND get the project completed to my satisfaction on time.

This has been a learning experience- after meeting with the architect last week, I learned I should have been provided with a schedule and a spreadsheet of expenditures to date (I had been creating my on spreadsheet). I have since requested and received those. I did not recieve model numbers of the AC and water heaters, and since those are both installed now so that point is moot.

This is my fourth home remodel and the only one that I have not served as my own CG. I have never had any issues with the previous projects - all my subs were great. Somehow I thought that by hiring a GC, I would be hiring an ally that would work to advance my project with my benefit as a priority.

I emailed my architect today to see if he'd be willing to supervise project completion. Hopefully I'll hear back on Monday. I have also been in touch with someone familiar with construction law. I was really hoping to avoid this kind of static.

“His response was that 'architects put these things in the
drawings randomly' and the locations in the drawing don't mean much.”

Such nonsense! How can anything
be built to spec if, “locations in the drawing don't mean much”? Everything
in architectural drawings mean exactly what’s indicated!

A 10db difference in sound (noise) level means that the unit
with the higher number (+10db) is twice as loud – very significant - particularly in your case where even the sound
of a refrigerator can be bothersome.

Your system hasn’t even been charged with refrigerant at
this point, very easy to move; particularly since the new line set will be so
short. The existing line set can just be properly terminated and just abandoned.
The new line set can be run through concrete or underground if necessary, as
long as it’s done through a proper conduit, terminated at both ends of the
conduit (as previously mentioned in another post) with the refrigeration lines
properly insulated with ‘Armaflex’. Brazing if properly done should not matter,
however it is best when kept to a minimum.

Personally, I think a better choice would have been the
Carrier Greenspeed condenser (24ANB136A003) and matching FE (FE4ANF003L00) series
fan coil, everything variable speed, as quiet, efficient and flexible as possible.
I would also suggest taking an extended warranty, parts & labor, if possible.
That way if things go wrong you won’t be on the hook for it!

IMPO

SR

Looking at the photo you posted, I would think installing the condenser in the corner underneath the bathroom window would be the best spot. It needs to be about 3 feet from either wall. You could construct a lattice structure on the other two sides to hide it. Then you can build the patio around it. This keeps the installation simple and the the lines to the air handler short. I can't understand why the GC didn't propose this instead of moving it to the other side of the house without asking you.

I do think you should get something better than the Carrier Comfort condenser even if you have to partially fund it.

"Don't believe everything you read on the internet."

That's true, even on this website... but your situation is breach of contract. You have a contract that specifies what is to be done.

Architects don't get paid to just stick things where they want on a drawing. It's called a blueprint.

Print out the page of the link below and give it to GC.

Legal remedies for breach of contract.

You need to carefully read the contract you signed to see what it says about changes to the architect's drawing. I would imagine there is a big loop hole about it. Do this before you start getting your lawyer involved. Once you start the lawyer conversation, all work will stop and then you have no leverage about moving in on time.

I am very grateful that the architect has agreed to deal with the GC now. The compressor will be moved to its specified location. Frustrating having to employ someone to oversee the person employed to oversee the project. I am hopeful that the last remaining bits will go smoothly & be completed on time. I wish I could upgrade the equipment but since it's already on site and the air handler is installed, changing it out would be a big deal. Thanks everyone!

Holly that is probably the best outcome one could hope for. The purpose for legal remedy is always a last resort when all other options fail to deliver.

This GC will hopefully realize the error of his ways and you may have saved someone else from a big mess.

We're still in negotiations about this...can you tell me the approximate cost difference between the Carrier Greenspeed condenser (24ANB136A003) and matching FE (FE4ANF003L00) series fan coil - or similar quiet combo - and the Carrier Comfort (24ABC636A300) and the matching coil (CNPVP)? The GC has offered to upgrade the condenser to the 24ACC636, which he says is the only option that matches the coil. The difference between the one he is suggesting and the one that is installed is only 72 vs 76 decibels. I would consider leaving it where it is if there was a quiet option that we could use, even if I had to fund the difference if it were within reason. There may be some limitations with the coil as it has to fit in the HVAC closet...

The 24ANB136A003 is not the Carrier Greenspeed condenser. It is the Infinity 2-stage 19-21 SEER model. The Greenspeed is the 24VNA9 which has 5 stages and a low of 56 decibels. Both of these with the variable speed fan coil are very expensive. I am going to estimate an additional $2000, but I could be wrong.

I think a good compromise would be the Infinity 24ANB6. It is the single stage Infinity condenser with a noise rating of 66 decibels. It should not require a variable speed air handler so it may work with what is already installed. This can be verified on the AHRI directory.

According to the GC "Upgrading unit has only 1 option that will partner with the existing furnace/blower unit & duct lines". (I don't know enough about ac to be able to verify through the AHRI directory.) According to the Carrier website, the 24ANB6 might not be the best choice for Austin TX ("Northern climates with less humid, milder summers may not call for the highest degree of efficiency")...

I think what it comes down to (and what you have been telling me all along), is that it's MY house and I should be able to decide the AC that I want. So, for the proposed budget of $8,700.00 for a 1,600 sq ft home, what is a nice, quiet Carrier heating/cooling combo that fits within the budget?

Holly,

I am not sure which thread you want the answer to your questions. I am putting it hear since this about to come to a conclusion.

You wrote in your other thread:

"Equipment Upgrade: 1 stage 16 Seer Carrier Infinity with 66dba sound

With this equipment & install, we will have to remove sheet rock out of the bed 3 and master closet to change the duct from a 4" to a 5". $4,458.02 not including sheetrock/paint/house protect.

FYI: It would be reasonable to assume that any 2 stage unit or any 1 of your requested 17, 19 & 21 Seer units would not only be more expensive, but could require more duct size changes with the additional trickle down additional sheetrock removal etc."

is it true that the ductwork would have to be upgraded as well? Can inspections for everything else be done so that I can occupy the house while the HVAC debacle gets addressed?

Is the the 24anb6 single stage condenser? Will it also be 3 tons?

A better condenser will be more money, the question how much more should you have to pay above the original HVAC budget. Only the GC can answer this question since he has all the costs.

If the old and new condenser are the same size, then the duct work should not have to be changed. Both condensers should have about 1200 CFM of air flow. What really makes no sense is why one duct in the bedroom has to change from a 4 inch to a 5 inch size. Not only does it make no sense, I seriously doubt you have a 4 inch round duct inside your wall. It can't fit in the wall cavity, and a 5 inch would not fit either unless there is a chase built in the closet or bedroom.

I think the GC is trying to justify the extra $4,458.02 (the estimate is down to the penny) and making up additional work. In additional you have to pay for new sheetrock, painting, and house protect (whatever that is).

Maybe I am completely wrong about this, but the whole situation is unfortunate and sounds fishy to me.

There are likely cost changes when you start going outside the confines of the original contract (changing things costs money and the amount will vary from one contractor to another). This talk about increasing a duct from 4 inch to 5 inch is just trying to justify the cost of those changes.

If you don't like the additional cost just have them put the condenser where you originally wanted it.

(Sorry for the confusion about which post to reply to - I'm not familiar with forum ettiquet and had started a new thread when I should have stuck with this one).

The 24anb6 is a single stage. All conversations are centered around a 3 ton unit. The ducts are in the attic space. The original house was 1140q ft. The addition is about 488q ft.

The original house (1950s) has a metal ducting trunkline system that runs in a dropped ceiling in the 12' long central hallway. The new ducting is in a jumble in the attic of the addition, with a big box thing (a baffle?) and 4.5" ducts curling around everywhere - even back to the front rooms of the original house. Apparently code has changed and new 'jumper' vents needed to be installed in all the rooms?

Before that ceiling was closed up, I got a glimpse up there and noticed that it looked like and orgy of Robby the Robots - probably not the most efficient thing ever.

If it's true that with the ductwork currently installed would not support a more efficient unit in the future without ripping out walls, I think this makes an even stronger case for upgrading the equipment now. (I work at home and I plan on living at this house a long, long time.).

I was told when to pick out plumbing fixtures, hardware, lighting, etc...I guess expected to be told when to decide on the other choices involved. If the GC had asked, I could be looking at paying 10 or 11K for exactly what I want - a 2-stage, high-efficiency, quiet unit. Instead I'm having to choose between paying nearly 9k for stuff I don't want or - it seems from this email - paying twice for the install and associated repairs in addition to the upgrade.

I'm going to push for exactly what I want. The GC is working up estimates for the Carrier Infinity 17, 19, and 21 SEER units. I have no problem paying the difference in the cost of the equipment, or even the cost the have the install done 'right', which I assume means moving the trunkline up to the attic and having a single trunkline.*

I'm sure things will get sticky when we start discussing who pays for what. It would be so helpful to be able to get objective estimates from a neutral party on what the original install should have cost and what the install that I'm requesting will cost. Is that ever done?

I'll post any progress as it happens. Thank so much for your feedback. It has so helpful in getting clarity on this situation!
************
*The email I received this morning regarding my request to move forward with the estimates for the 17, 19 and 21 seer units: "The 17,19,21 Seer units besides being even more expensive will likely require more duct replacement, more sheetrock removal, etc. as this will snowball the work; time frame would increase accordingly. " and "Regarding the duct work replacement, it should be noted that the metal ducting trunkline system & some ducting that pre-existed in your home is still in place & that airflow supply system may need to be upsized as well, as the Seer rating increases, expanding the scope of other sheetrock & installation repairs as well." It would seem that he really doesn't want me to upgrade...From what I can gather the difference in cost of the equipment between the builder-grade Comfort series and the Infinity series is about $1,500 - about 1% of the total project cost.

"If it's true that with the ductwork currently installed would not support a more efficient unit in the future without ripping out walls, I think this makes an even stronger case for upgrading the equipment now."

The statement is not true. The role of the duct work is to transport a volume of air at a given speed. The air flow is measured in cubic feet per minute (CFM). The efficiency of the condenser measured is a measure of how many BTUs of cooling are produced per unit of energy (electric Watts). That efficiency is rated in SEER and EER. The same air flow can be produced by a condenser rated at 13 SEER as well as 19 SEER. The duct work performance is not tied to the efficiency of the condenser. They are independent of each other.

Now if the duct work is in poor condition, and the GC and HVAC contractor have decided to fix it as part of the condenser upgrade, then they should be honest with you and explain what they intend to do. But they should not be making up estimates and say the work is needed because a Carrier Infinity single stage condenser is more efficient than a Carrier Comfort single stage condenser. If that is the case, then have them sit down with pencil and paper and describe the physics supporting their argument.

Thanks so much for the explanation!

mike_home - is there any reason the ductwork would have to be upgraded for a variable speed or two-speed compressor?

“Is there any reason the ductwork would have to be upgraded
for a variable speed or two-speed compressor?”

Ductwork should always be properly sized for the CFM to be
delivered by the size of the equipment being installed. You can calculate
400CFM per ton. However, to answer your question, if you’re installing a
Carrier Infinity system, the fan coil unit will ‘analyze’ the ductwork it’s
hooked up to and self adjust. So there might be less reason to modify existing ductwork, as the system will still
deliver the correct CFM (within limits).

Keep in mind that there is no substitute for good/proper design & installation.

IMPO

SR

You should ask the GC what he means by "upgraded". Is he talking about changing flexible duct into hard ducts?

I agree with what fsq4cw has stated. In addition the Carrier Infinity can be programmed to run at 350CFM per ton. Another reason for not having to make the duct work larger with this system.

Thank you, thank you, thank you! It's so helpful to have accurate information when making these decisions!