What system did you finally install? Mdl numbers and size please?

IMO

OK, installed:

Carrier 24ABC660A003 Condenser (5 ton/16 SEER)

Carrier 58STA090-16120 Furnace (90,000 BTU)

Carrier CNPHP602YALAAAAA Coil (5 ton)

Supply plenum, filtered return plenum, emergency drain pan, float switch, concrete slab and 2 new return air ducts/grills/duct work.

Registered with Carrier to extend warranty to 10 years (vice 5 years) since installed by a carrier Dealer

During the install, repositioned attic units by flipping 180 degrees, installed 40 sqft plywood decking, cut/grilled/ducted 2 new 14"x14" returns, flushed the lines and relocated the exterior unit slightly to improve airflow. Also verified integrity/sealing of existing duct work and installed a Honeywell 4" filter.

Removed and hauled off a 12/13 SEER Comfortmaker 5 ton unit with furnace, plenums and damaged slab. Coil showed a clear leak (which started this whole thing) and furnace showed overheating/scorching on one interior baffle.

Total cost for the DFW area of North Texas, $7,480.

First cut at electrical usage looks to be about a 25-30% improvement and gas usage is mildly better too. Given the Comfortmaker was a 12/13 SEER model, this seems about right. Flow noise is down overall, which I attribute to improved return air flow and register exit velocity seems somewhat higher too.

I hope one of the experts with industry expertise comes to this thread. I'm wondering if the load calcs had fudge factors put in that influenced the results. 5 tons and a 90K furnace (even if 80%) seem too large for a 2200 sq ft house that's less than 20 years old.

A few errors, Elmer. The house is 1987 construction, and while it is a little above average in insulation and efficency, it definately needs 5 tonnes.

2202 square feet, single story, older, aluminium double pane windows, in Texas, with large south and west facing windows...calculated Manual J with in wall insulation assumptions (we just don't know) generates between 4.7 and 5.2 tonnes of cooling requirement. As a confirmation of this, my older unit was running just about flatout at an outside temperature of 108 to maintain an acceptable indoor temperature...this confirms the sizing, IMHO.

As for heat, the 80%, 90,000 BTU is slightly over requirements, but my installer was unable to get and install an 80,000 BTU version, and the surplus is not significant in my opinion.

That system is likely at best 14 to 14.5 SEER efficiency rating. You can pair a condenser rated at 16 SEER or whatever rating and if the furnace you attach it to isn't a higher end variable speed furnace you will drop off in efficiency. Other things that can effect efficiency further is size the equipment. This furnace has a multi tapped fixed speed PSC blower

Very common for 4 ton and 5 ton equipment to taper lower than actual rated efficiency of the equipment in question.

Very common problem with 58STA furnace is that either blower motor fails or the blower wheel comes apart or both at once, this can happen in as few as a couple of years time. It's rare for me to see this problem as result of a retro fit install and more common to see this kind of failure from new construction. The best way to limit or reduce exposure to this problem is properly sized return air not to mention proper sized duct system on supply end.

This equipment is probably at best some where around 53,000 to 57,000 BTU of cooling a full 5 ton capacity is 60,000 BTU's. Many manufactures in order to get efficiency numbers up reduce the rated BTU load the equipment is capable of handling at the larger side of the equipment spectrum. Square footage alone of a structure does not signify what the sizing of equipment that is needed should be.

Obviously it would be better more efficient if you could cut the load of the structure down so that it would only require 4 tons as opposed to 5 tons, but many times this is not achievable due to a host of various factors.

With that said in regards to sizing: If you took a picture of yourself would you on purpose take the picture so that your face is not shown / cut off from the view of the camera? So why would you ignore windows, placement of such, height of ceiling etc. from a heat load calc and only use square footage to 'assume' the sizing of HVAC equipment is correct?

1 months time of run time will not tell you much especially being this month temperature extremes are not extreme at all.

Thanks for the rain, Austin, it's been a bit dry up here till recently. I understand the efficiency issue, and the number you suggest don't surprise me. I considered the upgrade, but it didn't give me a solid cost benefit that I could find.

As for improving the structure, the problem there is cost too. With a $13,000 cost to replace all the windows with a much better version, it simply didn't make the cut when considering a electrical work and other work that had to be done when we moved in 6 years ago. Otherwise, retrofitting wall insulation is a crap shoot at best, and I've already grabbed all the low hanging fruit (LED blubs, AT rated cans, additional attic insulation, etc).

The equipment concern, useful to know, but with a 10 year warranty in place and properly upsized return air, I feel better. As for 14-14.5 SEER, doesn't really surprise me as I expect the previous unit was struggling to make 10 or 11 SEER.

I assume the comment about assuming sizing based upon sqft was directed at Elmer?

On the note about judging efficency thus far, I will politely disagree. I have a spreadsheet with monthly kWh usage, crosslinked with temperature data and annotated with energy efficency improvements over the last 6 years. I know I'm using 30-40% less power than my average neighbor in the same sized house.

I have the exact change in relative power demand for the last month versus pervious months/years and can adjust for temperature variables. Additionally, with the use of my intelligent theromstat and its time of day data on cooling and heating runs and the power use by time data available with my smart meter and the data from my electric power provider, all I am missing is detailed gas usage data. Now if ATMOS would just get jiggy with it...

Do you get the AHRI directory certificate for your system? I have tried to find it but so far I find no matches with your condenser and furnace.

No, I did not ask for nor recieve one. Trying to reference it myself, I don't find a match, with the coil generating the negative results. I have the individual data, but no system certification.

Low end Carrier Comfort series, both condenser and furnace..looks like a non matching system...price better than the equipment...definitely should have gone with Performance series furnace with high eff blower motor...

IMO

Well, tigerdunes, it would have been helpful to have said that when I asked about that issue in an earlier thread.

I solicited input on the initial Comfort system (Quote evaluation request) and got:

"You have been quoted a low end basic system. I would get an upgrade quote to the Performance series, both furnace and AC condenser." (tigerdunes)

I posted the new Performance upgrade quote and got basically only this response:

"I don't care for the Performance configuration since it has a 110K BTU furnace. It is a 80% efficiency furnace so the output is 88K BTU. That seems over sized for the Texas climate with a house of your size. I would expect a single speed furnace to short cycle on most winter days." (mike_home)

Then I posted a new thread (Comfort vs Performace) outlining the Comfort vs Performace and asking for input and got one response, with no real input.

Sorry if I'm a bit cheesed off at that comment, tigerdunes. Mike_home, thanks for your AHRI suggestion that I completely missed, that's my bad.

North Texan

you are totally off base... I looked up your thread way back from August-September. Take a look. Here was my post.

tigerdunes

I agree that you are undersized on return. How is your return air filtered? Furnace is attic installation? I would recommend a whole house filter media cabinet with easy access at the new furnace. You have been quoted a low end basic system. I would get an upgrade quote to the Performance series, both furnace and AC condenser. Is dealer installing new lineset or reusing old? New thermostat included? Just for info, Bryant is same as Carrier. Single speed vs two speed both furnace and AC is more about comfort than savings. Of course 2 speed condensers and two stage furnaces will cost more.

IMO

what more can I say. I tried to help you...

IMO

Just as an FYI, AHRI number doesn't necessarily mean the equipment will achieve the rated efficiency that number suggests. This number is merely a suggestion as to what THE EQUIPMENT SHOULD reach in terms of efficiency.

As an example: If you put a 5 Ton HVAC system in on a 4 ton capable return OR supply duct system this will be a drag on efficiency... no matter what efficiency rating you ultimately decide on.

If you put a 4 ton capable system on a 5 ton duct system, the result would be lower air pressure / velocity of air coming thru the duct which would limit performance in extreme heat / cooling loads.

These factors is why 'price paid' rarely dictate a good deal. You have to realize, that some HVAC companies... the only reason they exist is because they are cheaper price wise. That is the only reason they sell equipment, is because what they use is cheap too. There is much more to the argument than just discounts and such. If you were a company just offering a cheap price, what would your motivation be to choose better equipment? It's only about a cheap price... it's the only reason you sell something. There in lies the problem.

The devil is in the details. At least you named the thread properly... imagine how many people you may help from making the same mistake.

Ok, well:

tigerdunes, my comment was that AFTER that comment you offered no other input, even after I posted the Performance system. I greatly appreciated your initial input and I respect your knowledge and experience, but I heard nothing else after that from you. That was a shame, and a fact of life with free advice forums.

Austin, thanks for your responses. I agree on the details, and I forgot the AHRI matter. However, I’m still happy with my system and it’s function, which emphasizes the importance of the company/contractor in this equation. I am achieving the expected savings, corrected for temperature variables.

Mike, your input was valuable too, thanks.

while Austin is correct about the efficiencies listed on an AHRI matching number, the fact remains that I would not want a new system that was not an AHRI match. As to the new system purchased, I would be more concerned about whether it was a match and about the low end furnace over the nicer Performance series models. Condenser difference could be lack of pressure switches, poorer quality cabinet, and quiet factor.

IMO

Well speaking of the devil, I happen to run a furnace repair call yesterday customer complaint of a rumble coming from furnace area. Happens to be Carrier 58STA furnace. Needless to say, I took video of it so I'll post it to this thread once I get it edited and posted to my You Tube Channel AustinAirCo (< you can subscribe from that link)

Really the only thing odd about this particular call is that the furnace is 13 years old. Usually this problem happens much sooner in the life of this particular model of furnace.

Additionally what was said about efficiency earlier wasn't to suggest that this system isn't less efficient than your older system. It was just that it's not as efficient as it could be. In a round about way it is merely telling why the price was what it was.

It appears the installer corrected previous installation problems and you are satisfied with what you have purchased.. Those are the most important things. Hopefully you will get many years of service.

I would be curious to know why the installer picked this combination of components.

I would be curious to know why the installer picked this combination of components.

Simple, the only way he could get equipment price down under the Carrier name, make you think you are buying a 16 SEER when in fact you're not... and then make up for it in repairs a few years down the road.

That's the only reason I can think of. Then he may make some excuse that he's no longer selling Carrier products because of poor quality. Ah, the old shell game. He has to appear like the good guy, doesn't he?

If you don't recommend him to others because of this shell game, he's probably a dead HVAC contractor walking... which won't help you down the road when your system needs repairs.

Carrier makes several models in the Comfort line. One should be able to select similarly priced models that are an AHRI match. Whether the installer is able to get those models is the question. He could still be a good installer and trying to get the best value for his customers.

Austin, that's a pretty cynical take and completely off base here.

Company is a 31 year going family concern with plenty of business and very loyal customers. I discussed the Performance option with the owner, and came away with the decision to stick with the Comfort unit. As for price, compared to a couple of other quotes, he was below the others for the same basic equipment. Yep, three companies all proposed the basically the same stuff, three companies with good long records around here. The quotes on Carrier systems ranged from $13,000 (with a $4,000 rebate and a $500 discount from Oncor, making the bottom line $8,500) to $8,757 and $7,480. I was surprised at the compatibility for the equipment suggested between competing quotes. I'm also surprised at the AHRI incongruity between them, given that fact.

My intent was to go with the company I picked as long as they were within $500-1000 of the best quote from another good company. I've used their dad, and now them, since 1997, and I've had nothing but excellent results. The company has been a Carrier/Trane installer since before 1997.

Mike, thanks, I intend to get good use out of this system, as it's already meeting my expecations based upon my data. I'm mildly disapointed I didn't get an AHRI discussion, but I'll talk to my guy when he does my next checkup and see what he has to say then.

tigerdunes, again thanks for the early answers.

If this were me, I would get back in contact with the owner to express disappointment with receiving unmatched equipment and possibly being told misrepresented information about the SEER performance spec. See what the response is. If nothing else, they seem to have been less than fully honest and forthcoming with you.

Elmer, why?

The SEER rating for the outdoor unit is correct.

I fully understood that the SEER of any unit is impacted by the other factors in the system.

I did not ask for, nor was I quoted an AHRI matched system (my bad, perhaps)

Carrier's own website matches the two units, so why they never got AHRI tested/checked, who knows? Perhaps because they are the basic units, why spend the money for a certification no one knows about? It can't be inexpensive to check every combination, every year.

How were they dishonest?

I'm a bystander here with only the limited knowledge of a fellow homeowner who went through this process last year. But it seems you're a bit surprised that the outcome of your project may not be quite what you expected or had in mind. And different, either because of what they told you or didn't tell you? Maybe I'm wrong.

Were the other bids you got for matched pieces?

Cynical? I thought I was being fair, given my experience and what I see in the field. Why a company would match / put a system together that won't reach the SEER rating of the condenser, why not just put in a 14 SEER condenser?

You do realize you pay more for the 16 SEER condenser and the extra efficiency is just wasted, Right?

If this company has been Carrier / Trane dealer since 1997... they know about the problems with this particular brand of furnace. How could they not know? It's like willingly selling someone a lemon. Call it whatever you want, this is my opinion. I wouldn't sell something that I know for certain has a defect. I've never had to replace blower wheels on any other brand in over 23 years of running HVAC service (Katy, Tx).

There was a company outside of Dallas / Ft worth area that expanded to Houston not more than about 5 years ago. In business for 54 years, until they went bankrupt Jan 2, 2013. Avery Air Bankruptcy --- fortunes change like the wind in this industry no one big or small is immune to it.

What other reason other than those I provided would they put together a system that is an odd ball, unmatched system as best as we can determine from a forum board?

This would be completely acceptable and understandable if this was a retro fit repair and not a complete system change out.

Vith, thanks for the input.

Elmer, I'm disappointed at the comments directed AFTER the fact that weren't offered before, when the same data was available. The other bids were same line and/or identical components

Austin, your experience is your experience. The fact you don't like the 58STA/STX furnaces is fine, but to call them defective when a search shows no such trend is a big reach. Yes, companies have trouble, but to lump any company into that bowl without me naming them is a cheapshot. The system is, according to Carrier, a matched system.

I posted this for people to get some feedback on a previous post, not argue about this, I consider this topic closed.

North Texan, to say that I don't like the Carrier 58STA/STX furnace would be like saying I hate working and making money. So, no never said that. LOL, good one though.

Defective versus normal breakdown is typically in the eyes of the HVAC contractor. You have to realize what is a normal breakdown and what isn't. People repairing their furnace are going to think it's a normal problem, that every brand suffers from -from one degree to another.

Realize "blower wheels" are not a normal failing part. Carrier is the only brand with this problem, possibly Bryant to... but I've only seen it on Carrier 58STA model furnaces (every size, although the 5 ton model I tend to see it most often).

Blower motors fail on every brand, blower wheels do not. Other than Carrier brand equipment, I have not once replaced a blower wheel on any other brand...in 23 years of running HVAC service calls and that includes pulling crap out of them in which they sucked stuff into them because there was no filter in place.

What I am talking about here is experience and that I prefer to sleep well at night with a clear conscience when I know better from my repair experience.

This doesn't mean I am immune to selling equipment that doesn't fail for one reason or the other. But my equipment failure rates - equipment that I install myself is very low. Tight range from 1-3% every year. What is considered normal in this industry is 25% failure rate. You know so you have something to compare to.

That means for every piece of equipment I put in (regardless of brand - I've used 8 different brands over the years) there is less than 3 that suffer failure out of 100 pieces - inside the manufacture warranty envelope.

This particular failure on Carrier 58STA can occur at any time, I've seen it happen as soon as year 3 however most common is between years 5 and 8 years old.

Without further ado, I embed the recent Carrier furnace repair video to this thread. Model #58STA

Bottom line is you appear to be very happy with your new system. Congratulations!