Our family has walked into Costco twice and set up appointments and waited for representatives to come and they never showed up. I guess they dont need money or want to work. They never even called to let us know they werent coming. Very unprofessional. I dont know why Costco lets this happen. Duarte Ca

It's really not up to Costco, it's up to the HVAC contractor who serves the store you visited. That's why 3rd party services rarely live up to anything good.

$20000+ is what I got from Costco for a 4T unit...

Got mine from Costco, works great. Company was wonderful.

There's no more expensive way to contract for HVAC than through a retailer. You're paying 20+% too much or more. The money for the gift card isn't a discount on the price, it's the excessive margin being returned in part to you.

Call a few HVAC contractors with reasonable Yelp ratings. Ask friends. You'll get more for less.

Edit - Oh my, another old bumped thread. I regret my comment but will leave it for whomever may wander by.

I live in Atlanta and just had the “Gold” system installed. After checking out my old system the salesman told me that I needed a 4 ton, my old one at 3.5. Tons wasn’t enough. I know he was right because my old one ran 24 hours a day in the summer even after being serviced and properly charged.

I have 3 systems at my home. We had a Carrier system installed 5 years ago and it has had a lot of problems.

Cool-Air handles sales and installation in Atlanta. The salesman was very knowledgeable, took his time. The installers showed up on time, they were very polite, there were 3 workers and they all knew what they were doing so they were in and out in a little over 3 hours. They did a nice, neat, good looking job of installation and tested the system. I’m picky and I couldn’t find anything I didn’t like. They cleaned up fairly well.

As part of my deal I get 2 services on the new unit and they tossed in 2 free on the Carrier system. They also enlarged the intake in the upstairs (the new unit is in the attic). The cost after all rebates and promotions was $10,150. I also get $658 back from my home warranty company. If this system works, I’ll be extremely happy with the job. I may have paid a little more than if I had had another company do it but sometimes you get what you pay for. Costco makes their contractors get permits so my unit will get inspected by the city next week. I had 3 other estimates done and I was afraid to use any of them because the people they sent out barely looked at my old system and gave poorly written estimates.

These systems are all not made as well as they used to be. They are engineered to last 10 years if you are lucky. Makes no difference whether it’s Carrier or Lennox. I think it’s important to get your system serviced twice each year.

I used Costco here in Toronto, because I did not want to get "taken advantage" of by a local company. I'm a Costco member, I trusted them. In the end I feel I still got shafted, way over priced. The $600 dollar gift card was just my money that I was now forced to spend at Costco. The year before after my annual service I was told my unit needed replacing ( which was true) I was quoted a way better price. At the time I though it was just a sales tactic. I regret not taking that deal.

Live and learn...purchasing HVAC through a big box store is a losing proposition...sorry for your trouble...out of the so called Big 3 brands, I would say Lennox is a distant #3, maybe not that high...

TD

It's not just Costco (or Tudi). The majority of HVAC companies gouge their customers like this. The going rate for replacement of an evaporator coil is $1000 (labor) for 3-4 hours work so replacing a compressor is going to be more than that. It's a sad commentary on what is now a predominantly crooked profession.

And please, anyone who doesn't like this post, no whining about "overhead", "training". "parts on the truck", etc, etc, etc. It just doesn't wash!

SKTN is absolutely correct. I replaced TRANE Evap coil (out of warranty) last June for around $2500 and that included a real leak test and a patch until new coil could be secured...a new compressor about the same...

TD

Well let me add my experience with Lennox.

2004 I purchased a Hvac top of the line Variable speed AC unit with new duck work complete price on 10k. Lasted ten years until a problem occurred that would have cost 2k to repair. I installed a new Lennox 9k price, again their top of the line elite series.

Well almost 3 years in and failure, coils developed holes leaked freon. Outage of a few days with $300 repair bill. Come to find out there is a class action suit against Lennox for the coils, but the suit closed out. Lennox never notified everyone of the problem. I did obtain replacement coils due to my awesome AC company. However another $680 in labor to install. Contact made with Lennox resulted in a "go pound salt answer" when I requested help with the almost 1k out of pocket expense, for a problem they knew about all along. Not to mention the details of the class action required a owner to foot the bill for two coil replacements prior to replacement. And only then $550 for labor would be reimbursed. That would be nearly 4k out of pocket before new improved coils would be provided (that is where my awesome AC company saved me).

End result I believe that in this case Lennox failed to stand behind their product. I will not be buying Lennox again. It may have been acceptable if Lennox did not know about defective coils but that was not the case here. Hope this helps with people looking for AC units (especially at the higher price unit by Lennox).

COSTCO has a warranty department. If a product passes their standards, I would do it. Google on COSTCO warranty and how they require products to go through testing. We have had 100% positive success with ANY item we returned or questioned their warranty.

Costco offers a second year of warranty on some items. The 2 year warranty is described below. I am confident HVAC systems are excluded. HVAC comes with at least 5 years and most often a 10 year parts warranty. Best case Costco may cover the labor during the second year. You should call Costco to verify this coverage.

I could be wrong, but I don't think Costco tests anything. The second year is a promotion funded by their memberships.

Costco Concierge Services

2 YEAR WARRANTY

Costco extends the manufacturer's warranty on Televisions, Tuner-Free Displays, Projectors, Computers* and Major Appliances† to 2 years from the date of purchase. See the manufacturer's warranty for specific coverage terms.
For warranty service, contact Costco Concierge Services at
TOLL-FREE 1-866-861-0450.
Available 5 a.m. - 10 p.m. (PST), 7 days a week, excluding holidays.

To learn more about Costco Concierge Services, Click Here.

*Excluding Touchscreen Tablets.
†Refrigerators (above 10 cu. ft), freezers, ranges, cooktops, over-the-range microwaves, dishwashers, washers and dryers.

BEWARE, do not buy a COSTCO HVAC, we got a lemon from Costco, the subcontractor failed to install it correctly and the system keeps on breaking. I’ve contacted Costco repeatedly but they point to the subcontractor and the Sub focuses on denying service. Lennox has such a poor attitude and do not address the issue at hand (the failed installation). I paid an independent Contractor and leaned how the Sub did a lousy job. Apparently Costco gets commission for getting the Sub the customer and then they wash their hands. Beware !

Lennox is absolutely the worst company to deal with. We purchased a new furnace and a/c system through Costco two years ago. They failed to replace a condenser pump (saved themselves $100) and it failed sometime this year. Lennox claims they didn't quote on the pump. WTF! It was a complete system replacement. Now I've got standing water in the crawl space and mould which will have to be remediated. Costco says they won't do anything about it. $13500.00 for a defective system.

Don’t get a Lennox. We bought through Costco, brand new AC and Heating unit and it died within 4 years. The coils completely melted down. The installer said the part is covered under warranty but of course not the labor. The part is $500, the labor is $5000!!! Then I found out there was a class action lawsuit against Lennox for faulty coils. I reached out to Costco but the rep you have to go through is a Lennox rep so I got 2 emails and then crickets. Costco and Lennox are totally is complicit in scamming its customers.

my wakeup experience was with Home Depot, when my HVAC needed replacement.

I knew that I needed a 4 ton split system to replace a "closet" system, pushing the compressor to the attic and giving me the closet.

They wouldn't discuss what systems cost over the phone, as they "couldn't know" what I would need.

They didn't send a tech out to my house, but a slimy closer. It took him something like 30 seconds to turn to the four ton split laminated page and begin the hard sell . . .

(a few years later, when I described this to a former Home Depot person from that area, he was downright *livid* over it . . .)

Anyway, I ended up going with the *only* company that would discuss prices for a specific configuration over the phone without ending their own closed . . . which turned out to be a problem. Unfortunately, I was too overloaded and stressed at the time to deal with the contractors board to clean it up.

But, yes, multiple;tiple quotes from different types of companies.

(We had another one a year or two ago when I badly needed my sewer line jetted. One company sent out wanted about $3500 for significant repiping . . . .and it turned out that removing two hex screws on the "bandage" on the cleaning port let me remove the obstruction, and let a normal eating do it . . . )

Costco had there contractor come out Last week for a Quote. They are a well known contractor in our area. I thought the quote was high but I didn’t know what to expect. Thru Costco it would cost $11,135. I got two other quotes for the same equipment and they were $8,776 and $8,699. That’s a big difference. Even if you subtract the 17 percent that Costco was giving back in a Costco card they were still several hundred higher. Looks like the price is higher to cover the 17 percent. Probably if I contacted that contractor myself they would have been more competitive. My other two quotes were big contractors not fly by night. The other thing is once you go thru Costco the contractor cannot do anything for you except Lennox thru Costco. Even if they have other options. It was easy to see it wasn’t a good deal. I am waiting for another quote this week before deciding. Cost you nothing so get plenty of quotes and check for Better Business Bureau for complaints.

More important than the BBB may be the state contractors' board, or whatever its called in your state.

The BBB doesn't mean much as the BBB many times gets involved in "Conflicts of Interest" for $$$.

If you got money... well the BBB can make bad marks disappear. The same goes for Yelp and many of these other kinds of "advertisements" for $$$.

Money always wins in the end. Think long and hard on why that is.

A company isn't going to pay for an advertisement to someone that is displaying their bad marks.

wou you please let me know h long ago you got this price quote from Costco? I live in Southern California, Burbank. I recently got Cos pricing which was $25,000 which was higher than any other places I got the bid.

I got mine in January 2021. My quote was over $11,000 with 17 percent back on a Costco card. When I subtracted the card from the price and compared to my other two quotes it was still several hundred higher. Not a good deal going thru Costco. My other comment I said Costco had 3 contractors come out. Only 1 for Costco the other 2 I had called

HVAC prices have skyrocketed over the last 10 years. It's a combination of manufacturers preventing their products being sold in the free market (nowadays read internet). and installation companies taking advantage of this by jacking up prices - where else do you find $400-$600 hourly rates for semi-skilled labor?

I live in the OC. I just got a quote from the Costco contractor today, 18K after the discounts. Did not include new ducts. And that was for the #3 system. The top one was over $25K

COSTCO LENNOX HVAC Inner coil MELTS DOWN after 4 years!!! Piece of junk don’t get it!!!!! Parts will be covered under warranty if you have kept up with servicing units BUT the labor will not, an it’ll cost an additional $5k with no guarantee that’ll not melt down again. Get a carrier brand unit instead.

Well, that's a little over the top(?) All copper evaporator coils have had problems over the last 10 years - that's why manufacturers have switched to aluminum (including Carrier). And it costs around $1000-$1500 in labor to replace a coil (assuming part covered by warranty)..

Started with Costco for a bid. Thought it was a good bid, you know Costco value...until I started receiving other bids. They were way out of the ballpark for inferior units. Research Lennox. They receive horrible reviews. My advice is if you have the opportunity to research bids, call companies and look at online reviews. Don't use a third party they will just jack the price up. I went with a Carrier unit with a local, reputable company.

Research Carrier...

Carrier Reviews Link

There's this common theme among those who think they have been wronged by some AC manufacturer that they can just jump to another manufacturer and all will be well.

If I was going to name this syndrome it would be something along the lines of "the grass is greener in the other yard across the street".

There is no perfect AC manufacturer. They all break. My job depends on them to break... the difference among manufacturers reviews is their ability to filter the bad ones from the good ones.

Many of the parts that one manufacturer uses to assemble an air conditioner? You think another manufacturer isn't going to select those same parts to make their unit?

Those parts are either made in China or Mexico or some other cheap labor country.

I don't know who you are but I can tell you they are coming for your freon money. But they aren't going to stop there. I can find those poor reviews, I will not stop until I find them. I have attained a unique set of skills, skills that I have acquired over a very long HVAC career.

funny clip -- you may not think it's funny, but it's also factual. (fast forward to 31 min 55 secs to see the funny clip)

I recently purchased the Lennox unit from Costco and it is not a good deal and also buyer beware.

I was looking to have a 3-ton mini-split unit installed in my garage. One of my requirements was an external smart thermostat. Costco does not do the install and is a middle man. They sub contract the work out to my local HVAC contractor who said the unit would support an external smart thermostat of my choice. This was confirmed 3 times. After the install was completed, they were unable to support an external smart thermostat (not Lennox). I am now in a battle to get the unit removed and refunded and Costco is a total pain in the ass and refused to refund me even though the contract specifically states install customer provided smart thermostat. I'm working through other channels right now before suing them for the refund.

Couple of lessons learned:

1. Lennox is dated and doesn't support external smart thermostats. This is important so you can control all your HVAC through a single app and also gives you added features from a tech company.

2. The "deal" itself is not a deal. After getting quotes for a new unit (that does support an external thermostat), I found that you are getting ripped off. Costco gives you a 10% rebate to buy stuff from Costco but even after all of that you can get units installed cheaper from others

3. Go buy a Mitsubishi or Fujitsu unit as they are more current with features and support of things. Everyone has been telling me that Lennox is the lowest end brand/units

4. Do not buy any contractor services from Costco because #1, they don't do the work and it's hard to get a refund if anything goes wrong. They are just a middle man taking a cut that you can get better pricing elsewhere.

Wow, I should have read these reviews prior to committing to Costco for a new HVAC system. I had a couple of quotes from local HVAC contractors that were cheaper than Costco/Lennox with Sierra Pacific Home & Comfort ( Sacramento) but decided on the Costco route because of the incentives. What a mistake and I after much back and forth with Sierra Pacific I got the contract cancelled and will use my local installer. Sierra Pacific was very uncoordinated and once the job was sold the salesman was MIA for any follow up questions and concerns. We are faithful Costco shoppers but would not go down this road again with them for any 3rd party service. Best to go straight to the source for what your trying to do.

Sometimes going through a big box store works out well. Many times it doesn't!

You can also buy direct and have a pro install it. Save MILLIONS!

Where To Purchase HVAC Equipment Online As A DIY 'er Or Homeowner

https://www.youtube.com/watch?v=165PCWC06XQ

Stop Getting Ripped Off By HVAC Companies. Replace Your Gas Furnace Yourself

https://www.youtube.com/watch?v=4iQZnT7Ouck

I went through Costco and it has been a nightmare. The installation contractor did a terrible job and neither Costco nor Lennox will hold them reaponsible to fix the install. If I could do it again, I’d get recommendations from friends and find HVAC comapnies in my area with good reviews.

Well, you paid Costco for the install, so it's Costco's problem. Don't let then BS you, insist they make it right!

I'm shopping for an HVAC for a rental unit. The Costco vendor insisted on meeting with me instead of the property manager. Vendors usually do this because they plan on applying pressure to have the contract signed on the spot. Obtained quotes from two other vendors before contacting the Costco vendor. The first two quotes were for $9000 and $10,000. The Costco vendor quoted over $29,000. I thought it was a joke. I'm not paying triple the price for an HVAC unit just so I can get a Costco Shop card.

Ihave the Costco deal. warranty is the main issue with Costco i got a great warranty and great service I probably paid more, but it been good. it it’s a high end system and lowered my electric bill a lot. I’m glad i did it. you can get a unit got less, but maybe not over the long hual. if price is your only prio, buy a Goodman If warranty and efficiency is, consider the Costco deal

Spent $25K on a new Lennox high efficiency gas forced air furnace and a central air conditioner Neither one worked well to either heat or cool my home Now I am told by the installer/serviceman that my evaporator coil is bad in the AC system and needs to be replaced at a cost of $4,000 Just discovered that Lennox had a class action against over the Model CX-34 evaporator coil---the same crappy model I got

"my evaporator coil is bad in the AC system and needs to be replaced at a cost of $4,000"

That's an expensive replacement part (I take it your 10 year parts warranty has expired) but that price seems a little high. I would think $1500-$2000 for the coil and $1000 installation.

It took ten years, but someone finally reported good service from Costco!

[put one of those little yellow guys rolling around laughing his head off here]

My compressor developed a leak, at something like 15 years old. My guy, an independent was able to replace it and the coil for somethuing like $3500 in parts (or as it $4500?). That is, he swapped the guts out of the old housings, for a lot less than a new system.

Any system 15+ years old probably needs to be replaced. They lose effiency and even though they still run cost a lot of energy to be lost But replacing a coil is not uncommon at 10+ years. i good repair person will offer repair and discuss the advantages of system replacement. Many of the coils are made of aluminum now and so they corrode easier than copper. Cheaper is not always better than quality.

if price is your only prio, buy a Goodman If warranty and efficiency is, consider the Costco deal

Goodman makes premium models that can rival any other brand on the market today.

The cost for Goodman, along with all other brands has gone up in price since 2021.

Brands are a very small part of what kind of "deal of the century" you're trying to get for your home comfort solution.

If brand is your only consideration, 75% of you are going to be disappointed. Buy a system for what it does & how it does it and what problems it solves without causing new problems. You won't find this kind of info on the side of a shiny metal box in the form of a name.

This Goodman in the video below lasted 24 years in a hot climate. Definition of a hot climate: requires cooling 10 months of the year. The average life for this climate? (Katy, Tx) around 12 years most of the time.

The Goodman in this video lasted double this amount of time. The proof is in the video:

"Hard to STOP?? A Goodman"

So far (since 2019) It's even harder to stop a BOSCH. Not for the name, but what it does and how it does it.

I service the Katy, Texas area.

When I needed a new furnace it was January in Pennsylvania and my furnace died. No heat at all in January during Covid.

I had Home Depot come out and had one of our larger local HVAC companies come out, then I called my home insurance company and asked the receptionist who she would recommend calling. She gave me another person to call and his quote was about 30% less than the other two. When I read reviews online for the systems each offered the reviews were better for the system he was recommending than either of the other two. I don't remember what the other two brands were, but I ended up with a Rheem furnace and AC. I have not had any issues since and used the same guy to put in my hot water heater and to run a gas line for my new gas range. I found my guy. Honest and fair and his employees are the same year in year out, which tells me he is a good boss as well.

I also have the rider on my State Farm policy that covers home systems. It doesn't work like a home warrantee. If your system is x number of years old it pays x dollars toward replacement of a failed unit. It runs $25.00 a year. My tankless hot water heater, furnace and dishwasher all went out within a month of each other in the first year I had the rider. All of these went out within a few months of each other and in my first year with the rider. Everything in the home I purchased was at least 17 years old, so they were bound to go. The policy gave me something toward the replacement for everything except my AC unit. It wasn't dead, but was not compatible with the Furnace. I don't remember the exact amount that I got through my insurance rider, but I think it was around $1600.00. Not a ton of money, but it will be a long time till my $25 a year reaches the break even point.

"Many of the coils are made of aluminum now and so they corrode easier than copper."

Not necessarily. The reason most manufacturers moved to aluminum coils over the last 5-10 years is less corrosion than copper! The quality of copper (most likely due to contaminants in recycled copper) had become so bad that AC coils were failing by the hundreds of thousands due to formicary corrosion. Just looks at all the class action lawsuits against manufacturers of copper coils!

"Many of the coils are made of aluminum now and so they corrode easier than copper."

Not necessarily. The reason most manufacturers moved to aluminum coils over the last 5-10 years is less corrosion than copper!

Not necessarily again? Much of it has to do with the thickness of the tubing wall of coils in question. In addition to that the cost of refrigerant(s) all kinds have dramatically gone up in cost so there is more attention given to an AC system OR Heat Pump that is leaking refrigerant.

Refrigerant leaks have always been a problem: Yes. My entire 30+ year HVAC career. This problem will live on beyond my career? Yes.

It's not uncommon: meaning that I often see in person newish aluminum coils that have failed every year that are much younger than a copper coil failure of the past. Worse offenders are in the range of 1-3 years old. A little more common is 5 to 6 years... even more common: 8 years Rare: and aluminum coil that is over 10 years old. (each piece of equipment is stamped with a date code when it was manufactured this is how I know -- first hand knowledge (not what someone is just repeating from the internet)

Brand doesn't matter to the extent that some think.

Galvanic corrosion is more likely the demise or reason if you will why all aluminum coils fail.

Probably one of my most watched video explaining this is more about copper coils and reasons why but I also talk about why aluminum coils will fail just as much or more than copper will.

Since Efficiency requirements keep going up, coils keep getting larger and larger. The bigger a coil is (for efficiency reasons) requires more material to make the coil. The cost of those materials. The weight of the overall product. Copper is heavier than aluminum and costs more.

The bigger the size of the equipment goes, the less equipment can fit on a truck so the cost to ship it become greater. All these factors come into play, the picture is much larger than most care to think about.

What is galvanic corrosion in simple terms?Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water.

That water in an AC system is condensate water. There isn't a way to escape failure of a leaky evaporator coil. This is all myths and old wives tales.

Copper Vs Aluminum Coils video:

I service the Katy, Texas area.

I don’t think I said that’s why they changed, but I actually figured it was bc aluminum is much less expensive than copperT, but thin copper would likely leak before ghick aluminum. One would also think copper would be more thermally efficient

joepiccaso53, I think the primary reason is cost, I haven't seen any literature to suggest that aluminum is any more efficient than that of a copper coil: like specifying exactly the difference in efficiency from Coil A that is copper versus Coil B that is aluminum and that is the only difference from one coil to another.

I do have literature that says just configuration of the equipment can have a mild impact on efficiency. But only mild meaning like 1% more or less efficient than some other configuration. So not enough to make it ecconomically viable to only do it one specific way. Like vertical only installs vs horizontal only.

I have had plans to revisit and remake that video to show further what I believe to be the problem as I have cut the ends of the coils to reveal the tubes that have an uneven surface roughed up if you will with what looks like to be the edge of a file on the inside of the tubes that run thru the evaporator coil. So with all these peaks and valleys inside the tube of the coil the part that seals the tube in a multitude of places is very thin amount of metal. From that perspective it's not hard to imagine where the leaks are forming when the coil indicates leaks inside the fin pack area of the coil and not at the ends of the coil where they are typically chemically sealed in the case of all aluminum coils.

This (the roughed up inner tube area) is essentially I believe to create more surface area, causes the refrigerant to tumble thru the coil absorbing more heat from return air blowing across said Evap coil. They were doing this sort of thing with copper coils prior to switching to aluminum.

What difference does it make if failure is a given anyway? I mean you can argue copper failed incredibly easy and copper costs more etc.

If the coil has a leak it's not going to operate efficiently anyway. Also they used aluminum back in the 80's for evaporator coils I just don't have any video to show that. Often the failure with those was the connection point from aluminum to copper was merely a compression type connection which would fail and no good way to fix it (meaning it wouldn't leak refrigerant) -- refrigerant was much cheaper then like incredibly cheap.

The technology to meld the two metals together copper line set to all aluminum coil is leaps and bounds better than the 1980's variety, but the aluminum coils just fail elsewhere.

If I had discovered some coil or some method to avoid failure wouldn't that be something to hang your hat on?

If you look to that video I posted: I literally show you that aluminum coil failed all along the bottom of that coil. It's an upflow coil. Meaning the condensate waste water it creates is all along the bottom of that coil.

Why are these clues important? I believe they show why there is failure and why there will always be failure. That condensate water the coil creates is what is doing it at least in this particular example. Refrigerant leaks can happen due to other reasons besides as I also demonstrated in the video.

Well, It isn't too hard to show that copper is may more efficient as a conductive metal. I'm sure there are things that they do in the design and the manufacturing process to help aluminum to be a more efficient heat transfer. But, follow the money, and that's not always a bad thing!

I'm sure there are things that they do in the design and the manufacturing process to help aluminum to be a more efficient heat transfer.

joepiccaso53, Yes and no.

In terms of Evaporator coils they are made essentially the same as copper coils were before. When the switch happened roughly 10 - 11 years ago, I was more heavily into warranty replacement coils. I could bore you with untold stories of swapping copper coils with an aluminum replacement coil of same heigth, length, width / depth. Would you not argue that is the same coil, just all aluminum?

Today if you compare an aluminum coil to an older copper coil the dimensions have changed! But this was due to changes in efficiency requirements that would have also impacted the copper coil as well. (if the copper coils were still being made to the extent that aluminum coils are made now?)

The efficiency requirements never go away, just because MFG's are using different materials. So when the switch from copper to aluminum took form 10-11 years ago the efficiency requirements to that were in force to a lesser degree.

In 2006 AC efficiency standards were raised to 13 SEER. (Seasonal Energy Efficiency Ratio).

In 2014 the efficiency standards increased again to 14 SEER in the south and southwest as the DOE split the map into 3 different sets of requirements for efficiency. (If the equipment in question was heat pump or package system the requirement was 14 SEER across the board)

This efficiency change did little to the design of evap coils. Remember I told you I was involved then with a lot of copper coil failures and the warranty requirements of major MFG's then was much easier process than it has been since about 5 years ago.

The efficiency requirements of 2023 changed things yet again as they (DOE) got this clever idea to rework the formula of SEER calculation and rename it SEER2. This has nothing to do with the "metals" change of the manufacturers as by this time they had been using "all aluminum" coils for around 10 years by then.

Conductivity: both metals are used in electrical connections. In terms of heat dissipation, yes both metals are used for that as well.

To argue that one is less or more would require a scientific test done in a lab, not jecture from the internet as to what one or a few people think / believe to be true. If MFG's have to hit efficiency targets these targets are determined by actual tests, not conjecture from the internet.

If 10 years ago, I had replaced an all aluminum coil for a defective leaky copper coil and there were some performance issue due to the inability of the aluminum coil to transfer heat like the previous copper coil? Full well knowing that my climate is hot and sticky upwards of 10 months of the year?

I service the Katy, Texas area.