Update 2023: This is an aged post from 5 years ago. Traditionally, AC coils were predominantly made from copper. In more recent years, many manufacturers (include big brands like Trane, Lennox, Carrier or Goodman) have shifted towards using aluminum coils.
Here is how the copper coil and aluminum coil look like:
Most manufacturers are starting to switch from using copper coils to aluminum alternative as condenser and evaporator coils for a number of reasons. Before you decide to purchase a new system with either copper or aluminum coils systems, it is good to have some knowledge of what you are setting yourself up for.
By tradition, copper is considered the better choice when it comes to the manufacture of evaporator and condenser coils. The reason behind this is its rate of heat transfer, its cost effectiveness, its flexibility and of course, the fact that copper line sets were made to join split systems. The cost of copper has however skyrocketed over the past few years, thus turning the tables in the manufacturing industry. Manufacturers are now looking into aluminum because it is cheaper and also boasts a number of the benefits that have been mentioned above for copper. The main difference is that Copper has about two times the conductivity that aluminum has when it comes to heat transfer.
Copper VS Aluminum Coils Simplified:
| Copper Tube & Fins | Aluminium Tube & Fins | Copper Tube & Aluminium Fins | |
| Cost | High | Low | Mid |
| Efficiency | High | Mid | Mid |
| Resistant to Corrosion | No | Yes | No |
| Durability | Durable | Probably Durable | Less durable |
| Repair Difficulty | Easy | Extremely hard | It depends where leaks |
Repair Difficulty
It is easy to repair all copper coils if damaged in the field whereas with aluminum, once damaged, it will require an entire coil alteration. Today’s copper tube and aluminum fin coils are not very repairable either. The copper is so thin that it is very difficult to braze.
Resistant to Corrosion
Aluminum is resistant to corrosion. An HVAC tech forum participant says, “Aluminum coils have oxidation protection that copper does not have. Heat transfer is lower, but they increase the surface area to compensate. I have been a fan of aluminum coils for 30 years, never had any spontaneous leaks. The big issue with aluminum coils is, IF a leak occurs, repairs are nigh impossible.”
HVAC professional Gary Edelman also agrees and says, “The jury is out on aluminum coils. I’ve had a few leaks over the last 8 years or so since I’ve been using them but not a lot. How they are going to hold up long term like 15 or 20 years we’ll just have to wait & see. The jury is not out on copper coils. They all seem to leak no matter what brand & I would not install a residential unit with a copper coil.”
Bad Trend for Copper (skimp)
Modern technology coupled with the cost of copper has forced manufacturers to skimp on the material. The import here is that thinner(and less efficient) coils have flooded the market. There is the perception that copper lasts longer than aluminum. This, however, might soon change due to the aforementioned scenario where manufacturers are using thinner and less stable strands.
Besides, the price of copper makes it more appealing to thieves. It is being targeted and sold later at a cheaper price in the market. If you use the material, ensures that the wires are well secured and this will discourage theft.
Be Wary of Hybrid
While copper is used for line sets, fins are used for aluminum. When copper and aluminum are joined, mostly galvanic corrosion happens. Galvanic corrosion usually happens when two different metals are connected. With modern technology and great advancements, the concepts of joining unrelated metals have made aluminum an appealing choice for some.
Conclusion
Each metal has its own advantages that make it a suitable choice for evaporators and condensers. The downsides are also split evenly, so the aspect of choice really falls to the consumer. Looking at both the pros and cons of copper and aluminum, both coils are used according to the availability of space, the cost-benefit when doing the installation as well as the maintenance. There is some equipment that will work well with aluminum and some that will best work with copper.
By the way, my personal priority is All Copper (no skimp) > All Aluminum > Copper Coil + Aluminum Fins> All Copper (skimp). Only personal. If you have any questions and suggestion for this article, just drop a message below.
You mentioned your preference is for non-skimp all copper coil/fins, but you do not mention which manufacturers make such units. Can you tell us?
Galvanic action should sacrifice aluminum when bonded to Copper. All copper (no skimp) is my choice.
My a/c was installed 3 yeays ago and no cool found indoor coil(Cu)leaked.
The installer told me new Freon(R410a)corroded copper than R22.
Is it true? Can my indoor coil repair without a new one install ?
If alumimium one install, the cooling efficiency is about a half than copper?
I’d like to know such companies who make units with all copper coil no skimp…
When did they switch from copper to aluminum coils in A/C evaporator so and condensers. What year??
We have a 1 year old Trane central air unit. It does not work because it lost all of its Freon due to a pin point hole in the aluminum coil. We have a dog that has urinated on it several times and the company that installed it said that the hole was from the urine. Really?? We’ve been looking on line to see if that can happen. We do not want to have to pay for repairs or a new unit that could be a manufacturer’s defect. What do you think?
That is true. I have a house with copper coils and aluminum fins. Previous owner had a dog that urinated on the lower corner of the unit and all the aluminum has rotted away in that spot. Fortunately the coil is copper. No leaks.
Good article- Need to replace a 5 ton 30 year old Lennox. Is there any unit today that uses all copper condensors and evaporators. We have extreme allergies and sensitivities to smells so would like the copper for that reason especially.Thanks
Will aluminum coils last longer when animal odors are around? Is it more resistant to pet odor?
A/C installers are getting like used car salesmen. I asked several about aluminum vs copper cooling coils. I’m told the aluminum is needed as it is needed to handle the higher pressures of R410 while these same people say they will use the same copper line from compressor to A frame that has aluminum cooling coils.
Anyone know who makes an A-frame with cooper tubing?
ADPcoil makes COPPER evaporator
A tech told me that older exclusively aluminum AC units often lasted 25 years or more while copper units have a much shorter life expectancy. We have an all aluminum unit which is still working well although it is 30 years old. Comments?
Your 30-old A/C was made back when A/C’s were ROBUST and used electomechanical controls. No doubt the aluminum was of much better quality back then as well.
The tech you spoke of was thinking of the common copper tube / aluminum fin hybrids and those two metals don’t get along. I marvel that they were even permitted to be built because of electrolysis!
Thanks to globalisation and attacks against consumer protection over the past 18 years, the new AC’s are just terribly inferior. Keep your vintage A/C working as long as you can or until the cost of R22 forces you to replace it. Keep the air handler clean and free of mold and keep the outside unit cleaned out as well.
The primary problem with all aluminum coils is once again, installation. While most of the coil is indeed aluminum, some transitional tubing relating to the metering device (TX(E)V/EX(E)V/Piston) will still be copper. During the manufacturing process, and the installation process, these short sections of copper tubing may come into contact with aluminum surfaces, causing corrosion over time followed by non-repairable leaks in the aluminum. Depending on the quality of the manufacturer, these copper segments may be insulated with foam tape, rubber/heat shrink material, and the coil often comes with extensive warning labels and documents removing liability from the manufacturer. It is my experience that an all aluminum coil, carefully installed without abuse, installed with proper brazing and vacuum processes, has the longest possible life expectancy. On rare occasions, after extensive dirt and mold infiltration that prevents condensation drainage or high humidity areas, the sheet metal portions of the coil will corrode into the aluminum pressurized portions, however this usually requires extensive, obvious abuse or neglect on the part of the homeowner. Aluminum fin/Copper is almost the only other option in Central Kentucky, excluding unique proprietary designs such as the Spine-Fin Trane coils or the Micro-Channel coils (primary failures being thin materials and copper-aluminum corrosion again). In 10 years in the trade, I’ve never personally seen a copper-fin residential coil, excluding hydronic applications.
We installed a new Goodman 14 seer AC/ heat pump system in 2012. In 2017 the inside unit needed the all aluminum coil replaced due to leaks. In 5/2021 we had to have the outside aluminum coil and compressor replaced due to leaks. Today the service tech advised the inside aluminum coil is leaking along the fins on both sides of the coil and needs to be replaced again. The replacements have so far been under Goodman’s 10 year warranty but I’m still out the cost of labor and Freon. So from my experience the aluminum system components being made today are garbage, as both inside aluminum coils only lasted 4-5 years, and the outside components 9 years. I advise anyone getting a new system to be sure the warranty is registered with the manufacturer, because your going to need it.