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|
|Resistant to Corrosion||No||Yes||No|
|Durability||Durable||Probably Durable||Less durable|
|Repair Difficulty||Easy||Extremely hard||It depends where leaks|
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.
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.