Aluminum VS. Copper - Air Conditioning Coils

Air conditioning companies are offering two different types of coils in their home comfort systems, copper and aluminum. For a long time, copper was the only option. This was not because they did not want to use aluminum but because they couldn’t. Copper is stronger than aluminum so it has to be used in places where rigidity is necessary such as inside compressors. If a manufacturer wanted to use an aluminum coil, for reasons to be discussed later, then that manufacturer would have to find a way to connect the aluminum coil to the copper connection on the compressor and that’s where the serious problem was. Bonding the two metals together was no easy task and almost always insured leaks. That pushed the aluminum coil idea off the drawing board and straight into the waste basket.
So why use aluminum coils?
1. General Properties
Manufacturers can twist and bend aluminum in ways that they haven’t been able to do to copper. This allows them to use “micro channel” coils that are now being used in car radiators in air conditioners as well. This allows great heat transfer which translates to efficiency. Other companies are using it to make “spine fin” coils which basically look like a large pipe cleaner to disburse heat. Basically, aluminum has properties that allow it to easily be shaped which allows engineers to make new, more efficient designs.
2. Formicary Corrosion
Throughout the rest of the central valley, formicary corrosion has become a very serious issues costing some homeowners and building owners exorbitant amounts of money. Manufacturers blame the corrosion on a whole lot of different things including pollution but the bottom line is that so far, formicary corrosion has only been seen on copper coils, and not aluminum coils. It’s a corrosion that causes lots of microscopic leaks in an air conditioning coil usually requiring that at least the coil be replaced, and sometimes, the entire unit. For more information about formicary corrosion, view our article about it by clicking here.
3. ‘Deter Thieves
Most thieves are looking for one thing, copper. If they know that your system doesn’t contain the stash of copper that they are looking for, they will move on. A thief that steals $100 worth of copper can cost the building owner thousands of dollars in repairs or replacement costs because in the process of stealing the copper, they will destroy an air conditioning system.
4.  Cost
The cost of aluminum is simply cheaper than the cost of copper.
Are there reasons not to use aluminum?
The main reason not to use it is because aluminum is really hard to fix when there is a leak. It is possible to repair but the odds of having to replace the coil instead of brazing it, is high.

The aluminum coil is not the key to fixing all of our heating and air conditioning problems but it looks like it is a step in the right direction.