Question

My AC service contractor wants to sell me a new unit with environmentally friendly Freon. What does that mean? Should I buy it?

Asked by Ellen Stover
Tampa, FL

Answer

Steve Saunders

Answered by Steve Saunders

Irving, TX

TexEnergy Solutions, Inc

July 29, 2010

There is both good news and no news in this question.

The “good news” is the fact that your air conditioning service company recognizes the inherent improvement of the R-410A refrigerant that will need to be installed with your new air conditioning unit / system. The new refrigerant (Freon, as many people call it) has no ozone-damaging CFCs or HCFCs (hydrochlorofluorocarbons). This is good for you and for the environment.

The “no news” is that you and your contractor have almost no choice of systems. HVAC manufacturers, by law, have not been allowed to make systems using HCFCs since the beginning of 2010. While there are a few of the HCFC-22 (also known as R-22) units left in circulation, they are increasingly unavailable.

Environmentally friendly Freon is the kind that does not contribute to deterioration of the atmospheric ozone layer. The change has been coming for quite a while (mandated by the Montreal Protocol, an international environmental agreement) and is good for your comfort as well as for your energy efficient home.

Your choices are as follows:

  • Repair: Pay your HVAC service company to repair whatever is broken. In an older unit, this often means compressor replacement. Replacing a compressor is a good choice if there are insufficient funds to replace the AC unit / system or if you expect to leave the home in the not-too-distant future and you do not expect to get a return on your investment.
  • Replace with an R-22 unit: These units will still be available for an undetermined amount of time. The numbers are rapidly diminishing. They are generally of lower SEER value and, over the life of the unit, they will likely have higher operating (utility bill) and maintenance (repair) costs. However, given the right scenario, this could be a reasonable financial choice.
  • Buy a unit with R-410A, environmentally friendly Freon: In every instance where there are financial criteria other than “lowest first cost,” you should strongly consider buying a new system.

It is great that your company understands the new products. That speaks well of them. There have been a surprisingly large number of HVAC service companies that have not understood the rules about AC units with 410A refrigerants.

These new 410A products come with different names for this type of refrigerant. The best-marketed brand name is from the Carrier Corporation and is called Puron. This name is a catchy riff on the trade name of Freon and has been a well-deserved marketing winner for Carrier for over a decade.

A few additional thoughts as you evaluate HVAC replacement proposals:

There are some important elements to think about as you contemplate replacement of your unit and a change of refrigerant.

  • Getting the size of the system right: In the past, when electricity was less expensive, the general concept was “bigger is better.” Today, we know that the best strategy is running a load calculation and “right-sizing the system.” Often, this means reducing the size of both the indoor and the outdoor units for your system. You need to know what environment makes you and your family comfortable. Humidity levels are almost as important as the measured temperature, and right-sizing usually makes your home more comfortable by lowering the humidity. Right-sized systems also cost less to operate on an annual basis.
  • Matched systems: Effective air conditioning comes from a system. The system usually includes a compressor bearing unit located outside your home and an indoor unit that has a fan designed to blow air over the coil and through the duct system to the home. The evaporator has a device that changes the pressure of the compressed refrigerant, and when the pressure is reduced, the coil gets cold. When the air runs over the coil, water condenses (humidity is removed from your home) and the air temperature gets lower because it is exposed to the cold evaporator coil -- thus creating colder air. It is important to have the size of your systems matched (engineered ratings are the best method) and to have the right pressure-changing device (a thermal expansion valve, i.e., TXV) to get the best results. (Note: there are other expansion devices that were good selections in their time. Today, I would insist on having a TXV!)
  • Get a new indoor coil: You will need a new evaporator coil to go with the new outdoor unit. The size is one element, the expansion device is another. Also, the new Freon operates at a significantly higher compression ratio, and without the proper match of the coil to the condensing unit you simply will not have a system that functions properly and efficiently.
  • New or existing refrigerant lines? -- that is the question. These lines are made of copper and run from your indoor coil to your outdoor unit. Generally, they will be hidden by walls, floors, or ceilings. Many manufacturers’ guidelines still recommend new refrigerant lines. If possible, it is a good idea. However, it is often difficult and always expensive to replace these lines. At our company, Tempo Mechanical, we have been installing Puron systems for a long time. The very first replacement unit was installed in my home in February 1999. For many reasons, we did not change the Freon lines. We did do a really good job of evacuation (getting the old Freon and the old oil out) from the existing lines. The unit has performed very effectively and the utility bills are very reasonable for the size of home. I am OK with owners who elect not to change the refrigerant lines.


For more information:

Check GreenHomeGuide's nationwide directory of green HVAC contractors.

Read Steve Saunders' Ask A Pro Q&A, "I keep hearing that I should get a home energy audit. What should I expect to pay and expect to get?"

Tagged In: heating cooling, summer energy

Do you have a question about greening your home? GreenHomeGuide invites you to Ask A Pro. Let our network of experienced green building professionals – architects, designers, contractors, electricians, energy experts, landscapers, tile & stone specialists, and more – help you find the right solution.