While many homes in the Pacific Northwest do not have mechanical air conditioning systems installed, more and more people buying homes are looking for ones that do have air conditioners and/or heat pumps installed (a heat pump is basically an air conditioner running in reverse). Whole house air conditioning systems are becoming more and more ubiquitous and are therefore something home owners need to understand. As an inspector I have to admit that when I’m inspecting a home on a hot day, I’m kinda pleased when I quickly find the air conditioner. I have to test it, so I know the interior portion of the inspection promises to be cool and comfortable!
How does an air conditioner work? Luckily, we as users of the systems do not need to understand the science. Suffice it to say that a refrigerant is moved through the system and is subjected to changing amounts of pressure. Those changes in pressure cause the liquid to become a gas and then a liquid again, and that process of change creates different temperatures.
Many of us are old enough to remember the ozone crisis. Humans were causing the release of gases, primarily chlorine, that was then rising into the atmosphere, damaging ozone and causing a thinning of the ozone layer above the arctic. A primary culprit was the refrigerants being used at the time, and an International treaty that became known as the Montreal Protocol, signed in the late 1980’s, called for an elimination of those refrigerants.
The primary refrigerant used in home air conditioning systems at the time was R-22. The EPA mandated that production or import of R-22 (along with others) for use in new systems was to be phased out in 2010. In 2015 the production or import of R-22 became limited to the purpose of servicing existing systems, and in 2020 the servicing of existing systems could rely only on recycled or stockpiled supplies.
In 1991 the Honeywell Corporation developed a new refrigerant: R-410A. It has no chlorine, does no damage to the ozone layer, and is today the most widely used refrigerant in the world. The problem this changeover created for those who own air conditioning systems is that the two refrigerants are not interchangeable. R-410A operates at much higher pressures than R-22, and while it is technically feasible to retrofit a system designed for R-22 to use R410A, it is not practical or cost effective. If your AC system uses R-22 it can still be serviced, but beginning in 2020 the only R-22 available for that servicing will be either recycled or from existing stockpiles. The resulting costs will rise exponentially.
So even though we are entering the twilight zone for systems that use R-22, things are all good, right? No more ozone problems. That’s true… but the issue now is Climate Change. Everyone knows about the impact of carbon dioxide on our atmosphere, but it is not the only chemical challenging our climate. Chemicals are now rated on a Global Warming Potential scale (GWP). For purposes of measurement and analysis, the GWP of carbon dioxide is set at 1. The GWP of R-410A is 2088. R-410A is 2088 times the problem of a similar amount of carbon dioxide, at least when taken at face value. The use of R-410A is more energy efficient than the use of the older R-22, complicating any comparative analysis.
Even as we complete the changeover from R-22 to R-410A, we can be certain that a replacement for R-410A will be found and we will be going through another transition not very far off in the future.
As a homeowner, if you have an air conditioning/heat pump system that uses R-22, be aware that its retirement is fast approaching whether the equipment is worn out or not. If you have a system that uses R-410A, you have some time left. If you don’t have an air conditioning system, you might consider opening the window and waiting to see what comes next!