Published July 2012: Updated January 21, 2014
I Have Gas: CFCs, HCFCs and CO2
The year was 1987. I was in elementary school and had just been taught a horrible truth about the impending doom caused by the depleting Ozone layer. I was especially terrified by a chart that vividly showed a bleak outlook for the future year 2010, where if nothing was done to curb CFC emissions, the ozone layer would largely be depleted and the Earth along with its inhabitants would fry under the ultra-violet radiation of the sun.
Well, fortunately due to international government regulations (making it illegal to use CFCs), this ozone depleting trend was curbed and our Earth's ozone layer was saved. In 2003, scientists declared that the ozone layer was on the mend. In another 50 years, it may be completely healed from all the damage we humans inflected.
While the ozone layer has quietly been salvaged and we humans have (for the most part) escaped death by sun burn, climate scientists are now finding that the gasses that replaced the ozone depleting CFCs are still hazardous, but for different reasons.
While CFCs deplete the Ozone Layer, increasing ultra-violet radiation from the sun, HCFCs like R-22 and HFCs like R134A and R410A (refrigerants used in automotive and newer home air conditioners respectively), while far less damaging to the ozone layer, are still thousands of times more potent than CO2 at contributing to global warming. Darn!
On a side note, ozone depletion dimmed the effects of global warming while greenhouse gasses enhance it.
Common Refrigerants: CO2 has a Global Warming Potential of 1. It is the baseline gas to which all other gasses are compared.
|Refrigerant||Global Warming Potential||Ozone Depletion Potential||Application|
Why are we worrying about CO2 when there is so much concern with the more potent R-22 and other harmful greenhouse gasses?
Consider the tiny volume of R-22 that is found in a typical central air conditioner. In a closed loop and left alone, none of the R-22 will ever negatively impact the environment or contribute to global warming. According to an online HVAC forum, the average central A/C only has 4 lbs of R-22 inside its closed loop system. As long as the system never leaks, none of this environmentally damaging gas will ever do any harm.
From my understanding, R-22 is harmful because when vented into the air, it remains up in the atmosphere for hundreds if not thousands of years, preventing the Earth's heat from diffusing into space.
If a typical central A/C was to develop a leak and vent all 4 lbs of its R-22 into the atmosphere, that would be the equivalent (Global Warming Potential or GWP) of releasing 1700 X 4 lbs = 6800 lbs of CO2 into the air.
A typical central AC uses about 2000 KW-Hr of electricity during the summer season. Using the US average for CO2 emissions from generating electricity, running a typical central A/C for the season (2000 KWH worth) would release 2734 lbs of CO2 into the air. Using cheap, coal-powered (and natural gas) electricity from Utah, that same air conditioner will cause 4092 lbs of CO2 to be released each season. Those living in the US, you can find emissions for your local area here.
In only 1-3 seasons of use, the air conditioner itself will do more environmental damage just from consuming electricity (generated by fossil fuels) than if it were to develop a leak and vent all 4 lbs of R-22 refrigerant. If a home is more energy efficient, the air conditioning will not have to consume as much energy (less air pollution at the power plant) and end up being less of a contributor to global warming.
The best way to reduce your home emissions (without sacrificing convenience and luxury) is to increase the energy efficiency of the home.
You can also find out how much refrigerant your central A/C has in it by looking on the name plate located on the outside unit. It will be higher or lower depending on the total separation between the outside unit and the inside one. My central AC is a very large 6 ton unit and has over 13 lbs of R-22 in it. At $44/pound, that's almost $590 worth of R-22 refrigerant. Wow! Having a leak in the refrigerant line will not only contribute to global warming, it is also expensive.
Just as government regulations on ozone depleting propellants and refrigerants have so far prevented a global catastrophe, for global warming reasons, it is also illegal to vent refrigerants like R-22 directly into the air.
If our central AC developed a leak and all 13 lbs 6 oz of R-22 refrigerant leaked out, it would vent the equivalent (Global Warming Potential) of ~11 tons of CO2 into the atmosphere. Our home and central AC are pretty efficient but even so, it would take 3 summers of running the central AC to match the equivalent of 11 tons of CO2 (that is created while making dirty Utah electricity). That one mistake of leaking out the R-22 refrigerant would negate years worth of environmental awareness and pro-activity.
Updated: January 2014: R-410A
All newer air conditioning systems (including our recently installed ground-loop heat pump) now use R-410A instead of R-22. While it has zero ozone depleting potential, it still has a very high global warming potential (1890 times greater than CO2) if allowed to leak out into the atmosphere.
What About This Global Warming Hoax?
While there are a few groups (most with deep ties to fossil fuel interests), that refuse to believe the validity of global warming, there is a total scientific consensus among all national science academies, of all major industrialized nations that it is real and human activities are the main contributor.
In the scientific literature, there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused mainly by human-induced emissions of greenhouse gases. No scientific body of national or international standing disagrees with this view, though a few organizations hold non-committal positions.
Air Conditioning Tips:
I found a cool site with lots of ways to save energy and money on air conditioning. Here are my favorite tips from their website:
You will use 3 – 5% more energy for each degree your air conditioner is set below 24° C (75°F), so set the thermostat at 25° C (77° F) to provide the most comfort at the least cost. The less difference between the indoor and outdoor temperatures, the lower your overall bill will be.
Personally, we prefer a colder house. With ceiling fans going, I can tolerate the AC being set at 75°F but not a degree higher. If I am idly lying around the house, 75°F is comfortable. Against my energy conserving nature, we crank the A/C for increased comfort and luxury.
Every increase of 1.7°C (3°F) on your thermostat can result in a reduction of 15% in air conditioning energy use and can result in significant savings on your summer electric bill.
I made some simple modifications to our central air conditioning system. This reduced our total home electrical usage 22% (or about 11.4 kWh per day) all summer. You can do it too. It's pretty easy and didn't cost very much. Click here to find out how.