With dangerous heat headed our way, how bad is your air conditioner for the environment?

  • Tim Newberry of Anna, Illinois, checks air-conditioner units to make sure they're up and running properly. Hydrofluorocarbons from properly running air-conditioner units won't hurt the environment, but increased electricity use from them can.

    Tim Newberry of Anna, Illinois, checks air-conditioner units to make sure they're up and running properly. Hydrofluorocarbons from properly running air-conditioner units won't hurt the environment, but increased electricity use from them can. Ceasar Maragni/Southern Illinois Local Media Group, 2018

Updated 11/30/2022 12:48 PM

As parts of the Chicago area respond to dangerously high temperatures this week, millions of air-conditioning units will kick into action to provide much-needed relief, hiking energy usage and utility bills alike.

The heat wave sweeping across the region Tuesday and Wednesday is in line with predictions that extremely warm days will only continue to increase in Illinois. In the last century, the average daily temperature in the state increased by 1-2 degrees, a recent study found.


As people turn to their cooling systems for relief in an increasingly hot climate, scientists say we are paying an environmental cost: air-conditioning units typically run on potent greenhouse gasses called HFCs, or hydrofluorocarbons.

The good news is that HFCs do not escape into the environment while an A/C unit is running properly. The bad news is that when HFCs do escape -- during manufacturing, if the unit is leaking, due to improper disposal -- they can trap up to thousands of times as much heat in the atmosphere as carbon dioxide.

Despite the high global warming potential of these chemical components, homeowners don't have to worry too much about leakage, said Ralph Muehleisen, chief building scientist at Argonne National Laboratory.

HFC leakage is primarily a risk in places with extensive refrigerant piping such as supermarkets, he said.

In these cases, there are a few solutions on the market right now, and a whole lot more under research, said Nenad Miljkovic, co-director of the Air Conditioning and Refrigeration Center at the University of Illinois at Urbana-Champaign.

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Miljkovic said one roadblock to widespread replacement of HFCs is that many of the alternatives are flammable.

Another, larger challenge is that the systems that are currently installed across the country -- not only in houses but in cars, refrigerators, office buildings and more -- have been optimized over decades.

In a lot of cases, these chemical compounds can't be dropped in without additional accommodation. In other words, replacing HFCs is often difficult and expensive.

If policy or law doesn't require that overhaul, "companies are just going to stick with the status quo and keep things as is," Miljkovic said.

Energy usage

For individuals, Muehleisen said an air conditioner's greatest threat to the environment stems from the fact that it uses electricity -- which typically runs on nonrenewable resources and is the largest source of greenhouse gas emissions in the country.


Around 90% of all Illinois households use air conditioning, and the cooling systems account for about 12% of total home energy expenditures.

With the state moving toward 40% renewable energy by 2030, residents will be able to use electricity with less wear on the environment.

Until people make the switch to a cleaner grid, scientists say the easiest way to mitigate contribution to global warming is to be mindful of air-conditioning usage and keep the thermostat a few degrees higher. According to the Department of Energy, ceiling fans are especially efficient and "will allow you to raise the thermostat setting about 4 degrees Fahrenheit with no reduction in comfort."

Residents should try to limit air conditioning to one or two rooms, especially for those who rely on window units, Muehleisen said. Using shades and blackout curtains to block the sun's rays also helps.

For people who may be thinking about replacing their units with more efficient versions, Muehleisen said to wait until their current air conditioner is unusable. He said the amount of energy saved from a new model isn't substantial enough to offset other costs involved in retiring a unit that is workable.

Muehleisen also said that because hot air rises, residents should check that their upper floors and attics are not trapping too much heat. This is especially important for buildings that have black or gray roofs.

If the temperature inside begins to surpass the temperature outside, residents should open the windows or use an attic fan to displace the hot air.

Muehleisen said turning off electronics that aren't needed such as lamps and computers also goes a long way.

"Every bit of electricity coming into your house turns into heat," Muehleisen said. "It's not only wasting electricity, it's generating heat."

• Jenny Whidden is a Report For America corps member covering climate change and the environment for the Daily Herald. To help support her work, click here to make a tax-deductible donation.

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