News Brief

Old Insulation and HVAC Systems Are Still Depleting Ozone

Older buildings are “CFC banks” because of phased-out refrigerants and blowing agents, according to MIT scientists.

The hole in the ozone layer is closing—but not as quickly as it should, according to researchers at the Massachusetts Institute of Technology (MIT). In fact, buildings with older foam insulation, HVAC systems, and refrigeration equipment could delay healing by six years. The escaping CFCs (chlorofluorocarbons) are blowing agents (used to produce foam insulation) and refrigerants. CFC-11 and CFC-12, which were phased out internationally after the signing of the Montreal Protocol in 1987, are also potent greenhouse gasses and will gradually leak nine billion metric tons of CO2 equivalent into the atmosphere between 2020 and 2100, “an amount that is similar to the current European Union pledge under the [United Nations] Paris Agreement to reduce climate change,” say the scientists.

Another source of unexpected ozone depletion and global warming is CFC-113, which is used only as a chemical feedstock but is also causing surprising impacts. According to the European Union, several ozone-depleting chemicals like CFC-113 are used in the manufacture of HFCs (hydrofluorocarbons, a class of non-ozone-depleting but high-global-warming-potential blowing agents and refrigerants still used today) and fluoropolymers.

“Wherever these CFC banks reside, we should consider recovering and destroying them as responsibly as we can,” according to Susan Solomon, Ph.D., an MIT chemistry professor.

More on blowing agents and refrigerants

The Cost of Comfort: Climate Change and Refrigerants

New Chemical to Reduce Climate Impact of Foam Insulation

Low Climate Impact of New Blowing Agents Confirmed

For more information:


Published May 4, 2020

Melton, P. (2020, April 21). Old Insulation and HVAC Systems Are Still Depleting Ozone. Retrieved from

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