HFC stands for hydrofluorocarbon, a manufactured combination of hydrogen, fluorine, and carbon atoms. HFCs are found in blowing agents used in spray foam roof adhesive and insulation. Without HFCs, roofing insulation wouldn't "foam up," expand and deliver the tremendous thermal resistance (R-value) a building needs. HFCs are also found in refrigeration and air conditioning systems.
There's a big problem with HFCs, though. HFC emissions cause increased warming in the stratosphere, reports NASA, speeding up the chemical reactions that destroy ozone molecules and decreasing ozone levels.
In other words, HFCs trap heat in our atmosphere and contribute to global warming. Thus, they have high global warming potential (GWP) and are ultimately bad for the environment. How bad?
"Though HFCs currently represent around 1% of total greenhouse gas," explains the Climate and Clean Air Coalition, "their impact on global warming can be hundreds to thousands of times greater than that of carbon dioxide per unit of mass."
Washington State Department of Ecology adds that "if their use isn't stopped, HFC emissions will increase to 7–19% of global greenhouse gas emissions by 2050."
Do HFCs in roofing materials really contribute all that much to the problem? Yes. Global HFC consumption in the building foams sector accounted for ~38 million metric tons of carbon dioxide in 2010, according to the U.S. Environmental Protection Agency.
Phasing out HFCs could do more than benefit the environment. It could also prompt improvements in the energy efficiency of air conditioners, refrigerators, and other equipment that rely on these chemicals, notes the Clean Air Coalition.