I’ve been pretty vocal about a big problem with some of our most common insulation materials: that they are made using blowing agents that are highly potent greenhouse gases. Extruded polystyrene (XPS) and closed-cell spray polyurethane foam (SPF) are made with HFC (hydrofluorocarbon) blowing agents that have global warming potentials (GWPs) many hundreds of times greater than that of carbon dioxide. (My apologies for contaminating this column with so many acronyms!)
Insulation materials help our homes save energy and, in so doing, they reduce the combustion of fossil fuels and the release of greenhouse gases. But if the insulation material itself is made with a very-high-GWP blowing agent that may ultimately escape from the insulation, adding a lot of insulation may actually be a bad thing from the standpoint of mitigating climate change. All that was spelled out in my column two years ago.
With XPS, the blowing agent HFC-134a has a GWP of 1,430, meaning that it’s 1,430 times as potent as carbon dioxide (which is defined as having a GWP of 1). Nearly all closed-cell SPF is made with the blowing agent HFC-245fa, which has a GWP of 1,030. Relative to global warming, these blowing agents aren’t as bad as CFCs that were used originally, but they are as bad as the HCFCs (hydrochlorocfluorcarbons) that were adopted as second-generation blowing agents. (Both HFCs and HFOs are considered totally safe for the ozone, which is
Anyway, given all this I’ve been closely following the developments by industry in coming up with alternatives that are neither ozone depleters nor significant greenhouse gases. Two years ago, it appeared that the leading candidates were HFOs (hydrofluoroolefins). And indeed, it was just announced last week that Whirlpool, the nation’s largest appliance manufacturer (with such brands as Maytag, Amana, Jenn-Air, and KitchenAid, along with Whirlpool), was switching to a new HFO blowing agent for the polyurethane insulation in all of it’s refrigerators.
Whirlpool will be using the new Solstice Liquid Blowing Agent made by Honeywell, one of the nation’s three producers of blowing agents (along with DuPont and Arkema). Solstice HFO has zero ozone depletion potential and a GWP of just 4.7 to 7.0 -- similar to that of the various hydrocarbon blowing agents used in expanded polystyrene and polyisocyanurate -- and insignificant relative to global warming.
Further, Solstice HFO will boost the R-value of the insulation material slightly. Compared with HFC-245fa, this HFO produces insulation with 2 percent higher R-value, and compared with hydrocarbon blowing agents it offers an 8 to 10 percent improvement, according to Honeywell.
While the change is exciting, it is not immediate. The HFO has just received it’s approvals from the government, and it will take a while to ramp up production and convert refrigerator factories to the new foam. Whirlpool expects to begin incorporating the new blowing agents into it’s refrigerators in late 2013.
But what about the closed-cell SPF insulation that is commonly used to insulate buildings? SPF manufacturers will probably be replacing the HFC-245fa with HFO ... but it’s unclear exactly when that will happen. Rick Duncan, the technical director at the Spray Polyurethane Foam Alliance (SPFA), the trade association serving the SPF industry, told me that some SPF manufacturers ("system houses") are conducting field trials with the new HFO blowing agents, but not all of them. Unlike in 2003 when federal regulations mandated a switch from HCFC to HFC blowing agents due to ozone depletion concerns, there are no similar regulations requiring a switch from HFCs to HFOs.
And the conversion takes time and is expensive -- about one year and at least $100,000, says Duncan. With the building industry still in an economic slump, producers aren’t looking to spend a lot of additional money on product development.
Duncan believes, however, that when a new life cycle assessment (LCA) report on SPF comes out that SPFA is now finalizing, customers will begin asking for lower-GWP foam and manufacturers will respond by producing it. From an environmental standpoint, open-cell SPF (which doesn’t include HFC blowing agents) has just 1/20th the environmental impact as closed-cell SPF.
I was unable to get an immediate answer from the Extruded Polystyrene Foam Association about when the HFC-134a would be replaced with a lower-GWP blowing agent and whether there is a gaseous form of HFO that could work for that industry. (While a liquid blowing agent is used in producing SPF, a gaseous blowing agent is required for XPS.)
Both of these industries have already gone through two major transitions: from CFC to HCFC blowing agents and then from HCFC to HFC blowing agents. With a weak building economy and depressed sales of building materials, enthusiasm for a third major conversion has been limited. But I believe that there will be growing demand to produce products with as little impact on global climate change as possible--and if this year’s heat and drought continue, that demand may well grow.
Alex Wilson is the founder of BuildingGreen, Inc. in Brattleboro. Send comments or suggestions for future columns to email@example.com.