Making Closed Cell Foam Green

If you recall this post, I talked about how the process of insulating our house with closed cell foam would result in the emission of HFC-245fa, a Green House Gas (GHG) with around 1000x the warming potential of carbon dioxide, but which decays from the atmosphere very quickly, in 7 years instead of 400. My solution to reducing the GHG footprint is to track the amount of the B chemical used, which contains the GHG, to calculate the carbon dioxide equivalent released, and then to buy carbon credits of a variety that will take carbon out of the air for up to 80 years, long after the HFC-245fa has decayed.

But carbon credits are always a last resort, when you don't have a choice: flying, whatever part of your gasoline usage you can't get rid of through an electric or hybrid car, and, as in our case, fossil gas and electricity drawn from the grid that can't be offset with renewables or eliminated by efficiency. It would be really great if we could figure out some way to make closed cell foam more green and, in addition, make it more accessible to the average home owner. So here are some thoughts along those lines.

Closed cell foam is a really super insulating material. It's positive properties are:

• Inexpensive relative to even better insulators, such as aerogel
• Nontoxic
• Best insulating value of any affordable material (R-6/inch, approximately)
• Easy to install
• Functions as an air and vapor barrier
• Can be partially made with recycled and plant-based  material

It would be really great if we could figure out some way to reduce its negative properties:

• Costs 2-3x as much as fiberglass batt, which is a lousy insulator
• Uses petroleum for the part that is not recycled and plant-based, unlike alternatives such as blown cellulose, which is completely made of recycled material
• Installation releases HFC-245fa, a powerful GHG

Some folks would include the fact that it burns when exposed to flame as a negative, but I don't necessarily see that. Fiberglass batt doesn't burn, but the paper casing will, and of course so will the studs and other structural materials in a house. As long as there are no additives that produce toxic fumes, the foam itself will simply combust to carbon dioxide and water. Most houses these days have far more stuff in them that will produce toxic fumes when burned.

Let's walk down this list one by one.

First off, cost. I frankly have no idea why closed cell foam is so expensive. Cost for a particular product or  service is generally the sum of the cost of materials, cost of equipment (amortized over some period of time), and the cost of labor.

Is it because the materials that go into closed cell foam are more expensive than fiberglass batt or blown cellulose? I can imagine that they might be somewhat more expensive because they are specialized chemicals, but 2-3x more expensive?

Is the equipment more expensive? Ponzini parked a trailer in front of our house that contained the spray equipment.  Though I didn't see their equipment, I've seen it before when we had open cell foam sprayed into the garage and attic wall. It is obviously more expensive than a staple gun, but I wonder if it is more expensive than the spray device they use to  install blown cellulose? And, in any event, they can amortize it over a lot of jobs.

Is the labor more expensive? It took Ponzini maybe 6 days, 10 AM to 4 PM, to finish our house (well, let's put it this way, they think they are finished, the thermal imaging test will tell if they really are). I can't imagine that it would have been any more or less time than if they had installed blown cellulose or fiberglass batt. Actually, I think it probably would have been more time with either because both require that the installers actually get up to the walls and staple something on: the batt itself for fiberglass batt or netting to keep the cellulose in with cellulose. With foam, they just need to aim the spray gun and fire. It's certainly messier, bits of foam end up everywhere (including in our front driveway where they would pose a menace to aquatic wildlife if they got into the bay) but I'm sure fiberglass batt and blown cellulose installation have their unpleasant aspects too.

Aside from a possible slight difference in cost of materials (and of course absent any hard data),  my conclusion is the exaggerated price difference between lousy insulators such as fiberglass batt and closed cell foam is simply because closed cell foam is a "premium" product and therefore must command a "premium" price. In other words, you get what you pay for. To get the same air and vapor barrier function as closed cell foam with batt or cellulose requires all the cracks in the building's thermal shell to be sealed and the installers to pay close attention to how they are installing the material, all of which would make batt and cellulose more expensive too. Such measures won't increase the R-value of batt or cellulose, of course. In any case, I'd certainly like to find an insulation contractor who wouldn't mind someone taking a look at their cost structure and really getting some hard data on the topic. After all, if the computer industry pricing and cost structure worked the way the building industry seems to work, we would all still be using PCs with 386s and 640K of RAM because the fast Pentiums would be way out of our price range.

Next, use of petroleum. I'm no chemical engineer, but I think that there should be a way to increase the recycled and nonpetroleum content of closed cell foam. Demlec already advertises that it uses soy oils and partially recycled content in its product. If I were an academic with a chemical engineering background, I'd be writing grants to EnergyARPA and the Energy Dept. to do research on the topic. And, let's put it this way, the long term future of petroleum-based products is pretty much known: they will shortly be gone. According to the International Energy Agency, we'll be almost out of oil by 2050.

Finally, GHG emissions. On the face of it, this seems like it might be the most difficult point, but actually, its the easiest. HFC-245fa is used because it's nontoxic, much heavier than air (so the bubbles expand more slowly),  and relatively inexpensive. It's a good choice, except for the greenhouse gas problem. If there were some way we could keep it out of the air...hmm...this brings to mind something that happened when we first bought our house.

The roof had termites. So we had to have it tented. During tenting, the pest control company encases the house in a large, closed tent and fumigates with sulfuryl fluoride, which is extremely toxic to anything that's alive (we had some plants damaged when we had it done) and is itself a green house gas 4800x as powerful as carbon dioxide. There are now more environmentally benign alternatives, we didn't investigate them at the time, since they probably didn't exist. 

Why not enclose a house undergoing closed cell foam insulation in a large tent, sealed as tightly as possible, just like when tenting for termites? While the foaming is going on, a blower can pull air out of the house containing the HFC-245fa and exhaust it through a system that recovers the GHG for reuse. It might also be burned, but the fluorine in the HFC could end up as hydrofluoric acid, which is really nasty stuff. Left behind is the HFC in the foam bubbles, some of which will outgas over time, but the amount that's released during such aging should be much less than during installation. This could then be offset using carbon credits.

Tenting will add something to the cost, but if my suspicions about why closed cell  foam is so  expensive are true, the cost could still be reduced enough that closed cell foam should become  much more competitive with fiberglass batt.


So there's some ideas about how to make closed cell foam cheaper,  less impact on non-renewable resources, and less GHG-polluting.