Yes, absolutely there are differences, and the consequences for the earth of picking the wrong one can be significant.
Here is the problem: some foams, especially closed cell foams, use a blowing agent that can be a severe ozone-depleting hydrocarbon (remember the old HFCs and CFCs) or gases with high global warming effects, with some lasting in the atmosphere for over 250 years.
- Examples of these are HCFC-141b, CFC-11, and HFC-23.
- BuildingGreen did a great analysis (read ithere) on some of the common foam blowing agents and came to the conclusion that using these foams did so much damage as a result of their global warming potential that the payback from the reduction in fossil fuel usage was not positive (meaning you were not doing something positive for the planet) for somewhere around 36 years.
- Interestingly, almost all, if not all, of the blowing agents used today in home foam insulation were created to replace refrigerants that had very high ozone-depleting potential, so even the bad ones today are better than what we had a decade ago.
Better blowing agents are available
The good thing is that some of the blown in insulation manufacturers are paying attention and are using the no-Ozone Depleting Potential (ODP), low- or no-Global Warming Potential (GWP) blowing agents (essentially a refrigerant gas that stays in the foam and slows heat movement through the foam cells).
I recommend foams with blowing agents like:
- HFC-245fa (called Enovate 300),
- HFC-365 mfc, and also
- blowing agents with hydrocarbons such as pentane, cyclopentane, and isopentane (flammable, so really only for exterior usage), and
- the best yet, the new fourth-generation blowing agents like Honeywell's HBA1, and DuPont's FEA-1100, which are just now coming to market.
How to choose
Because the blowing agents fill the cavities of the foam bubbles, and are the main component of the foam involved in heat movement through the foams, the thermal energy characteristics, or thermal conductivity, of the blowing agents largely define the energy efficiency of the foam itself -- so choosing effective blowing agents is crucial to a good insulation.
Fortunately, the consumer does not need to mix and match the right foam with the right blowing agent, but really only has look at the:
- performance characteristics and the
- Ozone Depleating Potential (ODP) and the Global Warming Potential (GWP) of the foams themselves.
Natural foams are not appreciably better
Also, but unfortunately, the so-called natural foams derived from things like soybeans or other agricultural crops are only between 1% and 5% "organic" and the rest is petroleum-based materials.
So these are not really appreciably better, more natural, or more efficient than normal, non-organic foams.
It should be noted that the term "organic," while commonly used to mean a natural or grown material, actually refers to any molecule that contains carbon, so is used incorrectly in the lexicon of everyday life, because both natural materials like corn, beef and people and "non-natural" materials like oil, gas and plastics, contain carbon.
For more information:
Also, read Andy Ault's Q&A "Do you recommend bio-based soy foam insulation?"