People doing home repairs have a number of different options for insulation materials, from cellulose and polystyrene, to fiberglass and foams, and it might be difficult for individuals that aren’t professional contractors or handymen to choose the best product for their needs. For a long time, insulation options were more limited, and fiberglass was generally considered the superior option. Within the last decade, however, the landscape has changed and foam has supplanted fiberglass as the product of choice for educated insulators.
When you scientifically measure the results of the different insulation options, it is foam that is shown to have the greatest R-Value -- a measurement of the “Real-World” effectiveness of a product. 2-pound closed-cell foam is shown to have an R-Value per inch of nearly 7, compared to just under 4 for rigid polystyrene panels and a mere 2.5 for pink fiberglass batts. In other words, foam is more than twice as effective as fiberglass.
The reason for this is that even the smallest gap in insulation will dramatically impact its effectiveness, and it is very difficult to install fiberglass so that it is entirely gapless. Even “perfectly installed” fiberglass will tend to have some small imperfections, and the fact is that the vast majority is not perfectly installed. What makes these gaps so problematic is that when it gets cold – the time when effective insulation is most important – the material contracts, and those gaps widen. In effect, the more you need your fiberglass insulation, the less effective it becomes. Spray foam insulation, in contrast, starts as a liquid and then expands into a solid, completely filling any gaps that exist, so that even in extreme cold the coverage is seamless. Beyond just making your home feel more comfortable, this also lowers your heating and cooling costs as you no longer have to compensate for the inefficiencies of other insulators.
Spray foam also has a number of benefits, beyond just temperature control, that other types of insulation materials do not. Air quality is one of those areas where foams excel, as fiberglass can contribute to volatile organic compounds, CFCs, and other fibers and loose particles, and the inevitable gaps can let in other outside pollutants and dust. Those gaps also let in outside noise, meaning that foam insulators are also more efficient for creating a quieter, more acoustically sound home. Another of the benefits to spray foam is that it is a more environmentally friendly insulation material. The energy that you save with foam, instead of fiberglass, what with reduced heating and cooling needs, saves the average 2000 sq. ft. home an equivalence to taking almost 700 SUVs off the road, and it is the product of more sustainable materials.
You have your choice of a number of insulating products, and any of them are better than nothing; however, when you consider all the available factors, closed cell polyurethane foam is the superior choice for a better R-Value, economic value, and environmental impact -- so talk to your contractor about which materials they are using on your home, or, if you are doing it yourself, make sure you are making an educated decision regarding your insulation choice.