Why Choose Spray Foam Insulation?

Posted May 20, 2009 02:01 by Robert

Tags: spray foam, icynene, bio based

When you are thinking about reducing your energy requirements and carbon footprint, it makes sense to first address the demand side of the equation. Regardless of whether you are using gas, propane, electric, or oil, if you can reduce the amount of energy your house needs to heat and cool itself permanently from any of these energy sources, you will have an important impact on demand.  The best way to reduce your heating, ventilation, and air conditioning (HVAC) demand is to have a tight building envelope. Spray foam insulation can help to reduce your HVAC demand enough to downsize your HVAC equipment by about 30%. Make sure you tell your HVAC contractor if you are using spray foam because if they don’t adjust their load calculations (called  Manual-J )for the increased insulation, you will waste money on oversized equipment and have a system that cycles on and off too often.

There are a few claims about spray foam insulation that I have found misleading. The first is that it is not as green as other forms of insulation because it does not have a high amount of renewable or recycled content. This is a classic case of how you want to define “green.” Recycled newspaper and denim jeans might be very green in terms of their content, but they are also very flammable and to be used as insulation, they need to be doused in fire retardant. I am very leery of fire retardant as recent studies have shown elevated levels of fire retardant appearing in the bloodstream and the long-term effects of this are unknown, but it can’t be positive. In most cases, spray foam insulation itself is not flammable and therefore does not require any additional fire retardant, although it does require a fire barrier such as wallboard in open spaces. The second claim is that the R-value of spray foam is less than fiberglass. In a laboratory this might be true, but it does not have much to do with the real world. Fiberglass cannot get into corners in the same way as foam. Also each outlet or recessed light on an exterior wall that you install and cut around for fiberglass takes away dramatically from R-value. The reality is that spray foam insulation at a lower R-value will outperform fiberglass by a factor of two to three times due to the tightness of the seal and the reduced air infiltration.

Bottom line, spray foam insulation gets my vote as a safe and smart choice for your new home or renovation, which will pay for itself in a few years.

E-mail | Permalink | Comments (2) | Comment RSS