Spray Poly
Foam
Part-3
"Build it Tight and Ventilate it Right"
Healthy Indoors 47
Long-time IAQ industry consultant John Lapotaire
provides a detailed look at the Good, the Bad, and
the Ugly aspects of SPF in the third of his four-part
series for Healthy Indoors Magazine
even help reduce the workload on your HVAC
system thanks to its high R-value and efficiency.
In fact, with spray foam, HVAC sizing can be
reduced as much as 35% without the loss of ef-
ficiency or comfort.
That being said, with some luck you've already
read my previous articles and have asked some
very critical questions prior to making your final
decision about insulation. Not all insulation
products are created equally and the differ-
ences between SPF insulation and blown or
batt insulation go well beyond the R-value and
energy savings. SPF reduces your home's air
leakage and infiltration, which is great for ener-
gy efficiency but might not be so great for your
indoor air quality (IAQ) if the application is done
without proper consideration of the changing
ventilation needs of your home post-application.
When you reduce your home's air leakage or
air infiltration rate by insulating with SPF, you
are also substantially reducing its air change
rate (ACH), which can lead to the accumula-
tion of volatile organic compounds (VOCs) and
other harmful substances in your home. By far,
