Installation-Winteq Foam vs Fiberglass Batt

I have two different installers wanting to to use two different types of insulation around windows during installation. One uses something called Winteq Foam while the other says he uses a fiberglass batt insulation. If it makes a difference, the foam would be on Simonton 5500 casements and the fiberglass on Sunrise casements. Does it really make a difference what is used? Thanks in advance to all!

Fiberglass is okay as long as it is air sealed. If not, it is worthless and does nothing for the home.

Inquire as to how he plans to seal the window to home connection.

WoW is right, fiberglass is useless if the cavity is not completely airtight. Air passes right through fiberglass, which is why it is often used for air filters.

I agree with both of my peers. Additionally foam has water sealing advantages.
So it insulates, air seals, and water seals.

One more vote for foam.

Thanks for all of the replies. The installer who wants to use fiberglass has additionally said that using foam will void a majority of the warranties on vinyl replacement windows because it can expand and shift the postion of the window causing problems with opening and closing. Ever heard of that explanation?

I'm not aware of any manufacturer who considers the use of foam something that would automatically void their warranty per se. However, anything done during the installation process that cause the window to fail will invariably void any warranty. So if the installer uses standard foam that is made to seal holes in brick and misapplies it causing the frame on a vinyl window to bow, that will void the warranty. However, using low expanding foam properly will not bow the frame and thus, the proper use of it will not affect the warranty.

Eco is right on.. In the past there were some manufacturers who said it could not be used, however, pretty much everyone is on board now. The key - as Eco alluded to- is proper choice of material (low-expansion, closed cell), and proper application.