Foam inserts vs spray foam inside window frames

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djodts
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Foam inserts vs spray foam inside window frames

#1 Post by djodts »

Hi

My wife and I had a few companies come out to provide quotes. All showed the corner cutouts which revealed the construction of their windows. Nearly everyone had foam filled cavities for their vinyl frames except one. One company (the one we actually preferred due to many points) had one concern. Instead of the chambers being filled with spray foam, they were filled with polystyrene foam inserts which left a little gap of air in the chamber. I am sure that the foam will still provide insulation, but I am curious if anyone has insight into it actually being significantly inferior.

Thanks for your input

Doug

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Randy
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Re: Foam inserts vs spray foam inside window frames

#2 Post by Randy »

There's really not a difference at all in terms of performance. One top-tier window manufacturer switched from spray-in to inserts and their Air Leakage rating is still a .01, so I don't think it makes a difference either way.

Window4U (IL)
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Re: Foam inserts vs spray foam inside window frames

#3 Post by Window4U (IL) »

I think windows with the foam inserts are actually slightly superior, not the other way around. Many manufacturers have switched from spray foaming to foam inserts to get higher foam content. I've personally been at three major manufacturers over the years where I saw first hand that extrusions that were being cut to size weren't always 100% filled and had large air voids. Two of these manufacturers I was at have now switched to foam inserts.
A lot of the thought of spray foaming being superior comes from the experience of foam filling a void while installing a window keeping air from leaking through. But, when the foam is in a window extrusion that has welded corners there is no air leakage to worry about. Because of this I think the inserts are just as good if not better.

djodts
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Re: Foam inserts vs spray foam inside window frames

#4 Post by djodts »

Thanks for all the replies. My concern is actually on heat loss through radiation, not necessarily air flow, so does that change any of your thoughts?

Thank you again
Doug

masterext
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Re: Foam inserts vs spray foam inside window frames

#5 Post by masterext »

The foam insert is always full length. Heat loss is not an issue at all. There is an inherent issue with spray foam, its somewhat challenging to fill the entire extrusion with foam and thats why a few companies made the switch to foam insterts which are molded to fit tight amd snug.

djodts
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Re: Foam inserts vs spray foam inside window frames

#6 Post by djodts »

Thank you

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Windows on Washington
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Re: Foam inserts vs spray foam inside window frames

#7 Post by Windows on Washington »

+1 to the previous comments.

While we recommend foam, strongly, the fact is that in the case of the vinyl extrusion we utilize...the outer chamber is thermally bridged to the outside and foam makes a significant difference in the thermal performance.

I was previously not a fan of the inserted rigid foams, however, the manner in which they are cut now it tension fit for 100" fill and is the superior and more consistent way of filling chambers in my opinion.

The critical consideration for an inserted foam is that it be snug and form fit inside the frame.

Delaware Mike
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Re: Foam inserts vs spray foam inside window frames

#8 Post by Delaware Mike »

I agree with the other Pros. Going back 15-years when I sold some of the Great Lakes vinyl series their foam inserts seemed completely inferior to filling the extrusions with spray foam. I've seen the process in person in which Soft-Lite and Sunrise fills their chambers with injected spray foam, and while I feel confident that they do a nice job, the properties of the product will allow it no randomly leave hollow spots in the extrusion during the curing process and there is no way to tell.

I really like the manner in which OKNA is adding their foam inserts. They do a real nice job at it. The test results don't really show any difference from what the engineers have told me so I prefer to have the sure thing in the form of the inserts. I can tell you that the position of plant employee that has to inject the foam into the uncut extrusions is the low man on the totem pole. That job flat out is awful. Tyvek suit, respirator, rubber gloves, googles, all inside of a hot plant. All day long, No thanks, been there working in that industrial environment before.

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HomeSealed
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Re: Foam inserts vs spray foam inside window frames

#9 Post by HomeSealed »

Great and relevant comments above. Bottom line though is that the u value will ultimately determine the performance, in particular the heat loss. High density, low density, injected or pushed in, all that matters is the effect that it has on the U value of the product. When comparing foam vs no foam within the same model, look at the performance delta between the two. Likewise when comparing one brand to the next.

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