Fiberglass vs Vinyl Replacement Windows

[jgrady53]

Has anyone had any experience with fiberglass replacement windows? Are they truly the best replacement technology out there for insulation and noise reduction? We are shopping windows, and it seems they are double the price of vinyl. Is vinyl subpar to fiberglass?

[Windows on Washington]

Different materials and different pluses and minuses to each.

Fiberglass is typically be about 1.5X times the cost of a premium vinyl.

For the sake of comparisons, lets stick to premium vinyl vs. Fiberglass.

You will get better thermal numbers out of premium vinyl when comparing apples to apples (i.e. double pane, triple pane, 5 layer, etc).

Fiberglass can be painted (more easily) and is more thermally stable (less expansion and contraction than vinyl).

Sound transmission has about 99% to do with the glass and much less the frame.

Fiberglass (being comprised largely of glass) does not, by itself, have as good an R-Value as vinyl. All premium frames will usually be insulated with some sort of foam so this issue is somewhat mitigated.

Fiberglass has more tensile strength and rigidity when compared to vinyl of similar thicknesses. This is the reason that most fiberglass windows can get away with thinner profiles.

To say one is sub-par to the other is probably not accurate. It all depends on what you need your window to look like and do.

[jgrady53]

Thank You .. that helps a lot.

[holmmd]

I'm new to this so take this for what's it worth...one of the manufacturer's I talked to said fiberglass has a better look to it as it gave a closer appearance to wood. He may have been trying to sell me on the higher priced prodcut but I have a similar question so thought I would share.

[Randy]

When it comes to appearance, specifically a wood like appearance, you can't beat Marvin's Infinity. Not the best performer, but hands down the best looking.

Sunrise Vanguard windows with simulated divided lites are one of the better vinyl windows for the wood window look, IMO.

[Shims]

So why do fiberglass windows typically cost a lot more? As far as air infiltration numbers are concerned, is it safe to say high end vinyl windows like soft lite have a much lower air infiltration rating? I can't even find Marvin's air infiltration ratings anywhere.

[Windows on Washington]

The cost of manufacturing a lineal of fiberglass is significantly more than vinyl. The cost of assembling that window is also more.

That would likely amount to about a 20-30% increase in overall cost to manufacture.

The Infinity air leakage rating on the DH is a 0.27 the last time that I checked. I sell the window and that is one of the things that I am not a huge fan of.

[Shims]

So the Impervia can't be that bad of a window then right? It has an air infiltration rating of 0.3 on DH models, design pressure of 30, U-Factor of 0.3 and SHGC of 0.25 with advanced low e glass and foam insulation. I've read online about people not liking the way it looks but it's been out since 03 and has gone through design changes; personally I really like the way it looks. One of the things I like about it is that it doesn't have that flat, two dimensional, plastic look to it. Frame has more depth to it.

[Windows on Washington]

I am not a huge fan. It does not stand up well to the Marvin Infinity by comparison and they are usually competitively priced.

[HomeSealed]

In fg, I like the Marvin better as well. That being said, my beef with the Impervia is looks coupled with Pella's terrible customer service. Product-wise, you could certainly do worse, altough it would not be my choice.

[Shims]

Is it true that vinyl windows are more prone to seal failures? Or is that only low quality, builders grade vinyl? Because I've been in many houses in the 90s that have the original vinyl windows with fog between the glass panes. I've seen more seal failures in vinyl windows than wood. Believe me I'm a realtor.

[Skydawggy.]

Vinyl in windows does not cause seal failures, inferior spacers do. I'm pretty sure the bad seals you have seen are in old style box aluminum spacers.

[masterext]

your a realator? you probably see more seal failures on vinyl because most old wood windows are single pane not double. a fiberglass will not have a lower seal failure rate than a vinyl. why? material has nothing to do with seals failing. thats where the spacer as well as the sealant quality come into play.
Pella has a .3 air leakage number ! thats a ridiculously high number especially since premium vinyl windows are well under a .1 . the lower the number the better. the impervia is not comparable to a marvin and also not comparable to a premium vinyl window.

[buddy11]

Is it true that vinyl windows are more prone to seal failures? Or is that only low quality, builders grade vinyl? Because I've been in many houses in the 90s that have the original vinyl windows with fog between the glass panes. I've seen more seal failures in vinyl windows than wood. Believe me I'm a realtor.

Vinyl windows have evolved and improved dramatically since 1990. Today's vinyl windows are very sturdy compared to 20 years ago. Most of the seal failures you see are most likely due to dated spacer systems.

[Shims]

Are Andersen windows really as good as people say they are? I got a quote for 11 andersen 400 series tilt wash full frame windows. 9 were double hungs, 1 was half circle, and 1 was a picture window. $8500. price included insurance, labor, fiberglass insulation, pvc brick moulding, etc. It seemed a little low. Was it a good thing I didn't go with that quote? It made me suspicious.