Vinyl vs Fiberglass Windows

Home : Recommendations : Vinyl vs Fiberglass Windows

Compare Vinyl vs Fiberglass Windows And Doors

If you are debating between vinyl vs fiberglass windows, here are four factors to take into consideration (strength, style, energy efficiency, and window cost) in order to determine which is a better option for your home.

Dane - Site Editor - Original Publish Date - August 10, 2013
Page Last Updated On September 23, 2024

Quick Links

Strength

Style

Energy Efficiency

Cost / Value

Homeowner Questions And Answers

Comparing Vinyl vs Fiberglass Windows

Strength Comparison

In terms of strength, the edge goes to fiberglass. Fiberglass manufacturers claim the material is eight times stronger than PVC (vinyl). I think this is overstated myself, but the material is some multiplier stronger than vinyl windows (although there is going to be variability here based on the particular wall thickness of each window - which goes back to how well or how poorly the factory constructs their molds). In general, you can expect a fiberglass window to last long than a comparable vinyl series.

However, the question of strength is more or less a moot point because any good to great fiberglass/vinyl window is going to be plenty strong for nearly all residential applications. Windows aren't holding up walls - they're not load bearing in any way. (Please note my use of the words "good to great" windows - cheaply made vinyl window models or series can be a different story.)

The one caveat here is very wide openings. In these scenarios, it's smarter to use two wndws mulled together in order to span the opening. If the window opening is too wide and you use a less than stellar window, you risk the frame bowing over time. This is where a knowledgable installer comes in very handy and why we want you reaching out to quality local companies, instead of the ones with the cheapest prices.

Bottom Line: Fiberglass Wins - While both of these materials are plenty strong, fiberglass gets the nod. This material should last somewhat longer, although a really top tier vinyl window can last 40 years without missing a beat.

Style Comparison

In terms of style, there isn't much difference between these two materials. Most people are hard pressed to tell the difference between vinyl and fiberglass windows, even right close up. So in this case, it's going to come down to the particular window and brand that you choose. There are some nice looking options in both materials.

For instance, I'm not a fan of the Pella Impervia - I think it looks cheap and flimsy. But I love the look of the Marvin Elevate series and Essential Collection - I think Marvin makes great looking windows (I just wish they had better air infiltration ratings.) There are plenty of cheap, bad looking vinyl windows - too many to mention really.

(Check out are picks for the worst window brands here.) The Polaris UltraWeld with an interior wood laminate, on the other hand, is one of my favorite window series out there. The inside looks like real woodgrain, while the profile is clean and stylish. Add to this almost unbeatable performance numbers and I find this series at the top of my recommended list!

Bottom Line: Fiberglass Wins - on the style, question, it all comes down to personal taste. So get out there and see and touch the different window series you are interested in using as replacements.

Energy Efficiency Comparison

The common wisdom is that fiberglass is the more energy efficient material. However, the Marvin Infinity fiberglass window has an air infiltration rating around 0.18, while the Okna 800 has an air infiltration rating of .01. On the other hand, the Alpen 625 fiberglass Series, available in limited states, is an amazing performer and I would pick this option over even the Okna 800 for its stella R value and air infiltration rating. Alpen Windows Reviews

So which material is really more energy efficient? I would say this: high end vinyl windows are going to be more energy efficient than high end fiberglass wndws, unless you go with Alpen or Inline - those two specific brands. However, lower end vinyl series get pretty poor energy efficiency ratings and there are a whole lot of mediocre to poor vinyl wndws out. (Interesting note: there are VERY FEW low end fiberglass windows on the market.)

What is probably true is that vinyl will lose a bit more of its energy efficiency than fiberglass over time. Please note: installation will also play a very big role on the energy efficiency of your windows - this is why we always suggest finding a very reputable installer that can offer quality installation.

Bottom Line: No Clear Winner The energy efficiency of a window is pretty specific to the particular model you buy. Both top tier vinyl/fiberglass windows should deliver very solid energy efficiency. Low end vinyl windows have pretty poor energy efficiency numbers, which makes sense - you get what you pay for.

Cost / Value Comparison

Fiberglass windows prices will run approximately 35% more than comparable vinyl-series. This is the big equalizer if you will - many consumers are sold on fiber glass until they see the price per window cost. Let's put fiberglass windows cost at $800 to $1600 fully installed. So a mid range fiber glass series will run $1200 fully installed.

Let's put vinyl windows cost at $400 to $1200 fully installed. Notice the considerable difference in the low end cost spectrum between these two materials. Vinyl $400 / Fiberglass $800 - the reason for this is that there aren't many low end fiber glass window options out there because there's no market for it.

Bottom Line: Vinyl Windows Handily For me personally, I think there is more value in a high end vinyl-window. however, if you are in your forever home, fiber glass is an excellent option - if you can afford the rather hefty price tag.

Homeowner Questions And Answers

If you have questions on vinyl vs fiberglass windows, we have answers - well I hope we do at least! Ask us a question and we'll do our best to answer it.

Dane - Site Editor

Top Fiberglass Window Options

Thanks Bill for your recommendations. I am curious if you have fiberglass windows you'd recommend? I'm also curious to hear what scenario you would suggest getting a fiberglass window over a top tier vinyl? (For reference: we live in Southeast Wisconsin) I feel a bit stuck deciding between the two. Thank you.

Anne - Homeowner - from 2024

[Site Editor's Answer]

Anne, my list of great fiberglass windows includes the Marvin Essentials, Marvin Elevate, Marvin Infinity, Inline Windows, and the Milgard Ultra Series. Fiberglass is typically 35% more than vinyl so it is usually out of reach financially for many when compared with vinyl. Our sister site has a good article comparing the two. I think a high quality vinyl is the way to go, but that is just my take.

Dane - Site Editor - from 2024

Ohio Replacement Window Recommendations

Good morning, I stumbled onto your youtube videos and have been very impressed with your objectivity and easy to understand analysis. What are your recommendations for the Cleveland Ohio area? We are moving into a 20 year old home with original builder windows.

So – likely to do vinyl clad (although composite has some attraction but probably above the budget), double hung, expected time in the home 20 years. Would like to minimize the frame size if possible (I know that would probably be a composite one – so please let me know what VINYL might do that instead). I

Tom - Homeowner - from 2024

[Site Editor's Answer]

Hi Tom, fiberglass would minimize frame width, but they are going to run 30% more than vinyl. Marvin, Inline, and Alpen are top brands in this space.

I also recommend a high quality vinyl window with a interior laminate - I think this is the best of both worlds as you get the look of wood (they used to look bad, but not they are pretty impressive).

Dane - Site Editor - from 2024

Vinyl vs Fiberglass

Dane, hi, can you please help me with a few things? First, I was wondering about vinyl. It seems there are a lot of people who really doubt vinyl's durability, given how much it expands and contracts. But on the other hand, I heard that quality vinyl windows should last 25-30 years, while the more durable wood vs fiberglass windows may only get you another 10 years.

So I'm just wondering your thoughts on how well vinyl is expected to hold up with the latest windows.

Also your take on warranties would be helpful.

David - Homeowner - from 2024

[Site Editor's Answer]

David, the expansion contraction problem used to be an issue and still is on crappy vinyl windows, but not on the ProVia Endure window or any other top tier vinyl windows. I still think they are the best product for the price. Fiberglass is probably more durable in the long run but I just don't think that makes up for the 35% cost upgrade...

I look at the warranties of products as a statement from the manufacturers about how long they think their product should last. Vinyl is pretty much the longest - lifetime - although I don't think that after 40 years a company is going to run out and replace all of your vinyl windows - I tend not to put much stock in warranties in general - too many things can change - I'm a cynic.

Dane - Site Editor - from 2024

List For Southern Wisconsin

I am looking to replace most of the windows in my house. The windows I have now are nearly 30 years old. Could you please send me your list of recommended windows for the southern Wisconsin area? I am thinking of choosing a high quality vinyl window. Fiberglass would be nice too but I am concerned about the budget for this material.

Thank you for sharing your knowledge and recommendations!

Sheryl - Homeowner - from 2024

[Site Editor's Answer]

Sheryl, happy to send along my list of recommendations!

Dane - Site Editor - from 2024

Fiberglass Window Options

Dane, thanks for all of the information on vinyl windows. Any suggestions on fiberglass options?

Pedro - Homeowner - from 2023

[Site Editor's Answer]

Pedro, Marvin is always a trusted brand with their Marvin Elevate and Essential Collection.

Alpen and Inline are also very good — but they have pretty limited availability.

Fiberglass will run 35% more than vinyl on average. Fiberglass is the stronger frame, but a really well made vinyl window with an excellent build and top-of-the-line components will often beat the fiberglass model on performance. Both excellent materials for home windows — but the vinyl option has to be the really well made series (there are hundreds of mediocre options out there.)

Dane - Site Editor - from 2023

Window Replacement In Marietta, Georgia

Hi Dane, I found you through a recommendation on Reddit. I am in Marietta, Georgia and need to replace close to 40 wood clads that are about 30 years old. I am looking at vinyl or fiberglass (not sure which is better) and am trying to keep costs down with the sheer number I need to replace. The website said to email you for a recommended list of windows. I'm looking for any recommendations I can get and appreciate anything you can send my way.

Jennifer - Homeowner - from 2023

[Site Editor's Answer]

Hi Jennifer, yes I am happy to send you our list -- in terms of vinyl vs fiber glass, I would stick to a high quality vinyl, unless you can afford fiberglass. The link in the previous sentence goes over all of the pros and cons in detail so you can suss out which material is a better fit for your home and your budget!

Dane - Site Editor - from 2023

Marvin Windows vs KHPP

Project is 16 windows and two sliding patio doors. Marvin essentials collection for most. Large 120x78 window had to upgraded to the ultimate line to fill the frame without losing any space.

$35,500 including labor and taxes.

Doors are 3570 a piece. I should mention this is with black frames inside and out. The large picture window did drive the price up by about 2k but I made that decision so I wouldn’t lose any window space.

I had other quotes from RBA, a local KHPP retailer, and a few other chains. All I asked them for was windows, not doors. They were also all vinyl except RBA)

RBA with JUST windows: $39k - Renewal By Andersen Reviews

KHPP JUST windows: 29K

Others between $30K - $35K for just windows

Leaning toward the Marvin option Its by far the lowest price with the best windows I’ve gotten so far, and I trust the installer highly recommended. I know it’s expensive, but as long as im getting what I pay for im happy. Just want to make sure im not getting screwed.

Thanks for your time and all of your info on vinyl vs fiberglass windows - very helpful so thank thank you.

Dan - Homeowner - from 2023

[Site Editor's Answer]

Dan, I think the two strongest options here are the Marvin Essentials at $35K (I'm assuming this does not include the patio doors???) or the KHPP at $29K. I think I would be leaning toward the KHPP option although you didn't mention which series. They have three -- the Genesis, Ascent, and Meridian (which is their best). Even the Genesis is good though. I think I'd prefer this option to the Marvin, but I could go either way on this - Marvin makes an excellent fiberglass window. KHPP Windows Reviews

Dane - Site Editor - from 2023

Window Material Question

Hello Dane, hoping you can give me some recommendations for quality vinyl windows. I live in the Dallas metroplex. Shopping for the following:

2 small single hung
4 large sliders
4 small sliders (located in bathrooms and a dressing area)
2 large fixed picture windows

The large fixed pictures are located in the front of my house, and I want them to look very good and not change the look of my front elevation (except to improve upon it). I need the grids to be affixed on the outside of the glass. Do you think Windsor would be a good match for the fixed windows? Do you have a recommendation that you feel might be better? Windsor Windows Reviews

Thanks for any assistance you might provide in this matter. By the way, I'm a senior which is why I'm looking at quality vinyl with a good warranty. Makes no sense to me to purchase more expensive fiberglass vs wood windows.

Thanks again.

Brenda - Homeowner - from 2023

[Site Editor's Answer]

Brenda, here is my list of good and great windows for you to take a look at...I would avoid wood clad windows myself -- they are gorgeous to look at, but honestly they don't provide a ton of value and they won't last as long as a good vinyl.

When it comes to vinyl vs fiberglass vs wood, I think a good quality vinyl is probably the best option for 80% of all U.S. homeowners.

Here are my Texas based recommendations:

Dane - Site Editor - from 2023

Are Fiberglass Windows Better Than Vinyl

John, thank you so much. Shopping for windows has been an ordeal...lots of smoke and mirrors from companies and reps. You have provided some of the best information I've seen to clarify this murky process.

Leaning towards the fiber glass because of the strength and color retention but will check out the top tier vinyls that you suggested. The two fiber glass windows in our area are Pella Impervia and Marvin Infinity. Any take on these two?

Thanks again!

Richard - Homeowner - from 2023

[Site Editor's Answer]

Richard, he Marvin Infinity is a very good series. The Pella Impervia is not one that I would buy. That is my short and sweet take on those two options :) Pella Impervia Windows Cost

Dane - Site Editor - from 2023

Fiberglass vs Vinyl

I have 18 single hungs (builder grade) that I'm looking to replace in Charlotte, NC. 14 are 72x32, 4 are 60x32, 1sliding patio door 8ftx6ft

I'd really love to get an unbiased professional opinion on what to get. Also I'd love to hear if you are a fan of fiber glass or vnyl. Thank you.

Paula - Homeowner - from 2023

[Site Editor's Answer]

Paula, here is my list of good and great brands for you to take a look at. In terms of vinyl vs fiberglass/composite/wood -- I think there is more cost value in a high quality vinyl window. Fiber glass is a great option, but it typically runs 1/3 more and that typically puts it out of most people's price range (plus top tier vinyl series outperform many but not all fiber glass options).

Wood clad usually lasts 25 years and then needs to be replaced, so I don't often recommend it. I think for where you live, vinyl probably makes the most sense. Let's see what you come up and go from there!

Dane - Site Editor - from 2023

Vinyl vs Fiberglass Cost

Sorry to bother you again Dane. So just a recap, the infinity by marvin bit was about 30k for 10 windows. I got in contact with Pinnacle Window and Siding of Woodstock. They claim to be the only authorized okna dealer is GA. I had them quote the Okna 600 vs 800. 600 came in at $12.5k and the 800 was 1$2.8k. Needless to say after every quote being 25k or more prior to this I'm blown away!! Do you think I've found a "too good to be true" situation? They also offer the Starmark Evo. Worth the extra for composite?

Alex - Homeowner - from 2023

[Site Editor's Answer]

Alex, no bother at all -- so Pinnacle Window and Siding gets excellent reviews. The Okna 600 and 800 series are both excellent windows and honestly they get way better performance data than the Infinity. They are two of the best vinyl windows on the market. I'd prefer to have these in my home over Marvin Infinity fiberglass windows any day of the week. (Although I do love the Marvin Infinity series - a very solid option.)

I don't think it's a case of too good to be true. I think it's more that fiberglass windows are expensive and a high quality vinyl window is much more cost effective. My opinion anyway...

I personally think the Okna Starmark composite series is also excellent, but not really needed in Georgia. In Wisconsin, I think there is a very good argument for the extra cost, but not for the climate in which you live.

Dane - Site Editor - from 2023

Vinyl vs Fiberglass Windows Question

Thank you for the very quick reply. One concern I had with the vinyl. Again in GA, and the back of my house is west. I've heard thay vynil can expand quite a bit with heat causing seal failures. Is that something you'd be concerned about for longevity? I'm 32 and plan to be in this house for well over 30 years. Thabk you again.

Alex - Homeowner - from 2023

[Site Editor's Answer]

Alex, the vinyl-window expansion contraction issue was a concern a decade ago and I believe continues to be an issue on cheap vinyl options. What I recommend are all top tier series that really don't have this issue -- most vinyl series have a lifetime warranty, while the Marvin Infinity as an example comes with a 25 year warranty - I believe that's right. I don't put much stock in warranties to be honest, but I do think its a solid indication of how long the manufacturer thinks their product will last. That's one of the reasons I trust in vynil , although fiberglass is great also. It's just that fiberglass windows cost roughly 35% more than vinyl so it tends to put them outside the price range of many consumers.

If an Alpen HPP dealer is in your area, that would be great. They make an AWESOME fiberglass window -- but it can be quite pricey.

Dane - Site Editor - from 2023

Barndominium Options

Hi Dane, I am planning to build my daughter a barndominium in the 27524 zip code later this year.

The metal building erector suggested I use replacements in case something happens and they have to be removed. The metal clad walls makes new construction window's difficult to replace.

I was wondering what you though of vinyl vs fiberglass windows? What do you recommend for my area for double hung design with low E coating on the glass?

Thank you.

John - Homeowner - from 2023

[Site Editor's Answer]

John, I think either material is just fine as long as it is a well made window brand and series. Either material will hold up if they are a quality product and you have great installation. Here are my picks for the best fiberglass windows out there.

Dane - Site Editor - from 2023

Vinyl vs Fiberglass Windows In Colorado

Hey Dane ... we live in Fort Collins, Colorado. We're looking to replace all our casement windows, the front door, and a hinged patio door on our 1998 one-story ranch home. Our issue has been the inside of our aluminum (I think), double-paned windows. The window glass has held up well, but the interior wood casing, if that's the right word. The horizontal wood at the base of the windows is cracked and peeling. I have sanded, primed and re-painted, but it just cracks and flakes again. It's the one thing that makes me feel like our house is "old". (We had our glass re-sealed a few years back, but that didn't resolve the issue. So ... couple of questions:

1) Am I just not doing a good job of repairing and need to hire a professional painter?

2) Have been looking at fiberglass just because I'm so sick of fighting a losing battle. That said, they're very expensive, and it sounds like you think the high-end vinyl windows are just as good or better. Would love to get any specific feedback you might have, as well as your list of recommended Colorado window replacements.

Amy - Homeowner - from 2022

[Website Editor Answers]

Wood windows are a losing battle :)

I would look at high end vinyl windows myself. Here are my Colorado vinyl window recommendations: [pulled for duplicate content worry].

Dane - Website Editor - from 2022

Vinyl vs Fiberglass Question

I'm primarily struggling with greater durability of fiberglass/vinyl (given the last 10 years of pulling my hair out with the wood). Also, and much less important, kind of like the idea that if I wanted to change color schemes down the road fiberglass can be painted. Whether those things are worth 30-40% premium is my current consternation.

Amy - Homeowner - from 2022

[Website Editor Answers]

Amy, A top tier vinyl window should have no real issues at year 20 in terms of the durability of the frame -- not for residential purposes. The parts and hardware are more likely to fail so that should be the bigger factor -- that's why I like vinyl over fiberglass for most homeowners. The painting part is a different story. You can paint vinyl but it usually voids the warranty, but at year 20 most warranties are more or less a moot point anyway. Window Replacement Prices

Dane - Website Editor - from 2022

Related Topics: Window Prices By Size