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Complaints about fiberglass windows — plus what is the next best thing?

We are building a house in Quebec province, Canada — so very cold winters and hot / sometimes humid summers. We were set on installing fiberglass windows triple / double panes according to exposure of lot (mainly southern and eastern with a little western and very little northern.)

However, we attended a home building fair recently and two of the window / door suppliers we came across said they had stopped supplying fiberglass windows / doors as there were too many technical problems and complaints from customers as well as major issues of supply / service from the companies involved. The issues cited were: cracking frames, peeling paint, leaking, warping, pooling etc. We were also told that with a new build, the fact that the house will take a few years to 'settle' means that using a more rigid frame like fiberglass is riskier....

Obviously, we realize that as suppliers of alternative products, they may not always be the most objective and at the end of the day, we need to weigh up all the good press fiberglass gets with these negative comments. We would welcome your thoughts on the above.

Also, if we did decide not to go with fiberglass, what would be considered the next best alternative for low U and high SHGC & VT windows?

Asked by Tango B*
Posted Jan 22, 2012 10:37 PM ET
Edited Jan 23, 2012 6:10 AM ET


12 Answers

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Ahh.. Poor Thermotech... They certainly get some bad press from dealers in the national capital region.

When the only people saying how bad fibreglass windows are, are the reps who carry something else, well, 2+2 = 7.

Answered by John O'Brien
Posted Jan 22, 2012 11:09 PM ET



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One of the statements in your list of problems rings true -- "complaints from customers as well as major issues of supply / service" -- but only for one company, as far as I know: Thermotech Fiberglass Fenestration.

The other Canadian manufacturers of fiberglass windows -- Accurate Dorwin, Inline, Duxton, and Fibertec -- have pretty good reputations for service.

The other listed problems -- "cracking frames, peeling paint, leaking, warping" -- are mostly nonsense. Concerning "pooling," any window, including a fiberglass window, can have installation problems leading to water leakage. Install your windows carefully.

I'll leave it to others to recommend windows that don't have fiberglass frames. However, I will say this: fiberglass frames will always outperform and outlast vinyli.

Answered by Martin Holladay
Posted Jan 23, 2012 6:08 AM ET
Edited Dec 3, 2014 2:20 PM ET.


Thanks for these answers - very helpful. We have heard positive stories also about Inline and Fibertec. If we had to pick one more, would you go for Duxton or Accurate Dorwin? Thanks a lot

Answered by Tango B*
Posted Jan 24, 2012 2:36 PM ET


While I can not vouch for the quality, I have been in contact with all the companies above except Duxton. All of their service has been top notch and fast responses. Accurate Dorwin has probably had the best service and responses of them all in my experience thus far. They also were the highest priced below Thermotech. Inline and Fibertec were close with Inline the cheapest. AD was pretty comparable to Fibertec. Thermotech was a good 5-8k higher then the rest.

Answered by Jesse Lizer
Posted Jan 25, 2012 11:20 AM ET


So I would agree that the problems spoken of are isolated to ThermoTech Windows.
Fiberglass windows are among the most resilient in the market, but like any product, small manufacturers sometimes cut corners, and problems result.

SeriousWindows in an excellent option for very high performance windows. After building high performance green housing in Ontario and Quebec for the past 10 years- I'm now involved with the company distributing for SeriousWindows in this region, and we offer excellent pricing on very high performance fiberglass frame windows. We have now placed these windows in everything from LEED platinum targeted homes in the Eastern Townships, to federal government buildings.
To ease your concerns- They have a lifetime guarantee and a well capitalized company to back that guarantee.

If you are really scared off from fiberglass we can also offer a very high performance vinyl window as well- but Fiberglass is really my preferred choice.

You can reach us at 866-970-9888 to get sample pricing.

Christopher Sweetnam Holmes

Formida Windows and Doors (Distributor for Serious Windows )

Answered by christopher sweetnam-holmes
Posted Jan 27, 2012 6:52 PM ET
Edited Jan 27, 2012 6:54 PM ET.


Hi Christopher,

I've been following this thread:


for quite some time. Have any of your customers experienced problems like those described in the thread? Serious Windows (and associated distributors) take quite a beating from some of the posters! Although THIS thread is more about the quality of the fiberglass, service counts in large amounts as well!

Answered by Jeff Nelson
Posted Jan 27, 2012 7:45 PM ET
Edited Jan 27, 2012 7:46 PM ET.


I recently got a triple-glazed Fibertec. I thought the price ended up being quite good, and if it performs as the sticker claims it should, I'll be happy with it. It came in the 8-10 weeks that I'd expected. And, although they did mess up my order, I got the impression they would have swapped it out for me without much hassle; however, the one they sent was workable for me.

In short, at this point, I'd order from them again.

Answered by Mojave Disaster, 3B
Posted Jan 27, 2012 9:15 PM ET


Response to Jeff Nelson.

We've been extremely pleased with the quality of SeriousWindows products.
The complaints I've seen on the other thread seem to be related to a bad dealer, this is truly unfortunate butthis is not the normal experience with Serious Windows Fiberglass dealers, who are generally passionate green builders and designers themselves.

I agree completely that service is an essential component of any window sale, and generally I would suggest that no matter who you buy windows from -
Ensure that it is a company that ;
1-has knowledgeable, competent staff, that take the time to service you well and the time to understand your needs, and explain how to get the best value from the products.

2-Has a local salesperson who can be on site at your project, should you need help for any reason, installation, warranty etc.

3-a manufacturer that you trust will handle any warranty and customer service issues with professionalism, and has the financial capacity to back the warranty.

We strive to ensure that we offer such service to our clients in Canada, and we sell excellent SeriousWindow and SeriousGlass products, which have a 30 year history in high quality buildings from small passive houses to the Empire State Building.

What we most like about working with serious, and why we chose to distribute SeriousWindows over all other fiberglass window brands, is that
1.They are putting significant money, research, and resources to build a truly NorthAmerica wide high performance window brand.
2.Serious is a glass manufacturer first and and window manufacturer second- and glass performance is the most important part of any window.
3.Serious has a great team of passionate employees who want to delivery great product.


Christopher Sweetnam Holmes
Formida Windows and Doors (Distributor for Serious Windows in Eastern Canada ) 1- 866-970-9888

Answered by christopher sweetnam-holmes
Posted Jan 29, 2012 10:33 PM ET


Thanks for replying, Christopher.

Answered by Jeff Nelson
Posted Jan 30, 2012 12:28 PM ET


I am building a house outside of Ottawa presently and have recently purchased fiberglass windows. I have been to the Thermotech plant (it is a 15 minute drive from my home) . I received very good service from them during the "shopping phase" and cannot complain. The sales rep or the company owner and chief engineer answered all of my questions.

No doubt though, their reputation suffers from a very poor BBB rating, which may or may not be connected to their split in 2005 from 'the other' Thermotech window company in Ottawa that is a retailer and supplier and not a manufactuer. I do not know the whole story. My decision was based on price more than anything, as we were desparately trying to squeeze the project into our budge and every penny matters. But I admit the reputation issue also factored into the decision to buy from Fibertec. I didn't want to take the chance on such a large investment. I don't have the windows yet, by fibertec has been terrific.

I hope thermotech gets this issue straightened out because I would hate to see this company, by all rights a true innovator in this area, disappear from the scene. With respect to some of the other triple glazed options, we looked at triple vinyl - it was not much cheaper and and was - well, vinyl! The wood options from Europe seem very good buy much more costly. They were out of our budget.

John Scime

Answered by John Scime
Posted Feb 11, 2012 9:10 AM ET
Edited Feb 11, 2012 9:11 AM ET.


Hi Tango, who were the companies involved with the fiberglass supply / service issues in your 1/22/12 post?

Answered by Kelson E.
Posted Feb 18, 2013 11:07 AM ET


I've also recently had windows installed from Fibertec and agree the service was great and the windows are top quality. I'm glad chose them over the other manufacturers you mentioned.

Answered by Jim Norton
Posted May 14, 2013 7:25 PM ET
Edited May 14, 2013 7:27 PM ET.

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