Composite or fiberglass over pvc windows

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Posted by: from Winnipeg
6/18/2012 at 7:09:15 PM

Building an new house and not sure what to pick for windows. We are not looking to cheap out, but wondering if fiberglass or composite is worth the extra money over pvc.

In the past we have heard negative things about pvc, but now lots of suppliers are saying it has improved and they stand by their 25 yr warranty.

Can someone with experience please shed some light on this?


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Date/Time6/18/2012 at 8:36:50 PM

Around Winnipeg you have the best Window Manufacturers in the business. They could probably provide the best information as they are the best at what they do. These guys are the best in the World in their fields.

Good Luck

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Date/Time6/18/2012 at 8:49:03 PM

There has never been a problem with PVC windows. The problem is the 15,000 different manufactures. It doesn't require a lot of investment and no testing department to start a window company. Stick with the larger more established manufactures and you will do fine.

Fiberglass is a better window, more stable and can be painted or finished to look like wood. Unless you want the best, it's proabley not worth the extra cost.

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Date/Time6/18/2012 at 8:55:55 PM

Hi Jason:

I wouldn't use anything else but vinyl pvc windows. They are greatly improved over the older ones, and in B.C. they are filled with argon gas and have a sun screen rating. Essentially the window inserts are the same, but the insulation factor may differ with the frames.. Contact a reputable window supplier in your area for what is best. Sliders are cheaper than casement windows, and they sometimes can have a greater size range. Basically the window insulation is the key factor. Used a recommended foaming agent around the window. There are ones that are designed specifically for windows.

There are a great range of window applications for the home. Basic well built windows are the best value.

You can spend lots of money on different styles, double hinged, tilt and turns and so on.

Your best bet is a qualified window consultant. Get two or three prices on comparable products, but in the long run it boils down to two factors: a fair price, but who is the best installer.


Meadowood Homes

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Robert from Robert Graul in Montreal
Date/Time6/18/2012 at 10:09:33 PM

Hello Jason,

As with most significant purchases for your home...relevant homework with a reputable window supplier will pay off in the end. PVC windows are the industry standard nowadays...maintenance -free, low cost, and better engineering is why they now dominate the market.

Go to two local window shops, educate yourself from the salesman, purchase "LOW E" or enhanced energy efficient units, get a price from them... installed, make sure they do the measuring and make an informed choice.

Good luck with your project and have a great summer.


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Date/Time6/19/2012 at 6:40:03 AM

Fiberglass vs PVC

Fiberglass windows are very nice, Much better the steel or wood. However PVC is much more flexible. In our climate some days are -40then other day are +40.

Most PVC windows (when installed properly) Will shift with the house movement and can handale our climate. But where ever you go, window suppliers will Tell you they have the best product.

In Winnipeg I find the jelwin windows Are one of the cheaper PVC windows, but are the most used. The windows are nice and works good, and will keep you budget Down.

Then the polar windows I feel is the top of the line PVC windows in Winnipeg. The quality of their product is amazing, but also the service is very good. Any problems, they will be Easyer to deal with. Cost is much higher. But you get what you pay for.

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Date/Time6/19/2012 at 8:44:40 AM

As always, if you add up all the answers above you'll have a great reply, however, there are two more points worth mentioning.

Buy an ENERGY STAR qualified window package. You are in Zone C, so any window you get that is labeled Zone C will be toward the top of the industry's energy saving capacity. In vinyl, as in windows of all materials, there are great ones and there are crappy ones. You will probably get what you pay for, although there are companies who spend hours telling you why their products are worth more than anything else on the market and then sell you something not worth what you paid.

The second point is installation. particularly in new construction, most framers are not window installers. As a member of the CSA A440.4 committee that writes the installation standard I would never allow a window to be hung from a nail fin without also shimming and fastening through the shims. So, make sure that your window is being properly installed to avoid long term problems.

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Date/Time6/19/2012 at 10:21:57 AM

This is a very interesting question with a number of issues to consider.

1. Energy conservancy: the general understanding amongst the public is that PVC windows perform well in terms of 'R' value and generally do not conduct energy. Sadly, this is not true. Data illustrates that because the PVC frame is continuous from interior to exterior, there is a considerable amount of energy lost. In many cases aluminum clad wood windows are better performers in this area, with fibreglass window frames even better yet.

2. Dimensional stability: PVC has a tendency to warp and twist, especially when in direct sunlight. Furthermore, PVC could not be painted in the past (some products permit this now) or distortion due to heat was even more extreme. Also, adhesion of paints to PVC was poor at best.

3. Envronmental concerns: PVC manufacturers claim that this is a recyclable product, however I have yet to find a manufacturer that will reclaim old PVC window frames for recycling / downcycling. Municipalities generally will not accept PVC for recycling either. Studies have also indicated that the post-manufacturing of PVC has led to a number of unfortunate deseases, largely due to the high Chlorine content.

4. Fibreglass windows, which I mentioned have a higher R-value at the frame, are generally sold with triple glazing which is the highest performing unit available (there are some new coatings available for double glazing which claim to meet the same R-value, but have been known to be soft). A triple glazed wood or fibreglass window will greatly reduce energy loss in a home, and considering the escalating energy costs presently, will likely have a pay-back period that is a number of years, perhaps as few as 5. In other words, initial purchase cost will be substantially higher, but the return in interior comfort and energy savings will be significant.

5. Aesthetically, wood and fibreglass windows are a profound upgrade over PVC.

Overall, PVC is an inexpensive product, and you get what you pay for.

I hope this helps.

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Date/Time6/19/2012 at 11:01:39 AM

Hi Jason,

That is a very good question.

When measuring the U-Value of windows (the rate of heat transfer, the mathematical inverse of R-Values), they are usually referring to the glazing or sealed unit.

Things that can greatly increase the efficiency of a window is the number of glazings (double pane, triple pane), the Low E coating on the glass and the gas fill (usually Argon or Krypton). These gases are injected in place of atmospheric gases because they are inert and because of that they are poor conductors of heat and cold. This is only valuable while the seal is intact, so look for a quality company with a good warranty that stands behind their product.

Now to the actual frames. Vinyl is a great product and can save A LOT of money in a window package. The main issue that vinyl windows have is the expansion rate of the vinyl. Vinyl expands tremendously when heated and can become brittle when very cold. This has raised concerns over the potential for moisture and vapour laden air to get into the wall structure. I am not aware of any proof of this being an issue but it could be a concern. This concern can be addressed to a large extent through the proper installation of the window unit. Ensure that you have a seamless sill pan flashing and then wrap the entire opening with peel and stick flashing membrane (make sure it is "self sealing" as this will seal itself around the nail or screw penetrations). In addition to this, vinyl has a tendency to fade and can become brittle.

Fibreglass is quite a bit more costly but is also very low maintenance, however it is much more stable than vinyl and is very strong. Because it is made of glass fibres the expansion rate is essentially the same as the glazing it holds.

It should be noted though that a Low E coated, Argon filled glazing unit with uninsulated vinyl frame vs. uninsulated fibreglass frame have identical U-values.

If cost were not an issue (I have rarely found that to be the case), fibreglass is much stronger and more stable.

If cost is an issue, you will find that you have a lot of money left over for other items on your renovation list if you go with vinyl.

Hope this helps.


Jason Irving

The Cedarbrook Group

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Ramandeep from Fat Boy Renovation in Regina
Date/Time6/20/2012 at 2:00:23 AM

sir i been doing reno for 10yrs and i wood go with pvc any day all day pvc windows r good and its good deal i wood go with pvc

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Al in Winnipeg
Date/Time9/23/2012 at 5:53:35 PM

Pultruded fiberglass material by its very design is more stable, more durable and stronger. In general, the product has been designed and created for quality, durable installation. A limited number of manufacturers also back their product with warranties and support for the long term. Fiberglass windows may be moderately more costly but deliver substantially more value over the longer term.

Al Dueck

DUXTON Windows & Doors

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