I ran across an article in the October issue of Consumer Reports on windows. They had an outside lab test the windows for wind and rain resistance, rating them accordingly. Interestingly some of the cheapest, big box store windows did the best! The prices for the cheapies were around $10 per square foot. So the question is why all the fuss in choosing windows? Is there a degree of “window snobbery” going around? I see in this forum a lot of high praise for the European and high price Canadian made windows. In light of this article it seems unwarranted.

Posted By agagent3 on 22 May 2015 11:41 AM
I ran across an article in the October issue of Consumer Reports on windows. They had an outside lab test the windows for wind and rain resistance, rating them accordingly. Interestingly some of the cheapest, big box store windows did the best! The prices for the cheapies were around $10 per square foot. So the question is why all the fuss in choosing windows? Is there a degree of “window snobbery” going around? I see in this forum a lot of high praise for the European and high price Canadian made windows. In light of this article it seems unwarranted.

All windows have to pass a test ensuring some degree of air and wind tightness. AAMA, NFRC and the two big testing agencies and certifications for residential windows. The Consumer Reports tests subjected the windows to 25 mph wind drive rain  tests and 50 mph wind tests. This is not a difficult test to pass and even the most cheapest assembled and designed window will past such a test. CR only tested the main name brand windows like Pella, Andersen, etc., and they did not test any triple pane windows out of Germany / Europe.

It's like testing a car and saying it can go 0-60mph in under 15 seconds and it can achieve 0.50 lateral G's. Pretty much any car made today, even ones with less than 100HP can pass that test. Does that mean a Chevy Spark performs like a Chevy Corvette or a Ferrari on the track? Of course not!

The CR article is not an exhaustive test of high-performance windows nor did they test the R-Values of triple pane Euro windows to dual pane big box windows. A triple pane European window like Intus is tested in a lab with 200mph winds and over 100mph wind driven rains. Intus triple pane windows are Hurricane Rated/Miami Dade County approved. Good luck with your big box store $100 windows in a high wind event.

A European triple pane window like Intus is around R6 to R7 compared to a big box store window that is R2 to maybe R3, so the Intus window is 2 to 3 times more efficient. One can attain Passive House certification with that window but would NOT attain PH certification with a big box store dual pane window.

Big box store windows will be code minimum windows in most areas. A code minimum house passes the code as allowed by law but that doesn't mean it's the wisest or best option for a high-performance home. You can build a code minimum home with code minimum windows from Home Depot but the house will not perform like a high-performance house with high-performance windows.

From what I understand the big difference between big box store windows and the high quality windows is the ability to seal out air infiltration. I found at the Canadian energy site the difference between a good window and a big box window to be .05 l/s/m2 vs. 1.95 l/s/m2. Does the added level of air tightness pay for the additional cost of the better window? Given identical 1500 sq. ft. homes in zone 6 with 10% glazing and identical U-values and SHGC what would be the difference in air exchanges per hour and the subsequent energy savings?

Interesting article here's the summary

Look at the overall scores in our window Ratings then zero in on windows that excelled at low-temperature wind resistance if your home is exposed to high winds and cold temperatures.

Consider. The Andersen 400 Series double-hung window, $310. It’s top rated among wood-framed and excelled at low-temperature wind resistance so your home won’t get drafty even when the wind howls. A CR Best Buy, the wood exterior is clad in vinyl. The Pella ProLine 450 Series was nearly as impressive and at $300 is also a CR Best Buy.The wood exterior is clad in aluminum. All casements, wood framed and vinyl, excelled at keeping out cold air and water. Take your pick. The exterior of the wood frame is clad in vinyl on the Andersen 400 Series, $400. The American Craftsman by Andersen 70 Series from Home Depot is $260 and vinyl.

For rainy climates
Need to know. Prices can vary by dealer so shop around and check manufacturer websites for specials. There are no federal tax credits planned for Energy Star-qualified windows in 2014 or 2015 but some utilities and city and state programs offer rebates or incentives to buy Energy Star windows.
Consider. The Weather Shield EnduraShield, $430, double-hung window aced our rain-resistance tests so leaks are unlikely. The wood exterior is clad in fiberglass. Among vinyl double-hung, the Simonton Pro-Finish Contractor, $260, Reliabilit 3900 Series from Lowe’s, $280, and American Craftsman by Andersen 70 Series from Home Depot, a CR Best Buy at $170, were impressive or better in our wind-resistance tests. Any casement we tested excelled in every test, including the wood-framed Pella ProLine 450 Series, $460, and the vinyl ThermaStar by Pella 20 Series from Lowe’s. It’s $310.

For warm climates
Need to know. People who live in cold, snowy areas are often jealous of you and will find ways to say unflattering things about your locale. It’s how we make it through five months of winter.
Consider. Any of the top picks are good choices for warm climates. The Reliabilt 3201 vinyl double-hung from Lowe’s is $190 and the least expensive we tested. This CR Best Buy was impressive at keeping out rain and wind without leaking when it’s warm outside.

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25 wind driven rain and 50 mph wind isn't much of a test. One thing the higher rated test numbers can tell you is that a window that will pass them will most likley be able to handle lesser values(more typical) for a longer duration. IE: they probably have more robust framing and seals that will stand up to regular use and still provide an adequate seal. Throw some of these window's performance numbers into a heat loss analysis and see what they are going to cost you in BTU's. In a well insulated house with good windows, the air infiltration losses quickly start to dominate the energy consumption numbers. For a remodel without substantially upgrading a code-built homes insulation, these windows would probably make sense. But if you are building with insulation above-code for increased energy efficiency, a leaky window will quickly cancell out the extra effort and cost in insulation...

How well will the seals and hardware withstand exposure to the elements over time? Is the window going to look ten years old in three years? Are seals and hardware replaceable?

These are all reasons why I spec a higher grade window and leave the big box windows to the fix 'n flip crowd. I've used the Pella Architect series french doors and windows in a commercial installation (mixed used office, restaurant & club) and they still perform well and look good after 15+ years.

Adding to this old thread, just had to share this line in an article.

2017
Pella vs. Andersen Windows: Point by Point Comparison
https://www.thespruce.com/pella-vs-andersen-windows-1822534

Total number of Andersen complaints are far less than Pella complaints--about 90% less.

One article I read a short time ago said save money on windows when you can, spend it on other energy saving features such as double stud walls.

That was one viewpoint anyway.

If I spend extra money on rain-screen walls and vented cavity roof, money on other items must be extracted to come out even.

Windows are at the top of the list unfortunately as it looks like easy pickings.