Window issues here

How can I find out if a window has the corecct R-rating the manufacture is claiming? A client of mine feels his new windows are not doing the efficient job he is expecting them to do. He has installed commercial grade baked on primer aluminum double pain windows. I have not seen them or confirmed his complaint yet. But would like to be able to know if the R-value is correct on them. Thank people ahead of time for any remarks.:mrgreen:

I don’t think they rate windows in “R Value” anymore.
Is this really what you want to know?

You can measure heat transfer and convert to an R-Value.
What kind of temperature measurement equipment to you have accessible?

The ratings they advertise is done in a lab so your readings will not match.

Heat transfer through windows occurs through conduction, convection and radiation.
R-Value will only address the conduction part.

The clients problem may be because of the others as well.

What is your plan?

Why not advise him to call the manufacture of the windows for any questions about them?

Aluminum frame windows are horribly inefficient regardles of whatever magical glass is installed. I did a home last weeks where the interior of the frames were 105 degrees with the morning sun on them. It was 80 degrees outside.

Kewl tewl Brian…and only $799!

I know, but it is cool.

Get a backup…

Try to educate your client to the fact that heating performance is a whole house as system question. Not just one minor detail of one specific part. I doubt strongly that the U-value of the windows is the real culprit in any case. Look to the whole system.

What R-value (U-value) was he told the windows were? The point about commercial windows doesn’t impress me. In my experience they are designed for different requirements then residential windows. Often of higher concern is the maintenance needs which is why aluminum is a popular case material.

Let us know how it comes ouit. With pics please.

I had a sunroom once with high end aluminum frame windows, they had thermal breaks designed into the frames where no metal to metal connection existed from outside to inside. Some kind of cool glass too with 21 coats of silver and titanium with argon gas.

Geesh, LowE 1, 2 or 3… U Factors, Solar Heat Gain and more. Several factors are there when ordering a window (not to mention AHJ has minimum standards too). The windows likely had a rating for these on the glass when purchased and could be looked at.

Generally you get what you pay for… cheap clear glass unit installed into even a nice window frame can make it a lil warm.