Ask the dealer or find out the glass packages they offer and and look up the glass performance.

You can sort through their downloads section as well. They've made it inordinately more cumbersome to sort through.

https://www.simonton.com/product-downloads/#

If you are digging this deep into thermal ratings . (which I commend!), let me speed this along for you and advise that you may want to choose a different product. You'll find mostly mediocrity here.

@fridge2020 would you care to explain?

@millworkman what is high quality these days? I'm having trouble with Simonton (eg: getting the data I want). My suppliers have some of the normal brands (eg: Pella, Andersons).

New construction or replacement? Double Hung, Casements, etc., etc.? What do you want the window to look like on the exterior and interior (wood etc.)? Simonton is vinyl is that what you are looking at. The better vinyl brands are regional, what area of the country?

@millworkman Replacement / Double Hung and Casements. I live in WV (NoVA area, closer to Maryland / VA / DC).

Call Eric at Windows on Washington his info is on many posts here on this forum. He will steer you in the right direction for sure.

+1 to all of the above.

While you could do worse than Simonton, its a pretty dated product, the thermal and structural performance ratings are not on the high end, and as MWM alluded to, this was all true before being taken over by a mega-company like plygem. In my experience that type of change usually sees an emphasis on improving the profitability of a line as opposed to innovation or improvement.

The good news is that it sounds like Windows on Washinton is nearby. They are one of the best in the business, and the Okna window line is ELITE.

WoW doesn't serve this area.

I am sure he could recommend someone local to you as he is more familiar with the area than with HomeSealed, or myself.

Feel free to shoot me an email you want to. We can chat offline.

Enovotny at the URL is my email.