Never heard of them. Will se if I can look at their site this evening maybe.

I had never heard of GLA before reading your question, but I was curious so I looked them up.

German company who makes two window styles - fixed and tilt/turn - which is pretty common among European window manufacturers versus some North American window companies that might manufacture as many as 10 or more different styles.

I am not suggesting that one manufacturing philosophy is better than the other, only different.

One thing I did notice when looking through the GLA website was the NFRC logo. This hopefully meaning that they certified to NFRC standards rather than presenting translated European energy performance values as North American imperial measurements to use as a comparison with North American windows. And therein lies a problem, as I see it.

They are listed in the NFRC website (surprisingly not all companies who have the NFRC logo on their website are), and they do have very respectable performance values listed for their windows there, so that's a big plus to me.

Unfortunately they also advertise performance values on their website using imperial measurements with values that are slightly to substantially better than what's shown on the NFRC website, suggesting that while the company is NFRC certified they appear to be using translated Euro test data on the website to present performance statistics that display better performance values than what they really are.

IMO that's either very sloppy or dishonest, and that would be a huge red flag regarding this company if I was considering them, however that doesn't mean that they make a bad window or are a bad company to deal with.

I am a bit OCD concerning European window performance claims versus North American and reality.

Oh wow! I really appreciate the time you took for this helpful response. Thank you!

You're welcome, and I am glad that it was helpful.

Hi Greg! I'm curious. In your experience, who WOULD be a good european windows provider? I'm in the market myself and I'm looking at GLA, EAS, Broga and Neuffer so far. I'm in the southeast, so delivery might be a thing. Any suggestions?

Any particular reason why you want a European manufacturer rather than North American?

There are a number of companies in US and Canada that make tilt/turns that are pretty much the same as anything coming out of Europe.

I only know about Pella and Marvin… and i hear Marvin is discontinuing their line. who else is there?