Over the past 15 years of construction, my practice has been to refrain from using plastic or vinyl windows in insulated structures. My opinion on the disposable aspect of plastic/vinyl windows was confirmed in a late '07 Consumer Report study. Plastic/vinyl windows do not provide longevity in performance ratings once exposed to the environment. Wood remains the most practical material for window construction. Adding an exterior cladding also adds low-maintenance benefits to the wood construction. I would suggest that the lowest quality wood window would still provide at least twice the long-term benefits in energy efficiency over the highest quality plastic/vinyl window. In regards to your comment on the removal of the exterior siding in order to add insulation, this would be the ideal time to purchase the best window within your budget. Generally, the major expense involved in window replacements (i.e. retro-fitting) is "custom sized" replacements, or the labor involved in retro-fitting new "standard sizes". If you elect to install a disposable window today, it will cost you a lot more in 5-10 years when you have to replace/retro-fit replacement windows within your "new" walls. Regarding your question on sizing, double hung window sashes generally operate more effortlessly when the width-to-height ratio is at least equal, or the height dimension greater than the width (per sash). However, I don't believe that you would have any energy performance issues. Lastly, keep in mind that both window products you reference utilize a large percentage of plastic within the window construction, and plastic = disposable. There are likely many other window dealers in your area that can provide all wood windows or wood windows that utilize a metal cladding, which will far outlast plastic construction.

Truly enjoying this conversation, thanks for all the info. I have large windows, a few are 83" and two are 96" high. My options are limited due to that size... I am planning to change all of them, ~18 windows damaged post hurricane Ida. Got multiple quotes, I was between JeldWen V-4500; Simonton 6500, and MI 5200. I am also looking into PGT option. But like many above, the very experienced contractor is recommending MI6200... Will probably not consider it after all above.

The question is...does it matter? I think it does, because words matter. We throw around words on this board constantly when we really mean other things, and I too am guilty of this. Custom really doesn't mean custom when used on this board, it means architect. So someone who maybe isn't experienced on this board may see the word "custom" and think they designed their house from the ground up, therefore it is very custom. When most posters really mean the house needs someone with professional design experience and some measure of talent to guide you through the design process or actually design the home. ----------- Also a better understanding of the differentiation can lead to better advice. In the area I was born in (an area that I still own land in), the major tract builder can build a 4,000 square foot house for under $280,000. If you can't differentiate between a tract and production builder, it is hard to understand how that is possible. ----------- Finally, I am not sure this board does a great job these days of helping people build a home. I might be alone in this, but I would prefer a well built, poorly designed home over a poorly built, well designed home. We focus so much on the design process and the freedom you have to make selections that we sometimes miss the real tragedy of production and tract builders, the shortcuts they take in construction in order to deliver those appealing prices. While I agree custom homes are better than semi-custom and semi-custom is better than production, etc., the real quality cutoff for me is control of the how the walls are built rather than where they are built. For me this is the biggest draw for an architect and the thing rarely touched on, but may actually pay dividends far into the future that make architects not only affordable, but profitable for those value conscious consumers. Again, this is just my opinion.

Builder Bob, you seem to have a real bone to pick with okna for some reason, that seems to be clouding your judgement. Looks like homeseald laid the ratings out above, I cant really say much more besides those facts. Makes no difference to me, but I think the vast majority of people disagree with you. You should probably stick to building stuff and leave windows to the window guys. Cut rate builders are probably the only guys that would like a cut rate product. Best of luck my friend. It will be interesting to read back through this in a couple of years if they are still around. Your posts kind of sound like you are trying to make this an advertisement for vytex, but you forgot its not that great of a window: