Most of the window companies offer Aluminum framed windows.
they are truly a bad choice
Aluminum frames cannot insulate as well as vinyl, wood, or fiberglass frames.
its very conductive material.
Aluminum conducts heat better than any other building material. And that’s very bad for the performance of the window, even if the frame profile is simple and compact.
aluminum frames can easily become cold in winter and hot in summer creating a
thermal bridge
vinyl, fiberglass or wood frames are far better choices
So why don't the contractors offer that option, it takes more skilled workmanship to install them and vinyl, fiberglass or wood costs 10-15% more so to keep their price quote lower they offer aluminum.
Also aluminum is quick to install the frame is simple square cuts low skill requirements to install.
They also push sliders as a good option, it will allow you to open up the lanai when it's hot. But that at most is 50% open. What about air leakage when its cool or cold, sliders are one of the worst.
Also think about how many vertical window frame bars block your view when open or closed ... not so nice.
A much better choice is a fixed window (picture ) with an awning window above or below or both
these seal very well and are available at HD or Lowes, in energy efficient frames with Low e 366 glass. about $300.
that will give you all the ventilation and not block your view as much as sliders for sure.
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