Options for LARGE windows (vinyl/fiberglass/durability/cost)

[ViS]

I’ve been reading these forums for weeks and found a ton on invaluable info here. I’m starting a new thread because I seem to have a somewhat uncommon situation. I’m looking to replace original (from the 80s) aluminum sliders many of which are rather large, including a few 6’ tall (ex: 4x6’, 5x6’, 6x6’) and a few 4’ tall (ex: 6’x4’, 5’x4’). I would like to get something with a slim profile to maximize glass area and maintain the streamlined appearance. One issue I’m encountering is that many manufacturers don’t seem to offer windows in sizes I need. I’m looking at vinyl and fiberglass (don’t care for wood) and after much research and back and forth with local dealers (I’m just north of NYC) currently pursuing the following options:
- Okna 800 (custom engendered for 6’ high units as their “standard” options are only up to 68”)
- Sunrise Vanguard
- Marvin Integrity/Infinity (Integrity sliders are not available in 6’ heights)

What are you thoughts on windows of this size? I have no issues with vinyl generically speaking but is it durable enough to perform long term in a 6’x6’ window, even if it’s one of the better designed windows? Will I get anywhere close to listed performance parameters (insulation and especially infiltration) in sliders of that size? A few of the tall windows have to stay as sliders due to location but I can potentially switch others to casements (assuming they are available in my widths)… Would it be a good idea for performance reasons?

I’m also getting cost estimates that are so all over the place (ex: $800-$2400 with anything in between for a single 5’x6’ installed) that I have no idea what can be considered reasonable. What do you think would be a reasonable labor cost per one of my large openings? It’s a 2x4 construction with wood siding/casing and no interior trim (drywall returns).

Thanks much!

[TheWindowNerd]

The Okna 800 would be my first choice. The Sunrise Vanguard my second choice.
If I was going to look at fiberglass I would suggest InLine fiberglass.

I would expect to get the basic performance as shown in test.
AS with most windows, installation is critical for performance and durability. Sliders need to be properly supported along the bottom tract both on the inside and outside of the window. Typically hard to support outside edge with out some sort of angle or trim board.

Cost is tuff to comment on, I do not have the product specs, the install specs, nor a site visit to evaluate properly.