There are tons of window shops that do patio doors you could even check out HD. Can you post a pic of the doors so we can exactly what thye are like

Here is a picture. It is simply 4 panels with two that open from the center.

Okna doesn't do a bi-sliding door, but they can do a 12' door in a 3 panel.

Given the age of the door/ house, first check if the height of the rough opening is 68 or 70 inches (66 inch and 68 inch door heights respectively). That may limit what you can get. 

It's not a budget option, but I've had a Marvin Ultimate clad sliding door (2 panel) for around 5 years that's been great. We have lots of cold weather and snow here in MN and it seems to perform well. Their integrated screen that matches the cladding is really fantastic. You'd need to go to a Marvin dealer for pricing. They do have 4 panel doors in that line at 12ft wide.

Sorry on my earlier comment I meant 6ft8 or 7ft0in rough opening! Brain fart!

Just measured the door height is 78"

"the height of the rough opening is 68 or 70 inches (66 inch and 68 inch door heights respectively)."

Those are not door heights in any normal situation. Those would be awful short doors. Typically residential doors are 80" or 6'-8", older sliding doors used to be a bit shorter.

"Just measured the door height is 78"

What measures 78", the door panel itself?

Yes the door panels are 78"

Typical slider frame size is going to be 79" so that would work there. Swing door is usually an 82" RO.

@Windows on Washington Ltd - do you have any brand suggestions?

I drive a Toyota Matrix. I am happy, it does the job of reliably getting me from point a to point b. I don't need anything fancier, don't want something that breaks down.

This is generally my style - something middle of the road in price, function over form.

I know installation is priced differently everywhere - but could you offer a ballpark figure for replacement (4-5k, 10-12k $16-20k). I have no idea what is reasonable.

The answer to your pricing question: Yes.

Those ballpark ranges could all be accurate depending on what you are looking for. The good news is that even your low end is realistic so you won't get sticker shock.

If you don't need a center opening that clears the width of two panels, Okna is a nice option right in your PA back yard. Excellent door in 3 or 4 panels. As also already mentioned, Softlite and Sunrise make very nice sliding doors in vinyl. Andersen and Marvin make nice doors as well, but you'll step up into that next price tier and the performance (u value and air leakage) typically drop a bit as you sacrifice some efficeincy for looks. All depends on your priorities.

What he said.

Thank you all for the guidance.

I think the current design fits with the symmetry of the room, so I will probably stick with that layout, but will need to compare some of the above suggested windows.

If I understand correctly Softlite and Sunrise are the top contenders, Andersen and Marvin pricier and less efficient. Paying more for aesthetics rather than functionality/performance.

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20' x 20' with the 12' sliding glass door on one side and the 10' fireplace on the opposite side with 5' openings on each side of the fireplace leading to the foyer.

8' wide 5' tall window on the other side of the fireplace

What about your other sliding glass door on the left? If you have one that is going/leaky/loose, the other one is not far behind. It is more cost-effective to replace both at the same time if you can, than to replace them individually with the second one in the future. Just giving a heads up.

@Jennifer Hogan , yep, sounds like you are on the right track. The only thing that I'd clarify is that the Okna door (and some others with similar offerings) wouldn't change your symmetry. You can still get a 12', four-panel door. It would simply have one operating panel (or two with a mull-post in the center) as opposed to a clear opening "two panels wide" in the center.... hopefully I'm explaining that well. Maybe that is relevant to you or maybe not, I just wanted to clarify.

https://www.weathershield.com/

Thank you, that helped!

Anyone allow me to ask if there's any feature of large glass door [installation] that decrease traffic noise? Thank you.

Heavier, i.e. thicker, glass to start with. Laminated if you want to break the bank.

Air tight door will help as well.

Good thread. May I ask if which company can make a 12" X 80" 4 panel patio door in black (the center panels should open) with a good warranty for the door finish? I live in hot Phoenix, Arizona and the doors will face East. I have Pella Impervia windows on order in black. Thanks!

Don Young in all aluminum maybe?

We replaced all our ca. 1980 windows and doors and were concerned about sliding doors; I just think of them as always off track and flimsy. Western was recommended to us and we're very happy with them. The sliders are great quality and slide easily. We decided to stick with one opening and two stationary panels for our largest space. To upgrade to a door that stacked was 3x the cost.

In this pic, the center frame looks weird because the screen door isn't perfectly closed. But all the frames are the same thickness.

@stiley The doors look beautiful in your home! Pictures are so helpful! Thank you. @millworkman I have never heard of Don Young. I will look and see if they service the Phoenix area. Thank you.

Just scrolling through…and thought i would mention an idea…staining the concrete patio can add a nicer look to your outdoor area

@btydrvn - just got a recommendation this morning for someone to do some repair work on the older cement slab and find out what we can do to make the whole slab look nicer without breaking the bank.

Staining is a simple process…just spread it around with a broom…on a clean surface…it comes out mottled…so it doesn’t have to be kept perfectly clean to look nice…and any color is prettier than concrete gray…we used an indoor stain in our home…unfortunately the green is the only color you can’t use outdoors. 🤷🏼‍♀️

And ,of course outdoor rugs are a great addition…defining seating areas and making it all more inviting

Update - After talking with the local lumber yard that sells most of the sliding glass doors to our local contractors, contacting the brands mentioned above and getting 4 estimates I have finally ordered my new door! Estimates ran from $5k for a substandard product that a local window company tried to convince me was as good as any of the other brands, but substantially lower priced. ( VyWinco didn't have such hot reviews) to 16k for an Anderson 200 series door.

Funny thing is, I ended up with an Anderson 200 series door but from a GC/builder vs a windows only shop. He quoted me 8k for the same door as the 16k door. The local Softlite contact told me they no longer make a 4 panel door and recommended Paragigm. Reviews seemed to suggest that they were great doors, but were sold and the quality suffered. That estimate was over 7k and I wasn't going to take a chance for less than $1k in savings.

I felt very comfortable with the GC, who measured things, discussed options, researched a few different doors including Marvin and recommended the Anderson door. He pointed out the other other door that I have is the same as the one he is recommending and the two will match. I like the other door (now 15 years old with no issues).

If he does good work I may hire him for other projects.

Thank you to everyone who helped me make this decision.