Talk to your window salesperson.

I know it is possible because I have had vinyl windows mulled together on at least 3 houses that I have owned. Picture window with single hungs all ganged together, as well as 3 double hung vinyl windows mulled together. 🤷‍♀️

Every vinyl manufacturer makes a vinyl "H" mullion (probably around $40 for the piece) to mull the windows together. He is feeding you a line of BS.

I had three windows mulled together in a very inexpensive Home Depot vinyl replacement project.

I realize you are on a budget, and self labor is the cheapest option. But when it comes to important structural considerations, like joining windows, and installing them so that the rain stays out, inexperience can cause more long term costs than paying someone else to do it. Talk among yourselves, but this is not the most difficult challenge that you will face!

Minimal factory charge for mulling two windows. Let the factory do it!

Do you mean like this? These were all single units. I purposely made them wider apart but originally the builder wanted them closer together.

Factory mulled is the way to go unless the unit would be too unmanageable as a mulled set.

I have 6 vinyl double windows in my house that are mulled together. It was not expensive at all to do so, IIRC. The only issue with having windows mulled is that it creates a wider space to cover with a single window covering (blinds, shades, etc.). I don't like the look of separate shades on a double window which is why I had my triple window behind my kitchen sink set as three separate windows with trim between. It was the look I liked and I also wanted to do three separate roman shades instead of one very wide one.

Who is the "he" you refer to in your post: your husband or your contractor?

@cpartist Yes, I think so!

Are those vinyl windows with wood/hardie trim around the existing vinyl trim?

Did you have 2-2in. studs between the windows? Was there any space between the two studs? (Saw yesterday while searching around you answered this, but I can't find or remember- sorry.)

This is how far apart my husband's father, the contractor, is recommending I space minimum for strength/to save money with individual windows. I'm doing regardless right here in the basement, but trying to decide for the upstairs.

Oh my, how much experience does your FIL have because those windows are not framed correctly at all?!?!

As others have said, that isn't correct at all.

Yes mine are vinyl. My downstairs is all concrete block with wood framing between the windows. Let me see if I still have a picture.

My upstairs is 2 x 6 framing.

This is the interior opening for my upstairs studio windows. I have a triple window here.

This is my upstairs hallway and you can see how the windows are put in.

And here's a bad photo of my studio with the 3 windows put in before trimwork.

Few things:

1) Major red flags on that framing as others have indicated. Whomever did that should be fired, relative or not

2) I'm not understanding the cost savings aspect about single windows vs twin. Its two windows either way. Pretty much all vinyl windows are custom made to size these days, the only thing that could be called "stock size" is what the local box store may have on the shelf. If that is the route planned, I'd reiterate my first point.

3) With all of that said, mulling two vinyl windows together is very cheap and easy. If there is a utility channel (most vinyl windows do have), a "C" or "U" mull will snap in there to bring them together. Some others use an "H" mull that covers both edges.

@shead If you look at the window on the far right in the step down, you can see the jack studs that they are going to be adding to all the windows. They are also going back and adding all the smaller studs above and below the window. I've seen plenty of other pictures on here of the headers being sandwiched, is that just something a lot of people have gotten wrong? Is there anything else significant I'm missing? Know hardly anything about all this, thank you for concern.

@cpartist Thank you! It's hard for me to tell, but are there three studs between each of the triple windows?

They are not done framing yet that area yet. They are going to add the jack studs that you can barely see in the window on the far right in the concrete wall drop down. They've got to add the small studs/cripples above the header and below the plate once it's installed. I've seen lots of pictures on here with the header sandwiched between two studs, but not sure if that's just something a lot of people get wrong. Is there anything else super wrong after that's done? Is it just that everyone expects it to be all framed up then inserted in the wall?

@User You can see the jack in the window on the far right (in the concrete wall step down). They are going back and adding in all the plates and jacks, the small studs/cripples. Besides the header, would it be significantly wrong after all that still?

IMO if you want the view forget the grids in the windows . As for 2 windows versus one larger window IMO not a cheaper option but just have the header made for one bigger window.

Thank you! It's hard for me to tell, but are there three studs between each of the triple windows?

I believe it is 3 but can't remember. It was 5 years ago.