Overkill is under rated
 

Back around 2008 I bought my little dewalt fram nailer. It says on the side that it will take up to 3.5 inch nails. I thought 3.5 would be nice some times because 3 inch doesn't quite make it all the time. I would look around but I could never find 3.5 inch nails they were always 3 inch or less.
Then when I fixed the porch my parents just had built because the contractors messed it up I knew I needed to up grade my nails. They live in maine where it rains all the time so regular steel nails wouldn't cut it. They would just rust out after a few years of constantly being wet. So I got on the old ebay and looked up something to the effect of "3.5 inch stainless steel nail gun nails" and it worked it didn't bring up too many nail guns or too many loose nails. If I remember correctly 1,000 nails cost $55 shipped, its cheaper than ammo and almost as fun. I like using these in bathrooms and kitchen framing projects.
http://ecorenovator.org/forum/attach...1&d=1472330544
3.5 inch stainless steel ring shank nails.
Slight over kill for most projects.

I was putting in a bigger window in the bathroom and my wife said to make sure the 2x4 I cut through didn't shift or settle changing the shape of the window frame. I told her yeah I got this.
So I used a whole pressure treated 2x6 and most of a pressure treated 2x4 to build a header and footer around the window and nailed it all together with those stainless nails just because I wanted to.
http://ecorenovator.org/forum/attach...1&d=1472330544

Without knowing the rest of the details of your house, you really do need to reframe that window.

The way it is framed now will likely cause the header to fail. What will happen is the header will put outward pressure on the studs causing them to bow out, pulling out the nails and allowing them to bend. If you are going to forego jack studs you need to use hangers for the header. The exception to this is if the window is on the gable end on the floor directly below the attic, and the roof is framed with trusses, and the end truss is designed to allow it.

Framed properly the footer is completely unnecessary. Worse case is the sill will only carry the weight of the window, and a 2x4 on 24" on center cripples will carry that weight most of the time. I would argue that the footer and over-sized header are actually doing more harm than good. That is because they massively increase the un insulated area of the window. A small decrease in the insulated area causes an outsized effect on the total r-value of a wall. 4 Types of R-Value Typical wall construction causes about a 50% loss in whole wall r-value, and that's not even counting the R-value loss from the windows.

I agree with DEnd.

No clear structural advantage, and obvious thermal disadvantage.

Blame the wife?

-AC