Windows in a door? In addition to the practical points listed by mark_1, a windowed door is generally better looking. And much friendlier.
It’s similar to the difference between a store front with plate glass windows, and a store front with barred windows. The bars may be practical, or even necessary, but if you can leave them off it makes the world seem nicer.
To some people, I imagine that a front door, with no window, which is not inviting nor friendly, is a feature, not a bug.
That’s what peepholes are for.
To me, a door is there to protect my security and privacy. Putting a big hole in it kind of defeats its purpose.
Yeah, in my neighborhood in Chicago, I’d guess at least 80% of people have windows in their doors. I’ve not done a formal survey, but stepping out the front door and looking at ten houses across the street, that seems about right. Our house has a one foot by one foot window. The house directly across the street has a larger one, maybe 1.5 feet by 2.5-3 feet. The more serious security weakness for our house would be our rear sliding porch door, which is mostly glass, so like 2 feet by 6 feet. I’ve owned both a pitbull and now have a rottweiler-pitbull mix, so I’m not too worried.
Do you have the same concern about windows in your walls?
My windows are 30” above ground level, so…
But yeah, I kind of forgot that houses exist. Sorry about that.
30 inches, or 30 feet?
10 meters.
The biggest weakness of windows in doors, as seen in innumerable crime dramas, is the thief breaking the window and reaching in to unlock the door from the inside. There are plastic sheets (not unlike screen protectors on phones and tablets) that will make the process much more difficult. (Recall the video of the fellow breaking into Nancy Pelosi’s house, even with an axe and French doors, it took him almost a minute to get through)
As a resident of the Great White North, I don’t think you can even buy a steel exterior door that is not insulated in Canada. The construction standards people have had a fetish about proper insulation for decades - R2000 and all that. And none of the steel doors I’ve encountered are thin steel flimsy enough to make me think they would be susceptible to an old-fashioned can opener.
I suppose my solution to the OP would have been to take off the door, and cut out the top and bottom wood pieces - I assume the door is two sheets of steel on a wood frame. So make a hole about a foot or two wide top and bottom, plenty of room to use a tool to remove any flimsy bracing, then progressively fill with foam or pellets. (There is also low-expansion foam, or add foam slowly a layer at a time so you don’t have massive expansion with nowhere to go). Then glue in replacement wood pieces and you’re done.
By the time you do all this work, it’s probably cheaper to buy a new door.
One final consideration is that an insulated steel door has a thermal break all around the edges. There is the outside panel that wraps about half way around the edges and a similar interior panel. The two do not touch on the edges. So even if you insulate the door at what seems like a lot of work it will still be cold on the inside panel.