Windows permit light to enter living spaces.
That’s where you could have either a reflective tubing through the roof or a sky window.
so do obscured skylights. next.
We’re currently starting to build a house. Windows will be 14 inches wide and 36 inches tall. Not many of them.
Most people put in big windows and then cover them in drapes. Sure you can let in sunlight and a little warmth but there is a net loss on cold coming through the windows.
With LED’s providing light compared to the old days of kerosene lanterns why bother with a heat losing hole in your house? My shop is 50’X 60’ and no windows. There are 10 8 ft LEDs in there which is bright as daylight.
Some zoning areas mandate a window big enough to get out of. in case of fire. For some of us that would have to be a BIG window. Which makes a nice entrance for bag guys.