How do I make my windows warmer without losing the light?

The bpx stores carry clear plastic that you can use. I think the brand i used was frost king, but not sure.We had a whole wall of windows in NY and i used it .you can see thru it and not know it is there, unless you bump your head on it,while applying. you apply it with tape, then shrink wrap it with a hair dryer, simple and effective. And I did bump my head, often, before I remembered it was there. perfect vision.good luck!

Home depot sells window insulations kits by Three M

I made a storm window for the inside. The window was recessed about 4" from the surface of the wall. I carefully measured the box area where the window sat, went to the big box hardware store and had a piece of plexiglass cut 1/4" smaller than than the measurement. Then used a foam rubber edging all around the edge (KidKushion).

And because it was 4'w x 6'h and I had to handle it myself, I installed a handle near the bottom. Drilled 2 holes about 4 inches apart and 3" from the bottom, used 2 screws & bolts plus 4 washers and a piece of webbing as the handle from an old beach bag.

It fit perfectly and during the winter it saved me heating money. And it made it a lot more comfortable sitting near the window at my desk in my home office.

We have long windows and last winter I used bubble wrap....and was surprised at the results. Cut the wrap a little longer than your window to cover past the glass onto the framing. Hang strips vertically. Mist the window with water from a squirt bottle and then position your strips of wrap onto the window. (flat side against the glass) Then align the second strip overlapping the first an inch or so. Repeat until window is covered. When cold weather passes just roll up and store or give to grandkids for a bubble party!!!