I used to switch to incandescent desk lamps in the winter (and back to LED in the summer) to help keep my hands warm on the keyboard.  Then Congress unconstitutionally outlawed manufacture of incandescent bulbs and washing machines around 2010.   (Only "High Efficiency" washers are allowed, which makes sense in water scarce places like SoCal or AZ, but for people by rivers just means your clothes don't get clean.  Yes, I've developed workarounds.)   

For a while, a German company offered "indoor electric space heaters" that screw into a light socket and emit visible light as a by product.  I loved these, but either not enough customers got the joke, or govt types didn't think it was funny.  I haven't seen any replacements.   I've tried laying a scarf over my hands, but although I can touch type, my fingers would get misaligned reaching for function keys, PgUp, arrow keys, mouse, etc.  (Not a problem with vi/vim.  Which is why vim is still my editor of choice.)