On Apr 24, 12:49 am, John Keith wrote:

snip

The frames are metal (these are old windows)
so there is only a very small surface to apply any weatherstrip and
the gap is very small (but large enough to be a source of air leaks.)

With metal frames and probably single pane glass you're fighting a
losing battle to save energy. IMO the people would be far better off
with a modern window that doesn't leak, doesn't transmit as much
summer heat, doesn't lose all that heat in winter and can be opened
now and then to enjoy a nice breeze. Factor in an energy credit on the
replacement cost and the choice is easy. HTH

Joe