Insulating suspended ceilings

Dear Tom:
What is the best way to insulate suspended ceilings, and what kind of
material should I use? Can I insulate these ceiling without taking the
grid work down?
Thank you. Bob Tweedie

Hi Bob,
There is no simple way to do this. Ideally, spray foam on the original
ceiling is a good way to go.
You can try putting fiberglass batts up overhead. There will be voids,
which are not desirable, but it is better than nothing.
Use the batts that are in pieces instead of rolled batts.
Tom