The best way to insulate a drop ceiling is to install batt insulation between the ceiling joists before installing the hanging grid.
Putting insulation in ceiling.
Always cover the tops of the ceiling joists to make sure the insulation is deep enough to reach your target r value and to prevent thermal bridging the heat loss that occurs through the wood framing.
If you don t put the insulation around the back the pipe could freeze in the wall.
Rushed installation of insulation materials can block grills and vents that move air throughout your house.
Work from the perimeter of the attic toward the door or hatch so that you don t trample all over the insulation you just put in.
If you are seeking to add insulation to a suspended ceiling that is already in place however you will have to rest the batt insulation on top of.
If you don t have an attic however there is.
When installing any type of insulation make sure that your contractor and his team don t cover up access points to your home s ventilation system.
This installation would proceed as any insulation installation.
So i suggest you put your time and money into improvements that have a bigger payback such as adding more insulation in the attic weatherstripping your windows and doors sealing cracks insulating the rim.
How to put insulation in a ceiling before drywall.