In a mixed humid climate, insulating the ceiling of a basement is a waste of money. It will also cause you to spend more money than you should on monthly heating and cooling bills.
In this photo, you see a nice insulation installation in a moderate priced home. You also see a walk out basement wall with no insulation. In this particular project, the builder could have saved money by adding one air vent into this basement space from the HVAC system and insulating the back wall and NOT insulating the ceiling above. This would not only have saved him money, and would have reduced the home owners monthly electric bills.
Fiberglass insulation installed in the ceiling of a basement is pulled away from the floor system by gravity. If it is not in contact with the warm surface above, it is not performing any function. To combat this, many builders install wires to hold the insulation in place – crushing the insulation. Fiberglass insulation is only effective when it is fluffy and full of air, if you smash it, you might as well not use it.
Proper insulation techniques and an understanding of basic building science elements will save the builder money and the home owner money. Build it right the first time and we all benefit.