insulation

[jayjay]

Any thoughts would be great.
I have an old 2000 sf homemade cooler. 2x4 walls with 2" rigid ins inbetween and a drop ceiling of glasstec(1/8" layer of hard fiberglass) concrete floor. The whole thing is in bad shape leaking everywhere.
Is it worth installing some insulation in the drop ceiling(maybe 1" fiberglass)
Would I notice a differance this summer? Might cost about $1,000 (us) My electric bill more then triples in the summer.
In other words where should I try and install insulation?
My cooling guy says insulate around the base of the walls cause thats where all the cold air is.
My thinking is try and go for a sealed up room.
Please help.

[Sridhar1312]

How many years old? If it is more than 7 to 10 years it is better to replace as the insulation material looses it s property due to aging

[jayjay]

thanks for responding.
The unit is at least 20 years old. I can't even come close to replacing the unit at this time. Not enough$$
I was trying to put what little money have to the best use. Is it worth trying to seal up the ceiling or adding more insulation to the base of the walls. The ceiling has no insulation as it is.