So bloody hot right now, how could I be talking about insulation?  Proper insulation in your home will help your house to stay cooler inside in the summertime as well as stay warm in the winter.  For a house heated by gas or oil in this area (Ohio) these are the recommended levels:

Most older homes have between 3" and 6" of fiber glass blanket insulation. This is roughly equal to an R-value between R-9 and R-19.

Attic ceiling
R-49

Cathedral ceiling
R-38

Walls
Sheathing: R-5
Cavity: R-13

Floors
R-25

Crawlspace
R-19

Basement
Exterior Walls
R-12

Slab edge
R-8  

Basement
Interior Walls
R-11