Check your attic insulation against ENERGY STAR's R-value chart
Added
Measure how many inches of insulation are in your attic, find your climate zone, and compare with ENERGY STAR's recommended levels before you buy or blow in more. Higher R-values resist heat flow better. Check the source for your zone and wall, floor and crawlspace guidance.
The result
Result: ENERGY STAR (based on the 2021 IECC): for zones 4A and 4B, add attic insulation to R60 if the attic is uninsulated, or R49 if it already has 3-4 inches.
Note: Wear a mask, gloves and eye protection in the attic, step only on joists, and watch for wiring. Hire a pro if you're unsure.
Source
ENERGY STAR: Recommended Home Insulation R-Values (opens the original source in a new tab). Check it for the latest numbers before you act.