Trace and Cut Your Holes
Place your fan and PVC elbow on top of your cooler lid to eyeball the spacing. Do your best to center these items front to back.
The more symmetrical and finished the final result looks, the more you’ll probably use it.
Using a construction pencil or marker, trace the circumference of your fan’s cage on the top of your cooler’s lid. Bear in mind that you want the fan to fit as snug as possible without falling through the hole.
Next, trace the circumference of the PVC elbow you’ve selected beside the fan.
Use a drill to cut a starter hole along your guidelines, then use a jigsaw to make your cuts.
Assemble Your DIY A/C
Set you fan in its new home, forcing air into the cooler. Place the PVC elbow in it’s cut-out; you may want to glue it in place.