How many panels does a two-car garage door need?

A standard two-car door is about 16 feet wide and 7 to 8 feet tall, so you need roughly seven to eight 24-inch by 16-foot panels to cover the inside face. Buy one panel per door section width and plan for the full height.

Does R8 mean the whole door becomes R8?

No. The R8 rating applies to the panel itself. The door's final performance depends on the door material, gaps, and how well the panels are sealed at the edges.

Can I cut it to fit door panels and windows?

Yes. The foam core cuts with a sharp utility knife against a straight edge. Score the foil first, then cut through the foam, and seal cut edges with foil tape.

How does it attach to a garage door?

Most owners use double-sided construction adhesive, foil tape, or mechanical fasteners through the panel into the door frame. It is light, so tape alone holds on a clean, dry surface.

Is it better than rigid foam board?

Rigid foam board gives more bulk R-value per inch and resists dents better. This reflective panel is thinner, easier to cut, and better at blocking radiant heat, which matters most on sun-facing doors.