The foam that saves you $5 today (by buying the red can) will cost you $500 to fix a bowed window tomorrow. Buy the right tool for the job.

The short answer is . Using the wrong foam can bow a window frame, prevent a door from closing, or even void a product warranty.

If you have ever stood in the insulation aisle of a hardware store, you have seen the red and blue cans. You have probably asked yourself: Does it really matter which one I grab?

if you are installing, replacing, or insulating any window or door that opens, closes, or slides. Always pay the extra $2 for the blue can for fenestration work. A Pro Secret: The "Big Gap Filler" If you have a massive gap (over 1.5 inches) around a door frame, do not use either can. Buy Great Stuff Pro (gun-grade foam) with a dispensing gun. It gives you precise flow control and less waste. But for the average homeowner—stick to the blue can for windows, the red can for everything else.