Air filter guides

Everything you need to pick the right filter and stop thinking about it.

• Which MERV rating do I need?MERV 8, 11 or 13? A plain-language guide to air filter ratings and which one fits your home.
• How often should you change your air filter?Every 2 to 3 months for most homes. Here's how to tell when yours needs changing, and how to never forget.
• Air filters for wildfire smokeWhich furnace filter helps keep wildfire smoke out of your home, and how to use it.
• How to find your air filter sizeFind the size printed on your filter, understand nominal vs actual size, or measure it in a minute.