What is the Most Common Furnace Filter Size?

When it comes to furnace filters, the size is determined by three-part dimensions. The first number is the length, the second is the width, and the third is the depth or thickness. To make sure you get the right filter for your home, it's important to understand more about furnace and air conditioning filter sizes. The main purpose of a furnace filter is to protect the blower fan from dust, hair, and other debris that is carried through the return duct.

To be safe, you should check with your furnace manufacturer to see what the maximum MERV rating is that your model can use. If your HVAC system uses a whole-house filter (which is usually located near your central furnace or air conditioning unit), you'll likely see a model number instead of dimensions. To ensure you find the perfect size for your home, watch the video for guidance on using the furnace filter size chart and hear expert advice on making the right choice and avoiding common mistakes. It's best to confirm what your MERV rating converts to in order to make sure you're using a safe filter for your furnace.

However, to maintain its optimum performance and help prevent possible malfunctions, it's necessary to change or clean the furnace filter regularly.