When your furnace filter slot has rails at the top ... and some of its models last up to a year before needing replacement.

We also calculate the annual costs of replacement filters, based on the manufacturers’ recommendation for when to change them. (Keep in mind that prices may vary by retailer and that it may be ...

While replacing the air filter or scheduling a professional ... it's a smart idea to plan for a replacement. When a furnace operates properly, it generates heat and disperses it evenly throughout ...

One of the most common mistakes people make while doing this chore is putting in the new replacement filter backward. For more on gas furnaces, see our gas furnace brand reliability and buying guide.