Depending on the filters your furnace uses, filters may need to be changed monthly or only every 4-6 months. Generally, the thicker and more expensive the filter, the longer it will last. This is because there is much more surface area for air to flow through and collect airborne particles. Thinner, less expensive filters are preferred by some HVAC technicians because they don’t impede airflow.

Here is a brief video I recorded with a few tips on keeping up with your furnace filter.