Even though it is technically possible to operate a furnace without an air filter, it is not recommended. Doing so can cause serious damage to the system and the health of your family. At most, you can run it for two days without a filter, but the preferred option is to run it with a filter for at least one day. The air filter plays an integral role in the successful and continuous operation of your furnace.
It is in place to improve the overall air quality in your home, but it also helps protect and extend the life of your system. Without a filter, dust and debris can get stuck in your system and cause a large build up over time. This build-up can clog and damage the system, leading to decreased airflow and costly repairs. In addition to all the problems you can cause with your HVAC, not running your furnace with a filter can also increase allergies and household dust.
Filters are made of tightly woven materials that trap any contaminants and particles as they pass through the system, which means those contaminants are prevented from entering the interior of your furnace and inside your home. When it comes to the care and maintenance of your HVAC system, monitoring your air filter is the best thing you can do. Even though they seem like a relatively simple component, the air filter can cause your furnace costs to increase. Contrary to popular belief, the first and foremost purpose of an air filter is to protect your HVAC equipment.
Without a filter, you and your family breathe in indoor air pollutants or leave them behind to create a buildup in the oven or duct network. Running a furnace without a filter exposes it to poor air quality, fire hazards, costly repairs, and possibly a broken furnace. To protect and extend the life of your system, we recommend that you only operate the furnace with an air filter. Servicing the oven filter and changing it every 1-3 months will help avoid system failure.