CFM stands for cubic feet per minute and it is a measure of the airflow rate in an HVAC (heating, ventilation and air conditioning) system. The optimal CFM range for residential HVAC furnaces will vary depending on the size of the home and the heating and cooling needs. In general, the optimal CFM range for a residential HVAC furnace is between 300-450 CFM per ton of cooling. This range will ensure that your HVAC system is properly circulating air throughout your home, which is crucial for maintaining good indoor air quality, ensuring proper temperature regulation and overall home comfort.

When the CFM is too low, it can result in inadequate heating and cooling, as well as poor air circulation in your home. This can lead to rooms that are too hot or too cold, as well as poor indoor air quality. On the other hand, when the CFM is too high, it can lead to increased energy consumption, higher energy bills, and potentially damage to your HVAC system.

It's important to note that other factors such as the size of your home, the number of rooms, and the number of windows, will all impact the optimal CFM range for your HVAC system. It's important to consult with a professional HVAC contractor, to determine the optimal CFM range for your home, and to make sure that your HVAC system is working efficiently and effectively.

Improper function of your HVAC equipment can contribute to suboptimal CFM performance. One of the most common culprits are dirty air filters. It's very common for homeowners to remember to replace dirty furnace / air filters and when they clog with dust and debris, the airflow CFM reduces as its more constricted. On average, air filters last 3 months. Some deeper pleated ones may last up to 6 months, and cheaper fiberglass or cut-to-fit options usually only last a month. Washable filters often last 2-4 months in between washes, but again depends on use and homeowners may find they last longer when the system runs less in spring or fall, if you're in a four-season climate.