What Does CFM Stand For In HVAC? It’s All About Airflow

CFMs. If you have been looking at the specs sheets of HVAC devices (ACs, furnaces, dehumidifiers, air purifiers, and so on) you have probably come across a unit labeled as CFM. What does CFM stand for in HVAC?

In HVAC, CFM stands for Cubic Feet Per Minute. It is a standard unit of airflow volume. It tells you the volume of air that is being moved by an HVAC device every minute.

Example: A 2-ton mini split AC unit generates 800 CFM. What does that mean? Well, it simply means that such an air conditioner will blow 800 cubic feet of air out of the indoor air handlers. CFMs are basically a measure of what volumetric quantity of air is being moved every minute in cubic feet.

Why Does CFM Matter In HVAC?

CFMs do matter quite a lot. Namely, every HVAC device from the air conditioner to furnace and air purifier has to move air. This is the only way how an air conditioner can cool a space – by moving many CFMs of cold air, the furnace can heat a space – by moving many CFMs of warm air, and an air purifier can deliver the clean air back into your home.

If these HVAC devices cannot move air effectively (problem of lower-than-required CFMs), you will get hot spots or spots with unventilated air.

Example: As a general rule, you will need about 400 CFM airflow per ton of cooling. If you were to have a 2-ton air conditioner with only let’s say 300 CFM (while you would generally need 600 CFM), the AC unit will have quite a lot of cooling power but that cool air will not be adequately moved throughout the rooms. What you get is that some rooms are cold but other rooms are hot; we talk about uneven or heterogeneous temperature distribution.

All in all, when checking the HVAC device specs, it’s quite useful to know what CFM actually stands for and have an idea of how many CFM you would need.

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