Blower size vs evaporator size

"To accurately measure the performance of a system or use the charging data accurately, you must measure the amount of air passing across the evaporator coil. The airflow is measured in cubic feet per minute (CFM). 350 to 400 CFM per ton of cooling is required for proper air conditioning system operation. For example, if you are checking a 3 ton system, the air flow required is between 1050 and 1200 CFM." So normally, an entire system will include furnace, evaporator and condenser. "

Evaporator and condenser normally match up using tonnage, that part is easy. But what size of furnace should match up with your evaporator?

It makes things a bit confusing because the BTU of furnace do not really match up with either evaporator or condenser tonnage. The reason why the size of the furnace is relevant and important is because furnace blower will be shared during both heating and cooling. So after you figured out the right size of AC, it is important to know the required blower size, the estimate of 350 to 400 CFM per ton seems a good number to use.

High speed is what the system usually runs in, when in the cooling mode.

This article seems very helpful.
https://www.hvactrainingsolutions.net/airflow-calculation/

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