The SFP is a parameter defined as the supply and exhaust fan summed electrical output. The value includes only the electricity that is used to move the air where in addition to possible electricity to such warm air to come.
The lower the value the better the SFP uses the fan electrical energy to move the air igeonm ventilation system
The flow SFP is calculated as atomized the maximum design flow for the fan.
The electrical power needed to operate the fan at the current design flow for the fan.