Affinity laws

Pick air (fans) or water (pumps), pick what you're changing, enter what the unit is doing now and the one new value. The page works out the rest with the fan and pump laws. Nothing is saved on this page.

The fan and pump laws only hold for the same fan or pump on the same system. If dampers, valves, filters, or coils change, the system curve changes and the numbers won't track. Take your readings with the system set up the way it will run, and verify with new readings after any change.