When calculating the pressure drops of a fan it’s important to take in consideration the reference air density as displayed in the fan’s datasheet. Sometimes this parameter is not displaied, but usually it’s 1.2 kg/m³. Why this parameter is so important? Because the fan curves have to be fixed accordingly to the air density of the project. Coils does this calculation automatically. Here’s an explicative example:

As you can see, the reference air density of the fan is 1.2 kg/m³ and Coils calculate 1.378 kg/m³ of air density. Coils fixes the fan curve accordingly to the ratio between the two air densities, changing accordingly the balance point too. This makes the calculation results of Coils even more reliable.