Fan System Pressure Loss Calculator
Total system pressure loss a fan must overcome across components.
Enter your values
Enter the filter loss in in wc.
Enter the coil loss in in wc.
Enter the duct friction loss in in wc.
Enter the fittings loss in in wc.
Enter the other accessories loss in in wc.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Total system static pressure
- 1.6 in wc
- Select fan at (+15% margin)
- 1.84 in wc
- Largest contributor
- duct
Quick answer
Total fan system pressure loss is the sum of the pressure drops across every filter, coil, duct run, fitting and accessory in the airstream.
SP_total = sum of all component pressure drops
At a glance
| What it does | Total system pressure loss a fan must overcome across components. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Filter loss, Coil loss, Duct friction loss, Fittings loss, Other accessories loss |
| Main output | Total system static pressure |
| Formula | SP_total = sum of all component pressure drops |
| Cost | Free — no sign-up, no download |
How to use the Fan System Pressure Loss Calculator
- 1List the pressure drop across each component in the airstream: filters, coils, duct friction, fittings and any accessories.
- 2Sum them to get total system static pressure.
- 3Select the fan at this total plus a design margin, typically 10-15%.
Inputs explained
- Filter loss(in wc)
- Enter the filter loss in in wc.
- Coil loss(in wc)
- Enter the coil loss in in wc.
- Duct friction loss(in wc)
- Enter the duct friction loss in in wc.
- Fittings loss(in wc)
- Enter the fittings loss in in wc.
- Other accessories loss(in wc)
- Enter the other accessories loss in in wc.
Worked example
Using the values the calculator loads with:
Inputs
- Filter loss0.4 in wc
- Coil loss0.3 in wc
- Duct friction loss0.5 in wc
- Fittings loss0.25 in wc
- Other accessories loss0.15 in wc
Results
- Total system static pressure1.6 in wc
- Select fan at (+15% margin)1.84 in wc
- Largest contributorduct
Frequently asked questions
Should I include filter loss at 'dirty' or 'clean' condition?
Design at a mid-to-dirty loading so the fan still delivers enough airflow as the filter loads up.
What if I'm missing a component?
Add its individual pressure drop from a duct pressure drop or fitting calculator and include it in the total.
What do I need to enter into the Fan System Pressure Loss Calculator?
Just 5 values: filter loss, coil loss, duct friction loss, fittings loss, other accessories loss. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Fan System Pressure Loss Calculator work out the answer?
Total fan system pressure loss is the sum of the pressure drops across every filter, coil, duct run, fitting and accessory in the airstream. It applies the formula SP_total = sum of all component pressure drops and shows the working so you can check each step by hand.
Is the Fan System Pressure Loss Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.