Static Pressure Calculator
Total external static pressure health check.
Enter your values
ⓘ Live results
Results
- Total external static
- 0.78 in w.c.
- Percent of blower rating
- 156%
- Dominant restriction
- supply side
- In pascals
- 194
- Verdict
- Over rating — airflow and capacity are suffering
Quick answer
Total external static pressure is the supply reading plus the absolute value of the return reading, and should stay at or under the blower's rating, usually 0.5 in w.c.
TESP = supply static + |return static|
How to use the Static Pressure Calculator
- 1Drill test ports upstream and downstream of the air handler.
- 2Record the supply and return readings with a manometer.
- 3Enter the blower's rated static from the data plate.
Worked example
Using the values the calculator loads with:
Inputs
- Supply static0.42 in w.c.
- Return static0.36 in w.c.
- Blower rated static0.5 in w.c.
Results
- Total external static0.78 in w.c.
- Percent of blower rating156%
- Dominant restrictionsupply side
- In pascals194
- VerdictOver rating — airflow and capacity are suffering
Frequently asked questions
What is a good static pressure?
0.5 in w.c. or less total on most residential equipment; many real systems measure 0.8 or worse.
What causes high static?
Undersized returns, dirty filters, crushed flex duct and restrictive coils are the usual culprits.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.