Fan and blower efficiency from airflow, pressure and motor power: density correction, fan laws, motor loading, and the yearly energy and cost of damper, inlet vane and variable speed control.
USD 39 one-time purchase
Download the sample report (PDF)
Need it once? Use it online: check your data free, unlock results from USD 9 for 3 runs.
What it does
Total and static efficiency
From fan pressure, airflow and shaft power, with the compressibility coefficient, in the style of AMCA 210 and ISO 5801 definitions.
Motor loading
Motor loss model with load, efficiency at that load, overall efficiency and specific fan power.
Air density
From temperature, humidity and barometric pressure or altitude, as moist air, or enter your own.
Fan laws
New flow, pressure, power, motor load and tip speed for a new speed, impeller diameter or air condition.
Flow control comparison
Outlet damper, inlet vanes and variable speed over up to four flows with hours per year, energy and cost saved.
Selectors
Efficiency basis, pressure and power measured, density source and control method; rows you do not need disappear.
Built for engineers
- Visible formulas — nothing hidden, so you can check every step.
- Fully referenced — methods from the standard references, checked against their published worked examples.
- Safe to share — sheets are protected against accidental edits, with an open password so you can still customise.
- Built-in input checks — clear warnings for impossible inputs and values outside typical ranges.
For engineering estimates; verify against site data. Code-based methods are aligned with the publicly documented procedure; they are not a licensed reproduction or a certification.
Preview the workbook
Real pages from the workbook with its built-in example loaded (example data, not a measured plant). Choose a page below, or select the large image to enlarge it.
Specification and checks
| Format | Excel workbook (.xlsx), no macros |
| Version | v1.0 |
| Works in | Excel 2010 or later, Windows and Mac |
| Units | SI, US and British, mixed freely |
| Includes | Guide tab with method and references, calculator, print-ready report |
| Checked against | About 195 recalculated runs against an independent Python model (moist-air density by mole-fraction mixing, numerical root finds): all 48 selector combinations, SI, US, British and industry units and 135 edge cases; largest deviation 0.00004 %. |
| Free version | Try the free pump affinity laws calculator |
Online tool or Excel workbook?
| Online tool | Excel workbook (this page) | |
|---|---|---|
| What it does | The same sheet as the Excel workbook, run in your browser | Fan and blower efficiency from airflow, pressure and motor power: density correction, fan laws, motor loading, and the yearly energy and cost of damper, inlet vane and variable speed control. |
| Cost | Check your inputs free. Results: 3 runs for USD 9, or every online tool for USD 15 a month (USD 99 a year) | USD 39 once, yours to keep |
| Input checks and findings | Every input checked; findings with the unlocked results | Every input checked, with findings and recommendations |
| Report for your calculation file | Printable results sheet | Print-ready report with your plant, tag, document number, revision and sign-off |
| Formulas | Method described in the guide | Every formula visible in its cell |
| Save, edit and rerun your cases | Each run separately | Yes: keep and edit your own file |
| Works offline, on a plant PC | No, needs the internet | Yes: Excel 2010 or later, Windows and Mac |
Online access and the Excel workbook are separate licences: one does not include the other.
Compatibility, licence and support
| File | Excel workbook (.xlsx), no macros, version v1.0; works in Excel 2010 or later on Windows and Mac. Sheets are protected against accidental edits, with an open password so you can customise. |
| Licence | Single user. A team licence (up to 5 named users) is 3 × the shop price; site licences on request — licence terms. |
| Updates | Updates to this major version are included; download them again from the link in your receipt. |
| Support | Email [email protected] with your order number — questions on the method, your inputs or your results are welcome. |
| Refunds | If the tool does not work as described, or has an error we cannot fix, email [email protected] with your order number within 14 days of purchase and we will refund you in full. Refunds are not offered for a change of mind once a file has been downloaded. Read the full refund policy. |