Works with no signal
Every calculation runs on your device from the values you enter. Nothing is uploaded, and once the app is set up it works on the job site even with no signal at all.
HVAC commissioning calculations for the real world.
Twenty-two commissioning calculators for iOS: electrical, airflow, duct, thermal, water, and psychrometric.
Coming to the App StoreStart a free trial today!
Why it exists
Built for work
Sixty-point number fields and buttons, with high-contrast results. Designed for real work, not desk work.
Metric and Imperial
Switch unit systems at any time from Settings. Calculations run in SI internally and convert only for display, so switching never changes an answer.
Built around the calculations you actually repeat
Electrical
Fan Power
Enter volume flow, total static pressure rise, and fan and motor efficiencies. You get shaft power and motor input power together, so you can size the motor and sanity-check the nameplate in one pass.
Electrical
Cable Sizing
Works from the IEC 60364 method B2 ampacity tables, then applies the PVC temperature derating factors from Table B.52.14 and a grouping factor. It returns a standard mm² size rather than a raw number, so the answer is one you can order.
Airflow
Airflow Balance
Enter measured supply, return, and exhaust flows and it reports the imbalance directly, along with the outdoor-air fraction the balance implies. Built for the moment on site when the numbers do not add up and you need to know by how much.
Duct
Friction Loss
Uses the ASHRAE/SMACNA friction correlation for galvanised steel rather than a lookup chart, so the answer is continuous across diameters. Elbows at 90° and 45° are added as equivalent lengths, giving a total pressure drop for the run instead of just a rate per metre.
Water
Pipe Flow
Computes the Reynolds number, selects the correct friction-factor regime, and returns velocity alongside pressure drop per metre. Laminar flow uses Hagen-Poiseuille and turbulent flow uses Swamee-Jain, so the result stays honest across the full range rather than assuming turbulence everywhere.
Psychrometric
Cooling Coil
Derives humidity ratio and enthalpy at both entering and leaving conditions, then splits the duty into sensible and latent components. It is the app’s most involved calculation, and it replaces a psychrometric chart and a straight edge on site.
All 22 calculators
Once the app is unlocked, every calculator works offline, in metric or imperial, and any result can be saved to a project.
Electrical
- Fan PowerFan shaft power and motor input power from airflow, static pressure rise, and efficiencies.
- Specific Fan PowerMotor input power per unit of airflow — the W/(m³/s) figure used to benchmark system efficiency.
- AmperageSingle- and three-phase current from active power, voltage, and power factor.
- Power (V & I)Active and apparent power from voltage and current, plus IEC voltage drop in volts and percent.
- Cable SizingIEC 60364 conductor sizing from design current, with ambient-temperature and grouping derating applied.
Airflow
- Duct Velocity & VolumeFlow rate from velocity, or velocity from flow rate, for round or rectangular duct.
- Airflow BalanceSystem imbalance across supply, return, and exhaust, with the resulting outdoor-air fraction.
- Air ChangeAir changes per hour from room volume and flow rate, or the flow needed to hit a target ACH.
Duct
- Duct SizingRequired round duct diameter for a target velocity, plus ASHRAE equivalent diameter for rectangular duct.
- Friction LossASHRAE friction rate for galvanised duct, velocity pressure, and total drop including elbow equivalent lengths.
Thermal
- Sensible HeatSensible load from airflow and dry-bulb temperature difference, in BTU/hr or kW.
- Latent HeatLatent load from airflow and humidity-ratio change, in BTU/hr or kW.
- Mixed Air TemperatureMixed-air temperature from the outdoor-air fraction and the outdoor and return air temperatures.
- Coefficient of PerformanceCOP from thermal capacity and electrical input, with the equivalent EER.
Water
- Pipe FlowVelocity, Reynolds number, and Darcy-Weisbach pressure drop for a given flow, bore, and pipe roughness.
- Valve FlowKv or Cv from flow and differential pressure, or solve back for flow or pressure drop from a known coefficient.
- Flushing / DosingSystem volume from pipe runs, flush duration for a chosen number of system volumes, and inhibitor dose.
Psychrometric
- State ConditionsFull moist-air state from dry-bulb plus RH or wet-bulb: humidity ratio, dew point, and enthalpy, corrected for altitude.
- Air MixingMass-weighted mix of two airstreams, returning the mixed dry-bulb temperature and humidity ratio.
- Point to PointTotal, sensible, and latent load between two air states, signed for heating or cooling, with the moisture rate.
- HumidificationWater mass flow needed to bring an airstream from its inlet condition up to a target indoor relative humidity.
- Cooling CoilCoil duty split into sensible, latent, and total from entering and leaving conditions and airflow.
Save results to a project
Give a job a name and save any calculation to it, inputs and results together, so a figure you produced on Tuesday still makes sense on Friday. Projects are stored on the device.
Nothing is uploaded and there is no account to create. Delete the app and the data goes with it.
No accounts. No analytics. No tracking.
The app collects nothing about you, requests no iOS permissions, and never uploads your calculations or projects. There are no third-party SDKs, no advertising, and no crash reporting. In-app purchases are handled entirely by Apple, so no payment details ever reach the developer.