Free HVAC Field Calculators
The math you actually do on a service call — refrigerant pressures, duct sizing, static pressure, balance points, and electrical. Open it on the truck, use it, close it.
Refrigerant PT Chart
Saturation pressure and temperature, both directions, for R-410A, R-32, R-454B, R-22, R-134a and more.
Open toolDuct Sizing Calculator
Size round or rectangular duct from airflow and friction rate, with a velocity check built in.
Open toolStatic Pressure Calculator
Add supply and return static readings to see total external static pressure against the nameplate.
Open toolHeat Pump Balance Point
Find the outdoor temperature where heat pump capacity meets the home's heat loss, and the aux heat gap.
Open toolElectrical Calculators
Ohm's law, single- and three-phase power, voltage drop, wire sizing, and NEMA voltage unbalance.
Open toolWhy these are free
Because a calculator shouldn't be behind a paywall when you're standing in a mechanical room. These tools stay free and open to anyone. The paid app is for the harder part — diagnosing a system you've never seen before.
- AI troubleshooting that works through symptoms step by step
- Manufacturer error-code decoding, including brand-specific codes
- Manuals, wiring diagrams, and a searchable resource library
- A repair forum with other working techs