Free HVAC Tools

Free HVAC Tools

Thirteen free calculators, charts and reference tables for HVAC work. Pick one below. Each has its own page, and none needs an account or an install.

Refrigerant

Refrigerant PT ChartSaturated pressure against temperature for eight refrigerants, with bubble and dew values for the blends. Refrigerant Cylinder ColorsThe gray and yellow recovery cylinder, the red band on flammable refrigerants, and why the label decides.

Electrical

Wire and Breaker SizingMinimum circuit ampacity, maximum breaker (MOCP) and copper wire gauge from the compressor RLA and other loads. Capacitor Sizing TableThe typical dual run capacitor value in MFD for 1.5 to 5 ton units, as a fallback when the nameplate is unreadable. Ohms Law CalculatorTables that work every pairing of volts, amps, ohms and watts.

Airflow

Duct Velocity and CFMCFM from a rectangular duct's size and air velocity, worked for common sizes at 500 to 900 FPM. Fan Affinity LawsWhat a change in fan speed does to airflow, pressure and power.

Belts & Filters

Belt Cross-ReferenceType a V-belt size to see its width, its length and its equivalent belt. V-Belt Profile ChartThe top width and thickness of each V-belt section, and how a length code such as B50 reads. Filter SizesNominal versus actual measurements for common 1 inch and 2 inch HVAC filters.

Compliance

EPA Leak Rate CalculatorThe annualized leak rate against the 10%, 20% and 30% thresholds and the 15 lb gate.

Reference

HVAC Unit ConversionsTons to BTU/hr, inches of water column to pascals, airflow per ton, and SEER versus SEER2. Indoor Humidity GuideThe target range for indoor relative humidity and where comfort usually sits inside it.

Most of these charts, tables and calculators are also in Quick Reference in the free Equipment Tracker app, on your phone, so they work with no signal.