The numbers you need on the roof.
Free HVAC calculators and field reference for techs. Fast on your phone, no login, no app to download.
Calculators
Superheat & Subcooling Calculator
Enter your line temps and saturation temps; get superheat and subcooling instantly.
TSHTarget Superheat Calculator
Target superheat for piston and cap-tube systems from indoor wet bulb and outdoor dry bulb.
DUCTDuct Size Calculator
CFM and friction rate in; round and rectangular duct size, velocity and friction out.
CFMFurnace Airflow from Temperature Rise
Estimate furnace CFM from input BTU, efficiency and the supply/return temperature rise.
µFCapacitor Check Calculator
Measured amps and volts to microfarads, with a pass/fail against the rated value.
UNITSHVAC Unit Converter
Tons, BTU/h and kW; °F and °C; psi, kPa and in. w.c.; CFM and L/s; oz, lb and kg.
Knowledge base
Refrigerants & Charging
PT basics, superheat and subcooling, A2L refrigerants, recovery, leaks. Coming soon.
Troubleshooting by Symptom
No cooling, no heat, short cycling, frozen coils, noises, leaks. Coming soon.
Error & Fault Codes
By brand and equipment: furnaces, mini-splits, heat pumps. Coming soon.
Equipment by Brand
Model and serial formats, unit age, common failures. Coming soon.
Electrical & Controls
Capacitors, contactors, motors, thermostat wiring, boards. Coming soon.
Heating
Gas furnaces, combustion and CO, heat pumps and defrost, boilers. Coming soon.
Airflow & Ductwork
Static pressure, CFM, duct sizing, returns and filters. Coming soon.
Load & Sizing
Manual J and S basics, tonnage, rules of thumb vs. real calcs. Coming soon.
Mini-Splits & VRF
Installs, line sets, flaring, evacuation, commissioning. Coming soon.
Indoor Air Quality
Humidity, ventilation, filtration, UV. Coming soon.
Codes, Regs & Compliance
EPA 608, the AIM Act, A2L mitigation, permits, licensing. Coming soon.
Install Best Practices
Brazing with nitrogen, evacuation, startup checklists. Coming soon.
Tools & Gear
What to carry and what's worth the money. Coming soon.
Career & Certification
EPA 608 and NATE prep, licensing by state, pay. Coming soon.
Business of HVAC
Pricing, hiring and marketing for shop owners. Coming soon.