Full catalog
Every HVAC calculator, organized.
Free tools across six categories. Each calculator is built against published code or engineering standards and reviewed by a named licensed technician. How the math gets verified.
System sizing
Get the right tonnage. Stop oversizing.
- BTU sizing calculator
- AC tonnage calculator
- Heat pump sizing
- and more
Cost & ROI
Real numbers, real bills, real payback.
- HVAC replacement cost
- Heat pump vs gas furnace
- SEER2 savings calculator
- and more
Efficiency
Decode the ratings that actually matter.
- SEER to SEER2 converter
- HSPF to HSPF2 converter
- EER vs SEER calculator
- and more
Ductwork & airflow
Free duct math that used to cost $400.
- Duct sizing (Manual D)
- Static pressure calculator
- CFM calculator
- and more
Refrigerant
R-410A, R-32, R-454B. All the math.
- Refrigerant charge calculator
- Superheat calculator
- Subcooling calculator
- and more
Pro tools
For technicians and serious DIYers.
- Wire size calculator
- Breaker size calculator
- Capacitor sizing
- and more