HVAC Calculators 20
Electrical Calculators 26
About These Calculators
All calculations follow published engineering standards: ASHRAE 90.1, 62.1, and Handbook of Fundamentals for HVAC; NEC 2023 (NFPA 70) for US electrical; IEC 60364 for international electrical. Results are for preliminary engineering use — verify with full Manual J, Manual D, or detailed load analysis before equipment selection. See our Methodology page for formula references.