HVAC Logic

What it does

HVACLogic is an open-access, deterministic engineering calculation suite executing 100% client-side with full offline PWA support. It delivers 21 engineering tools for air duct sizing (Colebrook-White), Manual J heating/cooling loads, SEER2 AC tonnage, and A2L refrigerant diagnostics. Built with zero tracking cookies, transparent physics equations, and 1-click printable PDF job submittals.

Transparent, peer-reviewed engineering calculators for HVAC airflow, duct sizing, cooling loads, heat pumps & field diagnostics. 100% free & client-side.

Transparent thermodynamic and fluid mechanics formulas built on ASHRAE, ACCA, EPA, and IECC standards. 100% client-side precision. Equal friction sizing for round, rectangular & oval ductwork per ASHRAE & SMACNA. Pressure-temperature curves for low-GWP A2L (R-454B, R-32) & legacy refrigerants. 4" to 20" flexible duct CFM airflow capacities with 0% to 30% sag & compression derates. Confined space indoor and outdoor combustion air sizing per NFPA 54 & IFGC Sec. 304. Instant nominal tonnage, SEER2 rating, and CFM lookup for Carrier, Trane, Lennox & Daikin. Thermal balance point, supplemental heat staging, and COP derating across sub-zero temps. Calculate sensible heat gains, solar…from hvaclogic.org

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