The heat load calculator uses a Manual-J style approximation: room volume, climate factors, insulation and sun exposure, plus internal loads from occupants and windows. The result is intended for quick field reference before running a full ACCA Manual J calculation.

Duct sizing uses the Darcy-Weisbach friction equation with a fully turbulent flow friction factor, and displays circular equivalent sizes per ASHRAE tables for round and rectangular ductwork.

Static pressure adds duct length, fittings, and component losses, then compares the total external static pressure against the fan rating at the required airflow.

The PT chart uses common saturation pressure/temperature data for R-410A, R-32, R-134a, and other refrigerants to convert gauge pressure to saturated temperature.

VRF pipe sizes are based on manufacturer-agnostic universal references for liquid and gas lines, with checks for maximum height and equivalent length limits.

Radiator output is corrected using EN 442 based on the actual mean water-to-room temperature difference, not the nominal 50 °C ΔT.

The AI tool organizes symptoms and field readings into a structured troubleshooting flow, with repair recommendations and high-risk warnings. It does not replace a certified technician's judgment.