Tools

Verify refrigerant charge from your gauge and probe readings: target vs. actual, add / recover, with the saturation math shown. Includes PT charts.

Round, rectangular and flex duct sizing by equal friction: CFM to diameter, velocity checks, and a friction-rate helper.

Solve the missing variable in the sensible heat equation Q = 1.08 × CFM × ΔT, with total and latent modes.

Evaporator temperature split vs. target from return conditions, a fast airflow-vs-charge diagnostic.

Airflow from tonnage at 350–450 CFM/ton, tuned to your climate.

Wet-bulb, dew point, humidity ratio, grains, enthalpy and density from dry-bulb plus one more property.

Total external static pressure and friction rate from component losses or measured readings.

Whole-house block heating and cooling load by ZIP: tonnage range and BTU with an oversizing check. A planning estimate, not an ACCA Manual J.

Full NEC chain: ampacity, ambient and conductor derating, terminations, small-conductor caps, voltage drop, breaker and EGC. Every step cited.

Can your panel take an EV charger? Both NEC 220.87 and 220.83 methods with a fits / load-management verdict.

Residential natural gas and propane sizing by the longest-length method: trunk and branches, with a tankless retrofit mode.

Total drainage fixture units and size branches, stacks and the building drain by slope (IPC 2021).

Water supply fixture units to peak GPM (Hunter's curve) and pipe diameter by velocity, per material.

AISC shape weight, dimensions and section properties with a scaled cross-section drawing.

Match a measured beam to AISC shapes (1873–2016) by weighted distance, for renovation and reuse research.

Rise, run and stringer layout with IRC PASS/FAIL checks, framing-square settings and a printable cut sheet.

Convert between Celsius, Fahrenheit, and Kelvin instantly, with formulas and reference points.