Recessed Lighting Layout Guide 2026: Spacing, Lumens & Can Lights
Plan a recessed lighting layout in 2026 using room dimensions, maximum spacing, lumen targets, ceiling height, beam angle and wall-wash geometry.
Building Trades guides
HVAC airflow and duct-sizing tools for building-system planning. These guides explain the assumptions, choices, and real-world factors behind the numbers.
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4 articlesHow to Calculate Duct Area in 2026: Round and Rectangular
Calculate HVAC duct cross-sectional area, airflow area and sheet-metal surface area for round, rectangular and transition sections with worked examples.
HVAC Trunk, Plenum and Return Duct Sizing: 2026 Guide
Plan HVAC supply trunks, plenums and return ducts using room airflow, downstream CFM, available static pressure, effective length and verification.
How to Size HVAC Ducts: CFM, Velocity, and Friction Rate
Size HVAC ducts using room airflow, air velocity, available static pressure, total effective length, and a proper friction-rate calculation.