How SHGC and window orientation affect cooling loads. Worked example with ASHRAE orientation factors, overhang credit, and equipment impact.
Whole house ventilation ERV/HRV sizing: ASHRAE 62.2 formula, climate-driven ERV vs HRV selection, and effective vs nominal CFM at the unit.
Free HVAC load calculation software for contractors compared: ACCA-approved options, the free-tier traps, and the gap from free to Wrightsoft.
Manual J vs rule of thumb HVAC sizing: accuracy, time cost, permit acceptance, and the quantifiable costs of oversized systems. Comparison with worked numbers.
How to read a psychrometric chart for HVAC design. Step-by-step guide to the seven air properties, three real conditioning processes with worked numbers, and practical coil selection using SHR and apparatus dew point.
How to calculate air changes per hour for HVAC ventilation design. Covers the ACH formula, ASHRAE 62.1 and 62.2 requirements, occupancy-based vs. volume-based methods, and a worked office ventilation example.
How many BTU do you need to heat a room? The answer depends on six factors the square footage shortcut ignores. Decision guide for HVAC contractors with real numbers and sizing tables.
Complete worked example of a room-by-room heat loss calculation for residential HVAC sizing. Real numbers, every formula step, and common errors that inflate your load.
Learn how to perform a Manual J load calculation for residential HVAC projects. Step-by-step process with common mistakes, ACCA sizing limits, and real-world input tips for contractors.