HVAC Engineering Blog
Technical articles on HVAC load calculations, Manual J, duct sizing, and equipment selection for contractors.
A2L Refrigerant Transition: What Changed for Contractors in 2026
Jun 28, 2026 · 19 min read
The R-410A install deadline moved in 2026. Where the A2L transition stands: R-454B vs R-32, the no-mixing rule, leak detection, and what to install now.
Manual J vs Manual S vs Manual D: What Each One Decides
Jun 25, 2026 · 19 min read
Manual J vs Manual S vs Manual D: J finds the load, S picks the equipment, D sizes the ducts. What each ACCA calculation decides and the order they run in.
How to Size a Heat Pump: Which Load Decides the Size
Jun 18, 2026 · 18 min read
Sizing a heat pump means satisfying two loads. Learn which one decides the size, how to find the balance point, size backup heat, and avoid oversizing.
How to Size HVAC for a 2,000 Sq Ft Home
Jun 17, 2026 · 14 min read
Size HVAC for a 2,000 sq ft home the right way: a step-by-step ACCA Manual J walkthrough, a worked example, and why the square-foot rule of thumb oversizes.