Regional standards, code-required load calculations and tighter homes still have not stopped gross oversizing. Why four…

Nobody plugs a new television straight into the wall socket. The protection routinely left off high-efficiency…

Whole-house dehumidifiers are not sized by square footage. The Manual J block load procedure most technicians…

How the total leakage duct test is run, which towns enforce it, and the permit costs…

NFRC labels carry the u-value and SHGC your load calculation depends on. Guessing them swings the…

The five biggest updates in the Manual S rewrite, and how far the 1995 edition had…

Break-even COP math from ACCA Manual H for deciding when a dual-fuel application actually saves the…

Which external static pressure to design a duct system around, and why designing at the PSC…

‘I have designed with these temperatures for decades’ does not satisfy an inspector. Where the correct…

Where returns belong for heating-only, cooling-only, and combination systems, and why application drives the decision.