W WhatSize
Reviewed by Alex Chen & Morgan Webb Updated June 30, 2026
Alex Chen

HVAC, thermal & air-quality research lead

Alex Chen

Research lead for HVAC, thermal, and indoor-air-quality sizing. Focus areas are ACCA Manual J load calculation, heat-pump performance curves, AHAM DH-1 dehumidifier capacity, and AHAM AC-1 CADR / air-changes-per-hour methodology for air purifiers.

On the team since 2022 184 citations on the site

What Alex reviews

Domain: Air Purifier, Dehumidifier, Mini Split

Methodology

Every result is checked against the cited standard's exact section, not just its name. When a calculator gives an answer that differs from a 'rule of thumb' on a forum post, the calculator is right until proven otherwise.

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