About
Built to answer one question, correctly.
WhatSize Appliance exists to answer the question that millions of homeowners ask every year: "What size [appliance] do I need?"
Standards-based
Every recommendation comes from public AHAM, DOE, ACCA, and NEMA publications — not vibes.
Transparent math
Click "How we calculated this" on any result to see the formula, step by step.
Always free
No paywalls, no signups. We earn a small Amazon commission when you buy through our links.
Our approach
Every calculator is built on publicly available standards:
- AHAM — Association of Home Appliance Manufacturers. Dehumidifier (DH-1-2019) and air purifier (CADR) standards.
- DOE — U.S. Department of Energy. Appliance energy and capacity standards (10 CFR 430).
- ACCA Manual J — Residential HVAC load calculation methodology.
- NEMA — National Electrical Manufacturers Association. Generator sizing.
Why we recommend products
WhatSize Appliance participates in the Amazon Associates program. When you buy a product through our links, we earn a small commission — at no extra cost to you. This is how we keep the calculators free.
Our product recommendations are based on customer reviews, expert testing data, feature comparisons, and value. We never recommend a product solely because of a higher commission rate.
Editorial standards
Every guide is reviewed for calculation accuracy before publication. Standards are re-checked quarterly. Sources are listed at the bottom of every page.
Founded by Yann Buf, HVAC tech and home-systems nerd. Reach out at hello@whatsizeappliance.com.