Calculators
6
For every major appliance category
Sizing guides
60
By room, by size, by scenario
Updated
June 2026
Refreshed against the latest AHAM, DOE & ACCA publications
By the numbers
Industry standards cited
7
AHAM, DOE, ACCA, NEC, ASPE, EPA, ENERGY STAR — each linked to the source publication on every result.
Quick reference charts
6
One per category. Look up the number in 30 seconds.
Head-to-head comparisons
6
50 vs 70 pt, 9k vs 12k BTU, tank vs tankless, …
US-only
100%
Standards, climate zones, codes, and prices are US-specific.
Cited standard editions
AHAM DH-1-2022 · DOE 10 CFR 430 · ACCA Manual J 8th · NEC 702
Every result links to the specific edition. We don't cite "AHAM" generically — we cite the year and section.
What are you sizing?
Pick a category — most calculators take 30 seconds.
Popular sizing guides
The most-searched scenario in each category.
Quick reference charts
Look up the exact number in seconds — no calculator needed.
Air purifier sizes chart
CADR by room size & concern (AHAM AC-1)
Ceiling fan size chart
Blade span by room area & ceiling height (ENERGY STAR)
Dehumidifier sizes chart
Pint capacity by sq ft & dampness (AHAM DH-1-2022)
Generator wattage chart
Running + starting watts for 50+ appliances (NEC 702)
Mini split sizes chart
BTU by sq ft & climate zone (ACCA Manual J)
Sump pump sizes chart
GPH by HP & lift height (Zoeller / Wayne curves)
Water heater sizes chart
Tank gallons & tankless GPM by household (DOE 10 CFR 430)
Tankless water heater size chart
GPM by household & climate (ENERGY STAR + AHRI)
How it works
Three steps to the right size
1
Pick a calculator
Choose the appliance you're sizing from our category list.
2
Enter your details
Room size, household, climate — a few quick inputs.
3
Get the right size
Exact capacity + top models matched to your inputs.