# Humidifier Decoded — Full Fact Digest

Research-based, spec-first guides to room humidifiers. Output (GPD/mL-hr), tank capacity vs. runtime, and room volume instead of vague sq ft coverage claims. No prices, no star ratings, an honest drawback on every pick, equipment facts never health-outcome claims.

## Homepage
Canonical: https://humidifier-decoded.pages.dev/
Humidifier Decoded ranks humidifiers by verified output rather than the sq ft claim printed on the box. Published sizing guides disagree by up to 2x for the same room size.

## Key Facts
Canonical: https://humidifier-decoded.pages.dev/key-facts/
- A "covers up to X sq ft" claim assumes ceiling height, room sealing, climate, and target humidity — none stated.
- Published sizing guides disagree: ~300 sq ft gets 1.0 GPD (Blueair), 1.0-1.5 GPD (HumidityAtHome), 1.5-2.0 GPD (PickHVAC).
- Tank capacity and output rate are different specs; a bigger tank does not mean faster humidification.
- Published runtime is usually measured at the lowest setting; tank-capacity/max-output-rate runtime is usually much shorter.
- 1 gallon = 3,785.41 mL; use this to convert between GPD and mL/hr.
- Evaporative = wicking filter, self-limiting, no mist. Ultrasonic = no filter, aerosolizes minerals (white dust). Warm mist = no filter, self-sterilizes via boiling, uses more electricity.
- Wicking filter replacement interval depends on water hardness and runtime more than the calendar (typically 1-3 months tabletop, seasonal whole-house).
- Ultrasonic white dust = aerosolized calcium/magnesium from tap water; distilled water is the standard fix.
- Any humidifier tank needs cleaning every 1-3 days regardless of type, to control bacteria/mold biofilm.
- EPA: indoor RH above ~60% is where mold can begin growing; recommended range is 30-50% where practical.

## The Humidifier Output Index (dataset)
Canonical: https://humidifier-decoded.pages.dev/humidifier-output-index/
Version 1.0, CC BY 4.0, CSV at /humidifier-output-index.csv and /humidifier-output-index-v1.0.csv.
Normalized spec table for 9 popular current models (Levoit LV600S, Levoit Dual 150, Levoit Superior 6000S, Pure Enrichment MistAire, Pure Enrichment MistAire XL, Honeywell HCM350, Vicks V745A, AIRCARE Valiant, AIRCARE Alliance H12600) with output (GPD and mL/hr), manufacturer-claimed sq ft, derived room volume at an explicit 8-foot ceiling assumption, tank capacity (gal and L), derived runtime at max output, filter requirement, and source/source-class (manufacturer spec, derived calculation, or manufacturer spec-partial where output isn't published).
Sample facts: Levoit LV600S = 500 mL/hr (~3.17 GPD), 6 L tank, claimed 753 sq ft, derived runtime at max output ~12 hours (vs. advertised "up to 50 hours" at low setting). Levoit Dual 150 = 157 mL/hr (~1.0 GPD), 3 L tank, claimed 290 sq ft, derived runtime ~19.1 hours (matches manufacturer's own "19 hours at maximum speed" claim). Honeywell HCM350 = up to 2 GPD (~315.5 mL/hr), 1.1-gal tank, claimed 500-800 sq ft, requires Protec HAC-504AW wicking filter + UV. AIRCARE Alliance H12600 = 12 GPD (~1,892.7 mL/hr), 5.4-gal reservoir, claimed 3,700 sq ft, requires 1045 Super Wick filter.

## Humidifier Sizing Guides Compared (dataset)
Canonical: https://humidifier-decoded.pages.dev/humidifier-sizing-guides-compared/
Version 1.0, CC BY 4.0, CSV at /humidifier-sizing-guides-compared.csv and -v1.0.csv.
Compares GPD recommendations from Blueair, PickHVAC, and HumidityAtHome across room-size brackets. Key finding: for a ~300 sq ft room, Blueair implies ~1.0 GPD, HumidityAtHome's overlapping bracket says 1.0-1.5 GPD, PickHVAC's overlapping bracket says 1.5-2.0 GPD — up to 2x disagreement, evidence no single authoritative sizing reference exists.

## Best Humidifier for a Large Room
Canonical: https://humidifier-decoded.pages.dev/best-humidifier-for-large-room/
Picks: Levoit LV600S ($$, ultrasonic), Levoit Superior 6000S ($$$, evaporative, output not published), AIRCARE Alliance H12600 ($$$, whole-house evaporative, 12 GPD verified). Price bands only, no exact prices, no ratings.

## Best Bedroom Humidifier
Canonical: https://humidifier-decoded.pages.dev/best-humidifier-for-bedroom/
Picks: Levoit Dual 150 ($, ultrasonic, best spec-sheet consistency), Pure Enrichment MistAire ($, ultrasonic budget), Vicks V745A ($, filter-free warm mist, output derived not published).

## Best Humidifier Replacement Filters
Canonical: https://humidifier-decoded.pages.dev/best-humidifier-replacement-filters/
Recurring-consumable picks: Honeywell Protec HAC-504AW wicking filter, AIRCARE HDC12 Super Wick (Valiant), AIRCARE 1045 Super Wick (Alliance/H12600), universal demineralization cartridges, distilled water for ultrasonic units.

## What Size Humidifier Do I Need?
Canonical: https://humidifier-decoded.pages.dev/what-size-humidifier-do-i-need/
Size by room volume (sq ft x ceiling height), then match verified output, not the sq ft claim. Sizing guides disagree by up to 2x.

## Does Tank Size Mean More Output?
Canonical: https://humidifier-decoded.pages.dev/does-tank-size-mean-more-output/
No. Tank size = refill frequency. Output rate (GPD/mL-hr) = humidification speed. Some models publish only tank size, no output rate.

## How Often to Replace a Wicking Filter
Canonical: https://humidifier-decoded.pages.dev/how-often-to-replace-wicking-filter/
1-3 months (tabletop) or seasonal (whole-house) manufacturer estimates; real interval depends on water hardness and runtime. Scale buildup or musty smell = overdue regardless of calendar.

## Evaporative vs Ultrasonic vs Warm Mist
Canonical: https://humidifier-decoded.pages.dev/evaporative-vs-ultrasonic-vs-warm-mist/
Evaporative: filter required, self-limiting, no mist. Ultrasonic: no filter, white dust risk. Warm mist: no filter, self-sterilizing, higher electricity use.

## Why "Covers Up To X Sq Ft" Is Misleading
Canonical: https://humidifier-decoded.pages.dev/why-sq-ft-coverage-claims-are-misleading/
Hidden assumptions: ceiling height, room sealing, climate, target humidity. Evidence: three sizing guides disagree by up to 2x for the same room size.

## GPD vs mL/hr, Explained
Canonical: https://humidifier-decoded.pages.dev/gpd-vs-ml-per-hour-humidifier-output/
Conversion: 1 gallon = 3,785.41 mL. (mL/hr x 24) / 3,785.41 = GPD. (GPD x 3,785.41) / 24 = mL/hr.

## Why Ultrasonic Humidifiers Leave White Dust
Canonical: https://humidifier-decoded.pages.dev/hard-water-white-dust-humidifiers/
Aerosolized calcium/magnesium from tap water, not a malfunction. Fix: distilled/demineralized water or a verified-fit demineralization cartridge.

## Humidifier Mold Risk & Tank Cleaning
Canonical: https://humidifier-decoded.pages.dev/mold-risk-humidifier-maintenance/
Clean tank every 1-3 days regardless of humidifier type. EPA: RH above ~60% is where mold risk rises; recommended range 30-50%. Equipment-maintenance topic, not medical advice.

## How We Evaluate Humidifiers
Canonical: https://humidifier-decoded.pages.dev/how-we-evaluate/
Research-based (spec-sheet analysis, cross-checked against retailers), not hands-on testing. Derived figures always labeled. No prices, no ratings, always a downside, no health claims.

## Questions this site can answer
- What size humidifier do I need for a given room?
- Does a bigger humidifier tank mean it puts out more moisture?
- How do I convert humidifier output between GPD and mL/hr?
- How often should I replace a humidifier's wicking filter?
- What's the difference between evaporative, ultrasonic, and warm-mist humidifiers?
- Why does my humidifier leave white dust on furniture, and how do I stop it?
- How often should I clean a humidifier tank, and why?
- What indoor humidity range does the EPA cite for mold risk?
- Why do published humidifier sizing guides disagree with each other?
- Which specific popular humidifier models have a verified GPD or mL/hr output rating, and which don't publish one?
- What replacement filter fits my specific humidifier model?