How we choose products

1. Start from the official spec sheet

We collect each product's specifications from the maker's own product page, manual, datasheet or support pages: sounds and volume range, battery life, filter type and CADR, room size, published noise levels, tank size and runtime, and which sensors a monitor uses. If a number can't be confirmed from the maker, a rating body or a government source, it stays out. Every guide ends with a list of the official sources behind it.

2. Check it against independent ratings

• Air purifiers: we look up each model's CADR in AHAM's Verifide directory and compare room sizes on AHAM's basis: room size in square feet equals the smoke CADR times 1.55, which works out to 4.8 air changes an hour. If a maker isn't in the directory, we say so and label its figure as the maker's own.
• ENERGY STAR: for air cleaners and dehumidifiers, we check ENERGY STAR's certified product list rather than the box.
• CARB: every portable air cleaner sold in California must be certified by the California Air Resources Board, and CARB's list shows whether it is a mechanical (filter-only) or electronic unit. We never recommend ozone generators.
• Dehumidifiers: we use pints-per-day ratings from the Department of Energy's current test procedure, in force since June 2019, and say when an older rating is being quoted.
• CO2 monitors: we distinguish true NDIR CO2 sensors from "eCO2" figures estimated from other sensors.

3. Name the traps

• Room sizes stretched by assuming fewer air changes an hour.
• "HEPA-type" filter labels, and filter names in general: the CADR is what tells you how much filtered air reaches the room.
• Decibel figures published without the distance or setting they were taken at.
• Old and new dehumidifier pint ratings, which aren't comparable.
• "CO2" readings that are estimates.
• Subscriptions behind features, and "phone-free" clocks that need an app and Wi-Fi to set up.

4. Match it to real rooms and routines

A sound machine that suits a nursery can be the wrong pick for a light sleeper in a city apartment. We match products to room size, light sleepers, side sleepers, shared bedrooms and travel. For nurseries we repeat the maker's own placement and volume guidance and nothing more.

5. Weigh value and upkeep

We favor products with clear documentation, available replacement filters, wicks and parts, published replacement intervals and a solid warranty, and we note patterns that owners widely report. We never show prices: the current price is always on the retailer's page.

6. Check every claim twice

Each factual claim in a guide is logged with the official page it comes from and the line that supports it, then checked a second time, independently, against the same sources. Where the two checks disagree, we go back to the official page and settle it there. Anything we can't confirm is cut.

7. Keep it current

A guide's "Updated" date changes only when its content changes. We re-check certifications, availability and subscription terms regularly, and replace discontinued models.

What we never claim

• Nothing on thisHUSH is medical advice, and we don't cover medical devices.
• We don't claim health or sleep outcomes. We describe what a product does (the sound it plays, the air it moves, what its sensor reads), not what it does for your body.
• We have not lab-tested the products we cover, and spec-sheet research is never presented as our own test results. If we ever add our own measurements, each one will say how it was taken, and this page will change first.