Air Purifier Noise Simulator | indoorair.guide

Hear and compare common decibel levels to understand what an air purifier or appliance will sound like in your room. The Noise Simulator uses the Web Audio API to generate calibrated reference tones on a logarithmic scale and supports side-by-side A/B comparison between any two levels.

• Reference levels from 20 dB (rustling leaves) through 70 dB (vacuum)
• A/B compare mode for two levels side by side
• Logarithmic perceived-loudness scaling — each +10 dB sounds roughly twice as loud
• Helpful when choosing a bedroom-safe purifier, AC, or air-cleaning device
• Pure browser audio — nothing recorded, uploaded, or stored

Why decibel numbers are misleading on their own

Decibels (dB) are logarithmic, not linear. A purifier rated 50 dB is not "25% louder" than one rated 40 dB — it is perceived as roughly twice as loud. This is why a 5 dB difference on a spec sheet matters far more in a bedroom than the number suggests, and why marketing claims of "whisper-quiet 40 dB" can still be intrusive at night.

The Noise Simulator lets you hear the difference before you buy. Pick the rated noise level on the highest fan speed and on the lowest fan speed of a purifier you are considering, and listen to both at your usual playback volume. If the high-speed tone is uncomfortable, you will not run the purifier on that setting at night — and the manufacturer’s CADR rating, which is measured on max, will not be the CADR you actually get.

Reference points

Common indoor reference levels: 20 dB is a quiet bedroom at night; 30 dB is a whisper at 1 m; 40 dB is a refrigerator hum; 50 dB is a quiet office; 60 dB is normal conversation; 70 dB is a vacuum cleaner. For sleep, anything above 35 dB is consistently disruptive in published sleep studies, and WHO Night Noise Guidelines recommend bedroom levels below 30 dB.

For an air purifier in a bedroom, the spec to look at is the manufacturer-published noise on the lowest fan speed. Target ≤30 dB if it will run all night. For a living-room or office purifier, a 35–45 dB medium speed is acceptable for most people.

Compare mode

Compare mode plays two reference tones in alternation so you can hear the difference directly rather than from memory. Use it to compare two purifier models, the highest and lowest fan speeds of a single model, or a purifier against the ambient noise of your room (traffic, ceiling fan, AC).