Air purifiers and humidifiers are designed to improve your indoor air quality. Running these devices can boost your home’s freshness and comfort levels, especially when operated in tandem. But as with most appliances, they do have the potential to develop odors.
Have you noticed your humidifier smells musty? Wondering, “Why does my air purifier smell?” Here’s a brief guide to odors that are normal versus those that need your attention.
Why Can Humidifiers Develop Odors?
Off-Gassing
You’ve probably noticed a “new product smell” upon opening any device, and humidifiers are no exception. Luckily, this is simply a result of off-gassing, the temporary release of odors that may have gotten trapped during production and packaging. If you’re sensitive to smells, air the device out for several days before use.
Minerals & Dissolved Materials
If you ever find yourself asking, “Why does my humidifier smell like urine,” don’t panic. While the odor is off-putting, it’s likely from a harmless source: your water. Over time, if minerals from tap water build up in the device’s tank, they may settle and produce the unappealing scent. While you could use distilled water to avoid the issue altogether, Canopy devices are unique in that they work fine with tap water as long as the filter is replaced regularly1.
Mildew
Mold and mildew are hard scents to describe, but they’re immediately recognizable if you’ve smelled them before. This damp, earthy smell coming from a humidifier usually indicates mold growth.
Mold and mildew can be particularly irritating for people with allergies or respiratory issues, so be sure to clean your device regularly2.
Expired or Overused Filter
Yeast, sometimes described as a “wet dog smell,” occurs when bacteria accumulate. If your filter is full of trapped bacteria because it hasn’t been changed on time, you may notice this unpleasant scent coming from your humidifier 2.
Why Can Air Purifiers Develop Odors?
Off-Gassing
Like new humidifiers, air purifiers may have a noticeable plastic smell upon their first use. As with most devices, the initial odor will dissipate over time. Simply place your air purifier in a separate space for a day or so if the scent is bothersome.
Ozone or Ionization
Certain air purifiers use ionization to charge airborne particles, resulting in a subtle scent of ozone (sometimes described as a “sharp” smell) near the device. For the greatest odor elimination, look for an air purifier with an activated carbon filter, which traps scents.
Filter Materials
As the HEPA or activated carbon filter in your unit collects airborne particles, it may develop a noticeable smell. This should only occur if the filter becomes saturated, at which point a replacement is needed.
Expired or Overused Filter
If your air purifier smells bad after a while, it could simply be time to replace the filter. With impurities like pet dander, dust, and kitchen odors trapped in one place, it’s only natural that the filter will begin to produce a sour smell as it fills up. Fortunately, swapping it out at the recommended intervals resolves the issue3.
What to Do If Your Canopy Device Has an Odor
Canopy devices are built for home comfort and convenience, so both our air purifiers and humidifiers are equipped with features that help prevent odors. For one, Canopy humidifiers have mold-resistant Smart Persistent Airflow™ (SPA) technology, which keeps the device’s fan running when water is present in the tray to reduce the risk of mold. And since every component that touches water in our Bedside, Nursery, and Large Room humidifiers can be cleaned in the dishwasher, routine maintenance is hassle-free and will go a long way in preventing unwanted scents.
Cleaning your air purifier is also important for smooth, odor-free operation. The device’s faceplate and aroma diffuser are safe to wash in the top rack of your dishwasher, while other components can be wiped down with a cloth as needed.
Regular filter replacements for Canopy air purifiers and humidifiers are also effective ways to keep your devices running well and blocking out odors. Our Bedside, Nursery, and Large Room humidifiers have filters that should be replaced every 5 to 7 weeks, which is made even simpler with our filter subscriptions or bundles, so you always have a replacement on hand.
Keep in mind that water quality plays a role in replacement frequency; water that’s richer in minerals may saturate filters sooner, resulting in the telltale urine smell discussed above. In between replacements, allow your filter to dry out fully once a week to maintain freshness.
Canopy Air Purifiers come equipped with preinstalled Protect Plus filters, which have activated carbon, making it an air purifier/odor eliminator all in one. In most cases, the filter will need to be replaced every six months or 720 hours of use. Don’t worry if you forgot to keep track; the device’s filter indicator illuminates when it’s time for a replacement.
For streamlined swaps, explore our bundle and subscription options for humidifier filters and air purifier filters so a fresh one is always available.
FAQ
Is it normal for a new humidifier or air purifier to smell?
It’s normal for either device to produce a faint chemical or plastic smell initially. This odor will fade with use.
Why does my humidifier smell after sitting unused?
This may indicate the presence of mold or bacterial growth, which can come from stagnant water. Address the odor by cleaning the device’s tank and other components that come into contact with water and replacing the filter.
Why does my air purifier smell after changing the filter?
You may be noticing a faint smell from off-gassing, which occurs when new products are first opened and used. The scent should dissipate shortly after use.
How can I keep my humidifier and air purifier from smelling?
Prevent odors from developing in your humidifier by cleaning its components regularly, replacing the filter at recommended intervals, and allowing the filter to dry out completely once each week. Avoid odors from your air purifier by cleaning it as needed and swapping out the filter when the indicator light illuminates.
Sources:
- Yang, L. (12 April 2024). Why Does Your Humidifier Smell Bad and How to Fix It? Air Smartly. Retrieved July 29, 2026, from https://airsmartly.com/humidifier-smell-bad/
- Why Does My Humidifier Smell: A Simple Guide. Southwest Heating & Cooling. Retrieved July 29, 2026, from https://southwestheating.com/why-does-my-humidifier-smell/
- (10 April 2023). Why Does Your Air Purifier Smell Sour? BelAire. Retrieved July 29, 2026, from https://belaire.com/why-does-your-air-purifier-smell-sour/
