A portable or whole-home humidifier is a great way to maintain optimal indoor air quality during the dry winter months. But keeping it clean takes a little work. And if they’re not cleaned regularly, humidifiers can grow mold and bacteria.

Luckily, a little DIY humidifier care can prevent a dirty humidifier from causing health problems. Read on to learn how to clean a humidifier, remove calcium buildup, and keep it working for years to come.

How Often Should I Clean My Humidifier?

The best way to clean a humidifier is often. While the combination of stagnant water and heat might increase your indoor humidity to comfortable levels, the humidifier itself is an ideal breeding ground for bacteria.

How to Clean a Portable Humidifier

Most portable humidifier manufacturers include specific cleaning instructions for each model. If you can’t find your owner's manual, there are some general best practices for how often to clean a humidifier:

  • Daily cleaning – Remove the water tank, rinse it, and let it air dry after every use. This is the best way to prevent stagnant water from supporting bacterial growth.
  • Weekly cleaning – Especially if you use your device only a few days per week, give the tank a thorough cleaning at least once per week. Disassemble removable parts and scrub with water and vinegar. (We’ll discuss this more later!)

How Do I Know If My Humidifier Is Dirty?

Regular cleaning prevents common signs of a dirty humidifier. You may need to give your device a deep clean more often if you notice:

  • Reduced performance, or less mist than normal
  • Mold or mildew growth
  • A bad odor
  • A calcium buildup
  • A scale buildup

If you notice any of these issues, stop using your humidifier until you can give it a much-needed deep clean.

Can a Dirty Humidifier Make You Sick?

Absolutely, which is why regular cleaning is so important. Continuing to use dirty humidifiers can cause health problems. In most cases, this amounts to coughing, sneezing, or allergy and asthma flare-ups—but that’s not the worst of it.

Humidifiers have also been linked to severe flu-like symptoms, lung infections, and even Legionnaires’ disease.

How to Clean a Whole-House Humidifier

About 4% of homeowners have a whole-home humidifier. Also known as furnace humidifiers, these appliances are connected to your home’s HVAC stack and are controlled by your thermostat to increase moisture levels.

Whole-home humidifier cleaning is more involved but required much less often. Many homeowners rely on annual or semi-annual humidifier cleaning as a part of their regularly scheduled HVAC maintenance appointments. To schedule your annual heater, heat pump, or furnace maintenance appointment, contact your local One Hour Heating & Air Conditioning®.

If you care to DIY, first, you’ll need to identify which type of whole-home humidifier you have. There are two common systems: drum-style and flow-through humidifiers.

Cleaning a Drum-Style Whole-Home Humidifier

Most homes have a reservoir or “drum-style” humidifier, which uses a float-controlled pan filled with water that keeps an evaporator pad moist. This type is more prone to stagnant water issues; some owners drop special tablets into the tank to mitigate bacterial problems.

How to Clean a Drum-Style Humidifier:

  1. Unplug the furnace or turn it off at the breaker to avoid electrocution hazard.
  2. Remove the cover and set it aside. You may need a screwdriver, but most units have a latch-style closure.
  3. Remove the drum and inspect the pad. While it’s sometimes possible to clean an evaporator pad by scrubbing it with vinegar, we typically recommend replacing the pad to avoid respiratory problems. Take a moment to wipe the drum using a rag and a 1:3 ratio of water and white vinegar.
  4. Reinstall the drum with a new (or cleaned) evaporator pad and make sure the water level is correct. The drum should dip into the water reserve with every rotation and completely submerge below the water line. Put the unit’s cover back on securely. You’re almost done!
  5. Turn on the furnace at the switch or breaker. Give the system an hour or two of runtime and monitor humidity levels. A functioning whole-house humidifier should keep your home’s humidity around 60%.

Cleaning a Flow-Through (or Drip-Style) Whole-Home Humidifier

Also known as a drip-style humidifier, flow-through models channel water from a nearby line onto a special plastic or metal evaporative screen pad to introduce moisture into the heated air from the furnace. These units control humidity levels with a device called a humidistat, which adjusts humidity levels in much the same way your thermostat adjusts to temperature changes. Flow-through humidifiers are typically more expensive but less prone to bacterial growth, mold, or mildew.

How to Clean a Flow-Through (or Drip Style) Humidifier

  1. Unplug the furnace or cut power at the breaker panel.
  2. Remove the clips (or latches) that hold the feed tube and manifold in place at the top of the humidifier. The feed tube should be removable from the manifold. Then, remove the evaporative screen pad.
  3. Clean the pad and manifold. Cleaning the pad on these models depends on the material your system uses. Metal pads are prone to calcium buildup, which may require a screwdriver or chisel to remove completely. Mix a 1:3 solution of water and vinegar and soak the pad until it’s clean. Be sure to rinse the pad thoroughly in water—you may need to soak the pad a few times to get it completely clean.
  4. Replace the evaporative pad, manifold, and feed tube into the humidifier and reinstall the cover. Restore power to the unit and allow the system to run for an hour or two. Check your home’s humidity levels to ensure everything works properly.

One of the most common issues with flow-through humidifiers is the humidistat. Troubleshooting humidistats often requires a multimeter or voltmeter to check if the device is getting adequate electricity. Due to the risk of electric shock, we strongly recommend contacting a trained HVAC technician to address humidistat problems.

Health, Comfort, and Humidity Go Hand-in-Hand: Humidifiers Make it Possible

Humidifiers are beloved HVAC appliances that positively impact your home’s comfort and health. The technicians at your local One Hour Heating & Air Conditioning® have the resources and experience to maximize whole-home humidifier benefits, all while performing quality work backed by our 100% satisfaction guarantee.

For expert humidifier service and support, find a location near you or call (800) 893-3523 today!