Choose the routine for your humidifier
- For a portable humidifier, unplug it, empty it and remove scale and film every third day.
- Choose the cleaner your manufacturer recommends, then rinse thoroughly before use.
- For Honeywell Home TrueSteam or Steam-branded units, use the bucket-and-drain procedure below.
If you're looking at crust inside the tank, we'd start with the humidifier's cleaning-product directions before choosing a chemical. The right product depends on those directions, and removing scale matters because it can provide a breeding ground for microorganisms.
First, separate the portable-unit routine from whole-house maintenance. Portable humidifiers are smaller and readily moved, while central humidifiers are built into your heating and air conditioning system. That distinction changes which cleaning procedure you should follow.
What the crust and film mean
Minerals in tap water can form crusty deposits inside a humidifier. Those deposits are scale, and removing them addresses more than appearance: scale can support microorganism growth. Film on the tank walls and deposits on other interior surfaces also belong in the cleaning job.
Standing water creates another concern. Microorganisms often grow in humidifier tanks that contain standing water, and ultrasonic and impeller units can send microorganisms and minerals from that water into your indoor air. Keeping the tank clean and changing its water serve different parts of the same care routine.
Evaporative and steam-vaporizer humidifiers generally disperse less of these pollutants, but their tanks can still support microorganism growth when water stands in them. An evaporative unit uses a fan and damp absorbent material, such as a wick, while a steam vaporizer heats water. Warm-mist humidifiers are steam vaporizers that cool the steam before it leaves the machine.
Brush away portable-tank buildup
Set a recurring cleaning reminder for every third day for your portable humidifier. This schedule reduces the buildup of scale and microorganisms, so cleaning belongs on the calendar even when you aren't dealing with a thick layer of crust.
Unplug the unit from the electrical socket before you begin, then empty the tank. Use a brush or other scrubber to remove scale, deposits and film from the tank sides and interior surfaces. Give the interior the same attention as the tank walls: the cleaning target includes both.
Look over the surfaces you've cleaned for remaining deposits or film. The visible result you're aiming for is removal of that buildup, with all surfaces wiped dry at the end of the cleaning process. If you're using a cleaning agent during this job, complete the rinse described next before the final wipe.
Choose a cleaner and rinse it away
Check your humidifier manufacturer's recommendations for cleaning products and disinfectants. Those recommendations come first. When there are no specific recommendations, use a 3% hydrogen peroxide solution to clean all surfaces that come into contact with water.
The fallback applies to water-contact surfaces throughout the humidifier, not only the most noticeable patch inside the tank. Keep the product decision tied to your particular unit, especially when moving between a portable humidifier and a central system with its own maintenance directions.
After using any cleaner or disinfectant, rinse the tank thoroughly with several changes of tap water. Cleaning chemicals left behind can be dispersed into the air during use, which makes rinsing part of the cleaning job itself. Use fresh rinse water for each change.
You can keep the EPA's care instructions (opens in a new tab) handy for the portable routine and its cleaning-product fallback.
Fresh water is a daily job
Between full cleanings, give your portable humidifier fresh water daily to reduce microorganism growth. Unplug it first, empty the tank, wipe all surfaces dry and then refill it. The daily routine includes drying the surfaces as well as changing the water.
Keep daily water care and every-third-day cleaning as separate reminders. The daily job deals with the water and wet surfaces, while the fuller cleaning removes scale, deposits and film. Both belong in the routine for a portable unit.
If yours is a console humidifier, the cabinet-style kind designed to sit on the floor, follow its manufacturer's instructions for changing the water. Its water-changing directions take precedence over transferring the portable routine to it.
Refill with lower-mineral water
For the portable unit's refill, choose water with low mineral content. It helps prevent both scale buildup inside the humidifier and mineral dispersal into the air. Bottled water labeled “distilled” is a documented option and will likely contain fewer minerals than most tap water, although it still contains some.
Read the water label before buying a bottle for this purpose. Water labeled “spring,” “artesian” or “mineral” hasn't been treated to remove mineral content. Bottled water isn't a single category when your goal is to reduce the minerals going into the tank.
“Purified” water can come from distillation, deionization, reverse osmosis or similar processes. Deionization and reverse osmosis remove most minerals, but they're generally less effective at that than distillation. On average, water treated by those two methods would be expected to retain more minerals than distilled water.
If you've noticed white dust on nearby surfaces while using an ultrasonic or impeller humidifier, minerals in its water can explain it. These types disperse tap-water minerals efficiently. Steam-vaporizer and evaporative units aren't expected to disperse substantial amounts of minerals, although mineral buildup still belongs in your cleaning checks.
Clean a Honeywell Home TrueSteam or Steam bucket
For a central, furnace-mounted humidifier, follow the manufacturer's cleaning and maintenance directions. If it has a tank, keep the water clean and don't leave it standing for extended periods. The bucket-and-drain instructions below apply specifically to Honeywell Home TrueSteam or Steam-branded humidifiers.
Remove the bucket and clean debris and scale out of it using vinegar or CLR. The result to look for is a bucket cleared of that debris and mineral buildup.
Next, inspect the drain line for both cracks and debris. If it needs clearing, flush it with vinegar or CLR to remove the debris. A clear line and a damaged line lead to different next steps, so check its condition as well as whether the debris has cleared.
When the drain needs professional attention
If the drain line is cracked or you can't clear it, have it replaced. Contact a licensed and certified HVAC contractor for that work, and leave all other service and checks to that contractor.
Use Honeywell Home's maintenance page to find its professional-contact option (opens in a new tab). When you contact the contractor, describe whether you found a crack or debris that remained after flushing.
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