If you're reading this, you're probably familiar with the H2O Cordless Humidifiers (that's the brand I sell), as they make some of the cheapest cordless plant humidifiers available on the market, making them a popular choice for houseplant hobbyists who want to save their pennies for more plants.
But no matter what brand your plant's humidifier is, or how much you spent, how well you maintain your humidifier is the key to problem-free running for months or years to come.
Maintenance is key
First-up, it's important to know humidifiers can be high-maintenance little beasties. It's just the type of appliance they are.
Humidifier maintenance is much the same across all brands, although in this guide we focus on the maintenance and trouble-shooting for common smaller indoor plant humidifiers.
Some brands are much easier to maintain than others (my first humidifier was a nightmare but I find the H2O ones the easiest).
The good news is regular maintenance can extend their lifetime and help you avoid a lot of common humidifier issues...
How much do humidifiers cost?
If you're still in research mode and haven't purchased yet, you'll find the price of humidifiers varies considerably. Size, quality and what 'smarts' it comes with all factor into the price. Expect prices for smaller humidifiers to range from around $50 to $150.
Smaller capacity, corded, USB models tend to be cheaper. Larger capacity or cordless models tend to cost more. Under $100 would be considered the cheaper end of the scale. Around $150 to $300 tend to have bigger capacity, longer run-times, last longer and cover larger areas (my corded Crane humidifier was around $150). $500+ tends to be the start of the commercial and industrial humidifiers.
Before you buy a cordless humidifier...
A factor often overlooked is whether you pick corded or cordless. Unless you really need cordless, I'd go for a corded for any appliance, humidifiers included.
Just being cordless can count for a big chunk of the price because of the cost of the battery alone, but the battery is also a common reason a cordless appliance can have a shorter life than corded.
You'll usually get higher quality, longer-life appliance by avoiding appliances with a rechargeable battery. A bit like mobile phones. Often it's the life of the battery that determines the life of the phone, even phones that cost hundreds or a thousand+ dollars can have a shortened life due to a battery that no longer charges to full strength, or can't hold charge for long.
Also like many mobile phones, cordless humidifiers usually don't have replaceable batteries, so once the battery has reached its lifetime, you'll need to replace your entire humidifier.
And because humidifiers are often stored between seasons, unlike a phone in regular daily use, storage can also shorten the life of the battery (more about that coming up).
How often should you clean a humidifier?
Think of your humidifier like your shower. Most brands recommend a weekly clean.
If left too long, mineral salts, fungi, algae and bacteria can work their way to areas of your huidifier that you CAN'T clean, causing avoidable problems with your humidifier later on.
These days I mainly use the H2O plant humidifiers for my plants. They might not be the fanciest or longest-life humidifiers, but they look great and the price is really good considering they are cordless. Plus being more simple, without a lot of bells and whistles of more expensive humidifiers, I find that makes the H2O brand easier to keep clean too.
What should you clean a humidifier with?
You have lots of options for cleaning your humidifier. The most common are white vinegar, citric acid, bleach, hydrogen peroxide or a descaler like CLR.
Although white vinegar is the weakest of the four options, provided you give your humidifier a clean frequently (every week), it will do the job just fine.
I did find with my Crane humidifier I had to use bleach about monthly (reluctantly), but it had more smaller, fiddly parts to clean than most.
You can use white vinegar from full to half strength. I ususally use 50/50 white vinegar to hot water for mine but occasionally use it neat. Here's the general way to clean any humidifier, best done weekly...
How do you clean a humidifier?
1. Empty and take it apart
Unplug / turn off your humidifier. Empty any water out. Take everything apart (parts that should be taken apart of course).
You'll usually end up with the top separate from the base, wicks out, wick covers off, wick springs out. Those parts vary depending on the model you own.
The parts that produce the mist will usually be housed in the top or the base and you don't need to take apart or access that area. That part of your humidifier should also never be cleaned by submerging under water, so stick to wiping it down on the outside with your cleaning solution, not soaking, to avoid water getting in to the electronics during cleaning.
Also avoid getting anything in the mist outlets (even including water). Water that pools then dries in the mist outlets can leave behind mineral deposits (limescale) that builds up over time and block the outlets.
When removing the wick cover/s, filter pad/s or filter wick/s, you may find your humidifier has a spring in the bottom wick cover. That pushes the wick in contact with the atomiser. Don't lose the spring! Put that carefully aside. The spring shouldn't need cleaning.
2. Soak and scrub
Fill the water reservoir back up with your choice of suitable cleaner. Soak the filter pad, filter wicks and wick covers in the same solution. Soak for about 60 minutes (or longer), depending on what level of cleaning is needed.
After soaking, use an old toothbrush or similar to gently scrub all hard surfaces, such as the sides and base inside the water reservoir, and inside the wick cover or filter cover.
Most humidifiers are made of plastic, so you don't want to use anything that might scratch it, especially if your humidifier reservoir is clear. I find cotton ear-buds handy for cleaning any fiddly areas.
Once everything's been scrubbed, tip out the cleaning solution, rinse everything well with hot plain water, and wipe clean.
3. Air dry
Just like showers and sinks, being constantly wet makes a humidifier the perfect breeding ground for bacteria and growing fungi and algae.
The same pink or yellow mould and gunk you might notice in other areas of your home, like showers and around plug holes, can live in your humidifier too if not emptied and cleaned regularly.
It's important to give your humidifier a chance to fully dry out about every week or so. I find it easiest to do weekly when you're cleaning it. Even better, put it out in direct suunlight. The UV helps kill off any nasties.
That's all there is to it really. However if you've bought your humidifier second-hand, or been a bit neglectful with the maintenance and it's having issues, you may need to use bleach to kill the bacteria, or descaler to get rid of stubborn mineral deposits. More to help with problem solving below...
Never store a humidifier with water in it
Always store your humidifier dry when not in use and between using.
When refilling, always tip out old water and refill with fresh water every time to reduce mineral deposits building up (which are far harder to get rid of than a bit of mould!).
How often should the filters / wicks be changed?
Humidifiers usually come with replaceable filter pads, filter cartridges, or wicks that act as a filter. This is often the only part that requires replacing.
Over time these will become blocked (that's what they're made to do). They help filter out contaminants such as dust, smoke and excess minerals in the water.
How often you should change those depends on the model, but most humidifier filters last from 1 to 3 months, longer depending on how often you clean them, air and water quality.
Dusty or smoky environments, being used with essential oils, and hard water, can all shorten how long a filter will last before it can no longer stop those contaminants from getting in to the motor. By ten it may be too late.
It's important to check and change the filter regularly. If your humidifier has a white or light coloured pad or core, you will see that slowly change colour from yellow to brown over time as it becomes more blocked with absorbed contaminants.
Usually wherever you bought your humidifier from, will also sell humidifier wicks or replacement filter pads (I sell replacement wicks for the H2O brand of humidifiers, but if you know the size you need, the ones I sell may fit yours also).
Trouble-shooting humidifier problems
Humidifier not producing mist ot mist output low
This is the most common issue with an older humidifier but can happen anytime.
- Firstly, give your humidifier a thorough clean (see the steps above).
- If your humidifier is cordless, check the battery. Charge if needed. Do not overcharge (most cordless humidifiers should be fully charged in 3 hours). There is usually a charge indicator on most humidifiers. It should change from flashing to solid, or change colour to confirm the battery is reaching full charge.
- If your model of humidifier runs corded and cordless, try running your humidifier while plugged in instead of cordless, to check if the battery might be the issue.
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Check the water level in the reservoir is not empty. If your humidifier has an auto shut-off (usually a metal probe that sits in the water), check the probe is covered by the water. Remember to never top-up the water. Always tip out and fill with fresh water to reduce mineral salt build-up (limescale).
- Check the cord. Check both ends of the charging cord are plugged in correctly and seated firmly in place. Look for any damage anywhere along the cord. If the cord has any damage or the ends are not fitting properly, stop using it and try a new cord.
- Try a different wall plug then try a different adaptor plug, and test again. Sometimes your adaptor plug is not rated high enough to fully charge the battery, leading to low or no mist output, even when the light setting works.
- Check the wick/s. Check both ends are wet. Check if the ends are discoloured, blocked or frayed. Check the wick is not bent. If discoloured or bent, try a new wick (soaked it first).
- Flip the wick/s over and see if it starts producing mist (which suggests the wicks were not fully saturated top to bottom). Soak the wicks fully submerged in water for half an hour and try again, provided the wick does not need replacing.
- Check the spring. Deepnding on the brand, humidifiers often have wick springs in the bottom of the wick covers. If the spring is missing, find a spring or something similar (ballpoint pens often have a spring inside them and stationery, hardware and craft stores stock small springs). The spring pushes the wick up in contact with the metal disk at the top. If everything else is okay but there's no spring, your humidifier won't produce mist or may produce very little mist or start then stop producing mist.
- Clean the wick if the wick isn't new but hasn't been cleaned in a while. You can give the wick a 60 minute soak in a 50/50 hot water and white vinegar solution to help loosen dirt and mineral salts. After soaking, rinse well, let the wicks air dry, soak again in plain water, and test.
- Replace the wick/s if you haven't in the last 3 months.
Check water is not pooling in outlets
Avoid water pooling in the mist outlets. The water later evaporates, leaving mineral salts behind (limescale), which can partially or fully block the mist outlets.
If you notice water droplets on surfaces, or water pooling when running your humidifier, turn it off.
Use a hygrometer to check the humidity level before running your humidifier, and run your humidifier at the lowest mist setting needed, only when needed, to increase humidity to a better level for your plants.
Check airflow
Humidifiers are best used in well ventilated rooms, not in enclosed areas with minimal or no air flow. Used in closed environments, such as inside a grow tank, grow tent or cabinet, can shorten the life of any humidifier.
Many people do use humidifiers this way though, so if you do just keep in mind you may need to replace your humidifier more often.
In general, use the smallest humidifier you can on the lowest mist setting required for the space needed to help extend its lifetime.
Watch out for limescale
If you notice a white powdery coating or build-up in some areas, often on the top of your humidifier, especially around the mist outlets, or a fine almost salt-like build-up around the mist outlets themselves, the outlet/s may be blocked by mineral deposits.
These form over time due to the minerals found in tap water, usually from calcium or magnesium, and is called limescale.
These are the same cause of white droplets and build-up on shower doors, inside kettles, on glass and other areas frequently in contact with tap water or in high humidity areas. Limescale is also why shower heads become blocked over time.
Limescale can be difficult to remove. Prevention is the best way to avoid this.
A wipe or soak with a descaler like CLR might remove the build-up, provided it hasn't already got to areas you can't clean.
6 ways to avoid limescale in humidifiers
1. DO a regular weekly clean.
2. DO store the humidifier dry.
3. DON'T leave water sitting in the reservoir when not in use.
4. DO tip out old water and fill up with fresh water every time you refill the reservoir.
5. DO replace the filter pad or filter wick every 1 to 3 months (check what the suggested frequency is for your model as it does vary).
6. DO run your humidifier only when required, and on the lowest setting needed, to prevent water pooling in the outlets.
Remember the harder your water (meaning it has a higher mineral content), the more important a frequent clean and regular filter replacement becomes. It's important not to run your humidifier if it's not producing mist, as if the cause is blocked mist outlets, you may otherwise burn out the motor and cause irreversible damage.
If that all sounds rather dire, remember prevention is easy and the best way to avoid this happening in the first place. Most humidifiers are made to be used with tap water, provided you follow correct maintenance and care.
Cordless humidifier running corded but not cordless
Provided your battery hasn't reached the end of its lifetime (even the battery of a $1000+ iPhone will eventually reduce then stop holding charge), this is usually an easy fix.
It may be caused by the cord, charger or plug. Try changing each thing, one at a time, and test as you go. Try using a different wall plug. Try directly plugging in to a USB port on a computer. Try using a different cord. Try a different USB adaptor.
If you've had your humidifier a while and the battery has reached the end of its lifetime, then it's likely time for a new humidifier, unless your model has a removable battery you can replace (most humidifiers don't). Or you can of course just keep using it corded instead of cordless.
How to store a humidifier
If your humidifier can run cordless / has a rechargeable battery:
Never store a rechargeable battery on empty. Charge the battery to around 40% before putting it into storage. If your humidifier doesn't have a charge indicator, use it until the battery runs out, then charge it half the usual charging time.
Most rechargeable humidifiers use lithium ion batteries. If stored empty or with a low charge that runs out when in storage, the battery may not hold a full charge later, or may charge but not run the full amount of time, or may not charge at all (batteries discharge small amount of charge even when not in use which is why they should be stored with a low level of charge).
Recharge every few months
If storing for more than 2 months, take your humidifier out of storage every couple of months, discharge and recharge the battery to about 40% before returning to storage.
Clean before storing
When water evaporates it leaves mineral salts behind which can turn hard and block the humidifier. Give the humidifier a thorough clean (check the cleaning directions above) to get rid of any excess salts before storage.
Avoid extreme temperatures
Extreme temperatures (heat or cold) can shorten a batteries life and also cause damage. Avoid storing in direct sun or very cold temperatures. Best stored at room temperature indoors, not outdoors, not in a vehicle etc. If your humidifier has removable batteries, you can also remove and store the batteries in the fridge (not freezer).
Check the warranty
Another reason regular maintenance is important is because issues caused by external factors like limescale are not normally covered by warranties. That is ofte considered either wear and tear or preventable / avoidable.
Like most warranties, only faults or defects with the appliance itself are covered, which normally excludes issues caused by external factors or by the user (whether by accident or not).
Also note the length of a warranty gives you a good hint to the quality and expected lifetime of any appliance. 12 months is standard for higher quality or more expensive appliances likely to last for more than a year.
You might get 2 or 3 year warranties with something like a new car, but cheaper appliances tend to either not have a warranty, or to be limited to a 3 or 6 month warranty.
In New Zealand the Consumer Guarantees Act usually applies also, although there can be a few limitations there also so it's worth reading up on your rights.