Is my room humidifier making me sick?

Last Updated on 1 year by Christopher G Mendla

The answer to the question “is my room humidifier making me sick?” could very well be a resounding “Yes”. During the winter many homes need additional humidity, especially homes with forced air heat. Ultrasonic and steam humidifiers are a popular way to increase humidity. However, even with careful cleaning, they can harbor algae, slime and bacteria. 

Overview – Using ultrasonic humidifiers to increase humidity

For the last couple of years, I was using ultrasonic room humidifiers to try to keep the humidity at a decent level during the winter months. I finally got far enough down the chore list to replace the spray humidifier on my furnace. That provided enough humidity that I could clean and mothball my ultrasonic humidifiers.  I also used a home humidifier hack consisting of a wet towel and fan. That actually worked well. 

According to the Mayo Clinic,  proper humidity will ease breathing and skin problems. 

Below is an example of an ultrasonic humidifier. I have two of this size (about one gallon)  and a larger unit that holds about 2 gallons. 

The units worked fairly well although they didn’t get the average humidity above about 35 percent. The spray unit on the house gets the humidity about 15 percent higher.  Note – I do not run the unit on a vintage wood table. I just put it there to photograph it. 

WARNING – read the instructions and warranty for your units as improper cleaning could void the warranty or cause other issues. This is just an example of how I cleaned my humidifiers.

Downsides to room humdifiers

The first downside is the need to constantly refill the units. I generally had to refill all three units about 3 times every two days. With the ‘eco friendly’ slow drip faucets, that became time consuming.

They also need to be cleaned regularly. I found that my units had to be thoroughly cleaned at least once a week. Twice a week would be better.

Scum would build up in the reservoir and in the tube inside the tank as well as the bottom of the tank. This brand used a silver impregnated tank that did a good job of keeping the water in the tank clean. Ideally, a thorough cleaning once a day would be best but is impractical for most people.

However, there was always a ‘soap scum’ waterline and also a pink stain. The pink stain is an airborne bacteria which appears to be Serratia marcescens. According to the Wiki article linked, it could be nasty.

Cleaning the units every day was simply not manageable as it takes about 15 minutes or so to properly clean each one. I opted to clean once a week.

While this post details cleaning an ultrasonic humidifier the same concepts apply to evaporative and steam humidifiers.

Cleaning a room humdifier

The cleaning procedure was pretty simple:

• Empty all the water
• Spray all surfaces with straight vinegar. SEE THE WARNING ABOVE ABOUT WARRANTIES. I’d let the vinegar sit for a bit and then respray. Be sure to get all of the crevices. 
• Use the provided brush to clean the ultrasonic button. Then use Q Tips wet with vinegar to clean into the crevices. 
• Wipe down as much as possible with a vinegar soaked paper towel. 
• Soak some parts such as the nozzle in bleach. 
• A steam cleaner can help kill any algae or bacteria but you risk damaging the unit. 

Cleaning difficulties

Cleaning is a bit difficult in that the humidifiers have a lot of crevices. Getting inside the tube to clean is difficult unless you have a bottle brush set aside for that purpose.

You need to be careful with using something like Clorox as it could have an adverse affect on the ultrasonic button.

Close ups of the algae and bacteria.

I wanted to do a thorough cleaning before setting the units aside. Hopefully, I won’t need them but if I do, they will be clean.

Below is the water tray. To the left is a float valve and to the right is the ultrasonic button. I only used the nylon brush that was provide with the unit to clean the button. For the float valve, I would lift it and try to get under it with a Q Tip.

If you look closely, you can see the “Bathtub Ring”on the walls.

Below is a shot of the inside of the tube. This is the tube that runs through the water reservoir and delivers the mist. It wasn’t quite as bad as it looks here. Shooting inside the tube was tricky. However, there was a noticable sheen of algae in the tube. This required a couple of runs with a bottle brush and vinegar to remove.

The image below is zoomed in on the white plastic that is joined to the blue water container. The joint is difficult, if not impossible, to clean. Carefully spraying bleach will get most of the crud and algae. 

The image below indicates a fundamental failure of the units. The pink residue is airborne bacteria. The design has crevices that are nearly impossible to clean. Using bleach or other cleaners could damage the ultrasonic button. 

Shown below is the nozzle that fits on the top of the tube. Algae and bacteria grow inside the nozzle. In this case, the parts can be separated so that you can clean the inside. However, many people might not think to do that. 

Conclusion and alternatives to room humidifiers.

If you are purchasing a unit, take a close look to see how easy it will be to clean. Check the owner’s manual online to see if you can use bleach to clean the unit.

Consider installing a whole house furnace humidifier if possible. If you have radiators, this will not be an option.

The hack referenced at the beginning of this article is a good temporary solution.

If you do use a room humidifier, set a strict schedule for cleaning and be sure to get into every nook and crevice.

A similar problem is when room air conditioner filters are dirty.