Best Auto Filling Humidifier For 2021

Suffering from asthma attacks, seasonal allergies, as well as dry, cracking skin in the winters, I learned the true value of a humidifier for indoor air quality early on.

However, since I tend to run these machines for seriously long periods, especially during colder months, I was never a fan of the hassle that came with frequent refilling. So when I came across auto-filling humidifiers, I knew I hit the jackpot!

Today, I’ll be helping you find the best auto-filling humidifier for your needs with reviews of the top 4 products on the market as well as a detailed buying guide.

Table of Contents

What is an Auto Filling Humidifier?

In dry conditions, the lack of moisture in the atmosphere of your house causes the air to look for an alternate source of moisture to increase its level of humidity. Consequently, dry air can cause moisture to evaporate from our skin and mucous membranes that line our respiratory system.

This can lead to an array of problems including dry skin, dry throat, coughing, irritated eyes, cracked lips or skin, as well as triggering or worsening the symptoms of allergies and asthma.

Enter air humidifiers – these are machines designed to give out water vapor or steam, consequently increasing humidity or moisture levels in the air.

In other words, instead of drawing moisture from your skin, nose, or lungs, humidifiers will provide dry air with an alternative source of moisture. This, in turn, helps prevent health issues caused by dry air (along with the administration of medication if needed).

So that’s what a humidifier is, but what about the “auto-filling” part? Well, to explain this, allow me to get a bit technical.

Humidifiers come with a tank that holds the water which will be turned into mist or steam. As you let your humidifier run, the amount of water in the tank will gradually decrease.

Once the water level reaches a certain low, you’ll have to refill the tank so the humidifier continues to work properly. If you’re anything like me, then you constantly have this thing on throughout the winter which can be a true nightmare when it comes to refilling. You’ll probably need to refill your humidifier every day, or even twice a day.

Obviously, such a high refilling frequency can be a hassle to deal with between being busy and being forgetful. This is where the auto-filling feature comes in handy, providing humidifiers with a way to automatically refill from a nearby water source.

Not only are auto-filling humidifiers much more convenient for those with hectic schedules, but they also save normal folks a lot of time and effort.

What are the Types of Auto Filling Humidifier?

There are mainly 6 types of auto-fill humidifiers you can find on the market, each with a different mechanism of transforming water into vapor or steam. Here’s a breakdown of these types:


  • Central humidifiers – these machines are built into the main air conditioning and heating system of your house. They’re designed to humidify air throughout the entire house.
  • Ultrasonic humidifiers – these devices utilize high-frequency ultrasonic vibrations to produce an extra fine cool mist. In general, they’re considered the quietest type of humidifier – ideal for households with babies or pets.
  • Steam vaporizers – this type of humidifier uses electricity to boil water via a heating element, releasing steam into the room for added moisture.

If you have kids or pets in the house, having a device that produces hot steam around the premises isn’t very safe due to the risk of burns. In this case, you’ll want to place it somewhere that’s hard to reach.


  • Evaporators – these humidifiers use built-in fans to blow air under high pressure through a wet wick, belt, or filter. This will turn the liquid water into vapor without the need for heat.
  • Impeller humidifiers – these machines utilize a rotating disc, running at a high speed, to fling water at a built-in diffuser that breaks it into fine droplets. These fine droplets will then float into the air in the form of a cool mist.

Key Considerations When Buying an Auto Filling Humidifier

Choosing the right humidifier for your needs mainly depends on the size of the space you’re looking to humidify. Additionally, there are several features that you should first consider before making a purchase to ensure maximum convenience.

Size of Room and Humidifier

The size of the room you want to humidify plays a key role in deciding the suitable humidifier size to effectively accommodate such space. In turn, the size of the humidifier determines how much water it can hold, how long it can run, where it can be placed, as well as how easy you can relocate it

If your goal is to humidify multiple rooms, offices, or your entire house, then you should consider medium or large-sized humidifiers, often called console humidifiers or whole house humidifiers.

These machines offer significantly powerful performance where some units are capable of delivering moisture across spaces as big as 3000 square feet. They’re usually placed on the floor as their weight can get too heavy for a shelf or a table.

Additionally, console humidifiers are equipped with larger and wider atomizer plates (the component that turns water into mist) to quickly disperse moisture across multiple rooms of a building.

As for small and medium-sized spaces, a tabletop or room humidifier is probably your best bet. Such auto-filling humidifiers are designed to be more compact and easy to move from one room to another.

Either way, you should be very careful when deciding the suitable humidifier size. If you end up with a humidifier that’s too big for the target space, it can lead to moisture condensation on surfaces like tables and windows, which encourages mold growth.

Tank Capacity

Another important factor to consider when shopping for an auto-filling humidifier is the tank capacity. The larger the water holding capacity of the tank, the longer the humidifier will run per single refill.

Most small and medium-sized humidifiers typically include tanks with capacity ranging between 200 to 300 milliliters, which allows them to run continuously for about 8 to 12 hours before having to refill.

Larger humidifiers, on the other hand, usually have tanks with capacity ranging between 1 and 6 liters. This can take around 20 to 60 hours to empty, and your humidifier won’t have to refill itself as frequently.

Remember, a larger capacity doesn’t necessarily translate into a bigger humidifier. Some humidifiers have a compact physical appearance yet their tanks are rather wide. So be sure to check the water holding capacity mentioned in the description of the humidifier.


Not all auto-filling humidifiers support a timer feature, but the ones that do are regarded as highly convenient. A timer allows you to set the humidifier to run for a certain period after which the machine will automatically shut off. This deems the unit more energy-efficient because it’ll stop working when you don’t need it to.

Mist Adjustment

If you want to be in control of how much mist your humidifier releases into the environment, then you should make sure it comes with a mist adjustment button or knob. This will also let you decide how fast or slow you want to raise the humidity level of the room.

Reviews Of The Best Auto Filling Humidifier

1. YUKI Automatic Filling Humidifier XXL

First up, the Automatic Filling Humidifier XXL by YUKI is exactly what it sounds like – an auto-filling humidifier built to deliver moisture for medium to large-sized spaces. It humidifies up to 2000 cubic feet, which makes it ideal for spaces starting from 500 square feet.

This humidifier is equipped with a self-filling valve so you can connect the machine to a water line, from which water will be drawn for automatic refilling. It runs at an output capacity of 12 gallons per day, which is more than enough for the average household.

The YUKI Automatic Filling Humidifier XXL has a unique design that features a wood-like finish with black accents. Both reliable and stylish, this machine measures at 14″ L × 22″ W × 24″ H dimensions. It’s not the most compact model on today’s list, so make sure you have enough space to set it up.


On a positive note, this auto-filling humidifier comes with digital controls for easy adjustment, a 4-speed fan for flexible programming, as well as an automatic shut off function to prevent damage and save energy.

As an auto-filling unit, this humidifier doesn’t have any refillable tanks or fill hose. But if you buy it while you’re still getting a water line connection ready, you’ll be able to add 2 gallons without overflow.


  • Reliable operation
  • Stylish design
  • Accepts 2 gallons of water in the absence of a water line
  • Great customer service


  • A bit bulky

Offering a versatile fit to serve more jobs, the Honeywell HE300A1005 True Ease Advanced Evaporative Humidifier can be a wonderful addition to your home. As you can probably tell by the name, it utilizes evaporative humidification to circulate moisture throughout your house.

It relies on a fan-powered operation where a built-in internal fan draws warm air from your HVAC system then pushes it back into the system. This makes the HE300A1005 both efficient and simple to install with quick snap bypass direction adjustment.

The unit also features HumidPRO Digital Humidity Control that automatically monitors the level of humidity in your home and triggers water evaporation accordingly. This machine can produce up to 18 gallons per day, covering spaces as large as 850 square feet.

Moreover, the HE300A1005 auto-filling humidifier comes with a timer metered solenoid that reduces water waste by 30%and up to 50%. With its low maintenance demands and operational noise reduction, this reliable unit is definitely well worth the money.


  • Energy efficient
  • Automatically monitors air humidity level
  • Quiet operation
  • Low maintenance



Showing off thousands of positive reviews, the Aprilaire 500 Whole-Home Humidifier is manufactured in the USA by a leader in indoor air quality solutions.

This particular model is pretty much identical to the company’s popular 2009 model – the Aprilaire 500A – but the newer version doesn’t come with a second water panel or a DVD video.

However, the 500 auto-filling humidifier includes the staple feature of almost every Aprilaire unit; the automatic humidifier control that works simultaneously with a furnace. This allows the unit to sense the ideal time for changing the air humidity level to ensure maximum comfort.

Running at an evaporative capacity of 12 gallons per day, this humidifier is also an excellent choice for covering spaces up to 3000 square feet in tightly built homes. It’s even available in 4000 and 4200 square feet options for larger households.

Moreover, the Aprilaire 500 is extremely quiet so you shouldn’t encounter any noise-related issues. This auto-filling humidifier has a manual control panel, but you can also buy it with an automatic digital panel.


  • Accurate humidity sensor
  • Compact design
  • Very quiet
  • Budget-friendly option


  • The moisture output capacity can be improved

Last but not least, the HE280A is another reliable auto-filling humidifier by Honeywell. It’s a remarkably powerful unit that’s also compact and affordable, making it a great option for shoppers on a budget.

Similar to most other Honeywell humidifiers, you’ll also have to install the HE280A with a furnace. The installation process isn’t exactly easy, but the humidifier does come with an installation kit that includes all the components you need to set it up.

Moreover, it’s extremely low maintenance, so once you get it up and running, all you have to do is simply change the humidifier pad once a year or so. The HE280A auto-filling humidifier also features a water-saving technology that utilizes 30% less water than conventional models.

It’s capable of delivering moisture throughout an area up to 4000 square feet, making it suitable for most households. The shut-off damper and flow-sensing pressure utilize your home’s HVAC system, which helps make the installation a bit easier.

The included controls are straightforward so you can figure out how to adjust the humidity levels right away. With a compact design that’s a breeze to clean, the Honeywell HE280A surely deserves a spot among the best auto-filing humidifiers.


  • Comes with installation kit
  • Save up to 30% more water
  • Easy to clean
  • Outstanding value for money


  • Installation is rather tricky

Wrap Up

Choosing the best auto-filling humidifier can get confusing, especially with features like size and capacity to look out for.

However, if I had to name a winner, then the Honeywell HE280A Whole-Home Humidifier would take this one home. It offers coverage for spaces up to 4000 square feet large, which works for just about any average home. It’s also compact and quiet, so it won’t disturb your home in any way.

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