Aprilaire 400 vs 600: Which Humidifier is best ?

When you are looking for an air filtration system, you need to know what important features to look for. When it comes to Aprilaire 400 vs 600 there is a lot of bad and false information floating around. The Aprilaire 400  and the Aprilaire 600 are two of the most popular whole house humidifiers used in forced-air heating systems. Both of these humidifiers are well-rated with most homeowners and contractors enjoying their results. This blog will compare both the Aprilaire 400 and the Aprilaire 600 so you can make a more educated decision on which humidifier is right for you

For some of us who are looking forward to some extra moisture and heat this winter, the Humidifier might seem like a luxury we don’t have. After all, how many of us can walk around with a humidifier?
With all the different kinds of humidifiers on the market, it can be challenging to know which one is right for you. Are you looking for a humidifier that will help keep your home cool, while not keeping moisture out? Or do you prefer something that is machine-based and can be set up easily?
If you answered ‘both’ to the last question, then chances are you are looking for an Aprilaire’s 400 or 600 Humidifier. Because we’ve found a few reasons why you should consider an Aprilaire Humidifier instead of a common humidifier.

Aprilaire 400 vs 600 Specifications:

What is a Humidifier?

A humidifier is a device that, when set up correctly, will maintain a specific humidity level in the air at all times. There are many types of humidifiers and people are divided on which type is best for each user. The goal of a humidifier is to keep the air in your home at a certain humidity level so that it is less likely to become too dry or too sticky.
A common setting is 37% to 47% relative humidity.

Aprilaire 400 Humidifier:

The Aprilaire 400 is designed to maintain constant humidity in your home by using a fan and a thermostat. The humidifier works well for many homeowners because it does not require humidity sensors or gauges to tell you when it is going too slow or fast. The 400 has a variable fan speed which allows you to control the amount of air passing through the humidifier. This can help protect your furniture from electrical stress, so you don’t have to worry about ruining your furniture with excess moisture
The unit comes with 4 tanks each of which holds approximately 18 ounces (500 ml) of water. These are made out of plastic and should be replaced every season or two depending on how much moisture is being generated inside the unit.

Design and Capacity

Aprilaire 400 is the most efficient evaporative humidifier that has ever been made. It is the best choice for the money. Working quietly and efficiently it consumes less energy and water than other humidifiers. Aprilaire 400 is a high quality, large capacity humidifier that utilizes advanced design and efficient, energy-conserving technology. Aprilaire 400 is designed to operate, at minimum, 24 hours per day, seven days a week, for the most efficient operation. The Aprilaire 400 is the best choice to keep your home comfortable with a high capacity water panel that works non-stop to deliver up to 17 gallons of moisture daily. Aprilaire 400 is designed to heat and distribute water through the Aprilaire Humidifier Pad. The Aprilaire 400 has the power to humidify up to 4,000 square feet.


The Aprilaire Model 400 Humidifier gives you all of the advantages of the HE20 humidifier with the ease and efficiency of the electronic digital control panel. The controls are mounted on the top of the humidifier and are easily accessible. The Aprilaire 400 is the answer for homeowners looking for a quality, low-maintenance humidifier for their home.


Your Aprilaire Model 400 Humidifier is built to last. It’s constructed of durable materials throughout, and is backed by Aprilaire’s legendary warranty. Your Aprilaire HE20 humidifier was designed to maximize humidifying efficiency and performance.


1. The humidifier comes in a sturdy and compact design.
2. It has an adjustable fan speed.
3. This unit is compatible with other filters, and the filter is easy to change – simply unscrew the old filter, screw in the new one, and then rinse off the filter in the sink.
4. This unit comes with two filters: A prefilter (from which moisture will be captured) and a small membrane (which will catch particles).

Pros & Cons

  • Easy to set up and control.
  • Offers a range of options for the fan speed with the ability to run for 30, 45, or 60 minutes at a time.
  • Maintenance and cleaning can be done easily by taking a soaked washcloth and wiping down the exterior of the humidifier.
  • Cooler air will make it feel like an additional 17°F colder which could contribute to further energy savings on your home’s energy bills.
  • The small size makes it a handy addition to any bedroom or office.
  • Provides a low noise level and doesn’t need a blower fan to run.
  • Needs constant attention to keep the humidifier working efficiently
  • Cannot be left on standby mode before being turned off. It needs to be turned off at night before shutting down. Alternatively, you can set it on ‘night mode’ which will turn the unit off after 20 minutes of no use.

Aprilaire 600 Humidifier:

When it comes to the functionality of Aprilaire’s 600 Humidifier, the machine is simple and straightforward. For those who are completely new to this kind of machine, an Aprilaire humidifier may seem to have more bells and whistles than what you are looking for. However, there are plenty of features that make this machine worth a closer look. The 600 Watt unit will offer a maximum output of 600 cubic feet per hour, guaranteeing that you will have plenty of air movement in your home.

 Aprilaire 400 vs 600
This humidifier is available in four different color options: black stainless steel with a polished bezel, grey marble with a polished bezel, white marble with a polished bezel, or silver steel with a brushed bezel.

Design and Capacity:

Aprilaire humidifiers are designed for the comfort and well-being of your family. With Aprilaire, you can be sure that your family is breathing the cleanest air possible. Aprilaire humidifiers offer a truly innovative approach to humidification, one that delivers the highest quality air while minimizing your energy bills. The Aprilaire 600 is easy to install and maintain and works in conjunction with your furnace helping to eliminate dry, heated air. With a total tank capacity of 1.5 gallons and an energy efficiency ratio of 0.93, this machine can maintain humidity levels in your home up to 30% higher than the recommended level.


The sound throughout the water tank is virtually silent, with less than 55 decibels. With adjustable humidity levels at 75%, 80%, 90% and 100%, you will be able to find the optimum setting for you with this humidifier. This unit is also available for easy use without needing a filter change every few months, with the filter lasting up to two years.


Featuring a continuous drain, it offers exceptional drainage ability and helps to keep your humidifier running for a long time. It is ideal for use with a whole-house humidifier, and compatible with all models of Aprilaire humidifiers. It’s constructed of durable materials throughout and is backed by Aprilaire’s legendary warranty.


1. A total tank capacity of 1.5 gallons with a water level indicator
2. An energy efficiency ratio of 0.93, ensures that your money is well spent
3. Four different colour options.
4. The dimensions of Aprilaire 600 Humidifier are 15.6 x 15.6 x 12.7 inches
5. A silent, powerful unit that can easily be used in your home.
6. You will never have to worry about this unit over-humidifying or under-humidifying your home with its built-in hygrostat.

Pros & Cons

  • The tank has a cover with a view window, allowing you to see the water level.
  • An adjustable humidistat ranging from 75% to 100% humidity that can maintain humidity at the optimum level.
  • A filter that can be used with this unit to help keep the machine functioning efficiently by extending the life of its water tank.
  • The power cord is short and not easily replaceable.
  • It may be difficult for some to clean the filter because of its small size (5/8 inch).

Aprilaire 400 vs 600: Differences and Similarities

The Aprilaire 400 and Aprilaire 600 are both whole-home humidifiers, but what are the similarities and differences between the two models? Both the Aprilaire 400 and Aprilaire 600 are designed to humidify the air in a large area, and both do a great job of humidifying.

The Aprilaire 400 is made of steel and the Aprilaire 600 is made of plastic. The Aprilaire 400 and the Aprilaire 600 both have a water capacity of 2 gallons, but the Aprilaire 400 has a much larger fan capacity than the Aprilaire 600.  The Aprilaire 400 and Aprilaire 600 are designed to be used with Aprilaire whole-home humidifiers, and they are compatible with the Aprilaire 300 and 400. The Aprilaire 400 and Aprilaire 600 are both wall-mounted units,The Aprilaire 400 and 600 both are designed to humidify a room up to 4,000 square feet. The only difference is the amount of air they can move. The Aprilaire 400 can move 400 CFM of air while the Aprilaire 600 can move 600 CFM of air. Both models are equipped with the same features and are very easy to install.


Conclusion/Our Recommendation:

In conclusion, the Aprilaire 600 humidifier is a great unit that offers easy use without needing to be cleaned or replaced often. The machine can maintain as much as 30% higher humidity than recommended levels, and its energy efficiency ratio is 0.93. This unit is also available for easy use without needing a filter change every few months, with the filter lasting up to two years. So, it would be a wise choice to buy it. And enjoy the features it offers.

We hope you have enjoyed our Aprilaire 400 vs 600 comparison. We would love to hear what you think about this detailed comparison in the comments below. If you have any other questions about the Aprilaire 400 or 600, please contact us anytime. Thank you for reading, we are always excited to know your thoughts.


Question: Is it worth the price?

Answer: Yes, definitely. It will provide optimal humidity levels at a reasonable price.

Question: Will this work for those that have cats?

Answer: Yes, since cats do not have fur, they will be able to absorb the moisture more easily and remain fresher longer.

Question: Does this make a loud noise when running?

Answer: Because of its compact size, it is actually quite when running. If you were to shake it, you will hear a hiss from within. At medium and large humidities, it is reportedly silent.

Question: Will this unit be damaged easily?

Answer: No. It is constructed of high-quality materials and therefore should be treated carefully.

Question: In Aprilaire 400 vs 600 comparison, which one is best in a nutshell?

Answer: Aprilaire 600 humidifier

Answer: No. It is constructed of high-quality materials and therefore should be treated carefully.

Question: Does this unit come with filters?

Answer: Yes, it does come with a moist filter and a dry filter for the tank area. You must replace these at least every six months to replace the dirt and debris that can build up within the machine’s tank.

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