Holmes HAP9424B-NU Air Purifier: Trusted Review & Specs

Some HEPA-type air purifiers are better than others. The Holmes HAP9424B-NU is the newest upgrade from the previous tower Holmes HAP412N-U and Holmes HAP9422-NUA with enhanced power to use. We are happy to write the Holmes HAP9424B-NU Review to help you identify your future air purifier.

The air purifier seems to be discontinued, so we recommend you to check the review of Holmes HAP8650B instead.

Holmes HAP9424B-NU ranks D+ in our air purifier ranking list. We give the biggest and most thorough database of air purifier reviews in the world.

UPDATE: As the Holmes HAP9424B-NU appears to be fully sold out, I recommend properly checking our deal before reading this review, as the review itself is pretty lengthy.

In Breathe Quality, we have reviewed all air purifiers under these sections. Also, we guarantee that:

  • We do give honest reviews (both pros and cons) so anyone will guarantee to have the wisest choices.
  • We do not (and never) exaggerate one product just to let you click the links and buy that product blindly.


holmes hap9424b-nu review

  • Better performance than predecessors
  • Good customer service

  • No True HEPA filter
  • Low performance
  • Discontinued

Holmes has been in the world of air purifier of the United States for more than 35 years, under the name of The Holmes Group. Now, being acquired by the Jarden Corporation, this brand has a chance to improve their air purifiers to a next level. Our today review unit is the Holmes HAP9424B-NU Review.

Other Holmes’s Air Purifier Reviews:

Holmes HAP9424B-NU Price

The Holmes HAP9424B-NU is currently unavailable from The Holmes Group’s website. It is hard to find a deal anywhere online, but in Breathe Quality, if you still like this air purifier, you get our promise for an available deal.

For the price, the Holmes HAP9424B-NU is a bit pricier than the old Holmes HAP9422-NUA, launched at $85. For an air purifier with only inferior HEPA-type air filter built-in, we will prefer the Holmes HAP424-NU or Holmes HAP242-NUC instead. By the very nature of a more expensive air purifier, Holmes HAP9424B-NU is capable of dealing with the very small impurities, but that’s not enough to keep the value of a real True HEPA air purifier.

Like I said earlier, this is the reign of the things like GermGuardian AC4825 and GermGuardian AC5000, which has the real True HEPA filter to deal with the airborne particles as small as 0.3 microns in size. Or else, you can search for the Levoit Vista 200, AeraMax 100 or Whirlpool WPT60, as they are all under the range of $80 to $100, with the tower design and great, modern features to use.

Top Holmes HAP9424B-NU deals right now

Holmes HAP9424B-NU HEPA-type tower air purifier.

Powerful HEPA filter with baking soda applied. Great for medium rooms.

Related post: Best air purifier 2023.

Holmes HAP9424B-NU Design and Size

The Holmes HAP9424B-NU is overall much likely the same as the previous Holmes HAP9422-NUA, with strong base and bullet-shape appearance. This air purifier still has two concave holes on top, but they are way more stylish than the older brother.

It keeps the original dimensions from the original design, and its height is 28 inches, which is similar to the GermGuardian big tower air purifiers. The only difference is the coat of total black from our today unit, as well as the perforated holes from the air vent. Holmes HAP9424B-NU uses the traditional back-to-front air flow system concept to clean the air inside your room.

There is still one manual switch to change the fan speed.

Holmes HAP9424B-NU weighs 11 lbs, and you can easily move it around your home with the built-in handle.

Related post: Best air purifiers for bedroom.

Holmes HAP9424B-NU Filters

To decide the performance of one air purifier, you will need to know about the quantity and quality of its air filters, as well as the air filter types are used. The Holmes HAP9424B-NU has the 2-stage air cleaning system as below.

  1. HEPA-type filter – It is not a True HEPA filter, and the quality is much inferior. But the air filter from Holmes HAP9424B-NU is said to clean 99% of any particles down to 2 microns in size.
  2. Ionizer – The technology of ionizing air purification from Holmes, which complies the standard safety of CARB completely.

As you can see from the chart below, the actual performance of this Holmes HAP9424B-NU is still far from the threshold of 99% efficiency like advertisement. Notice that the HEPA-type air filter is inferior, which is not tested or certified anywhere to meet the standard of a HEPA. It is not just in the case of our today unit, it happened in the Holmes HAP9240-NWU and Holmes HAP242-NUC, too.

Holmes HAP9424B-NU review

The HEPA-type filter of this air purifier needs to be replaced after 6 months, with a cost from $12 – $17. At the moment, you can buy the True HEPA filter for the Holmes HAP9424B-NU, with the cost of $44. However, at the time of writing, there is a great sales for the Holmes True HEPA air filter, and you can grab it below. With the True HEPA filter, the efficiency of Holmes HAP9424B-NU increased from 90% to exactly 99%, which is nearly 10% in difference.

Related post: Best air purifiers for allergies.

Holmes HAP9424B-NU Room Coverage

The Holmes HAP9424B-NU is a tower air purifier for medium rooms, and I suggest to use it in a room of 195 square feet.

The ACH of Holmes HAP9424B-NU is 4X. This air purifier can clean your room in every 15 minutes.

The CADR of Holmes HAP9424B-NU is 126 cfm in general. It is 20% better fan power than the previous Holmes HAP9422-NUA.

Related post: Best large room air purifiers.

Holmes HAP9424B-NU Sound

The Holmes HAP9424B-NU has the noise level of about 55 decibels (db) at the highest setting. You can even hear the crackling noise from the ions inside this device, and some people even complained that the lowest speed is too loud to sleep to. I guess The Holmes Group pushed it too far for the inconvenient sound, and it is really, really disturbing to use.

But, just like other Holmes air purifiers, the Holmes HAP9424B-NU is clearly not good enough to use in the quiet places.

Related post: Best air purifiers for baby.

Holmes HAP9424B-NU Power Consumption

One of our most FAQs is “Do air purifiers use a lot of energy?” In fact, air purifier must be used for a long time to be efficient. And power consumption is one important criteria to review how much energy this air purifier will consume.

The power consumption of this Holmes HAP9424B-NU is 110 watts, which is rated 1/5 in many negative Amazon reviews. And I must be honest, it is too high for an air purifier without True HEPA filter, or superior fan power.

For running the Holmes HAP9424B-NU 8 hours per day, you need to pay $35 each year.

Related post: Best air purifiers for pets.

Holmes HAP9424B-NU Additional Features

Like what I reviewed in the review of Holmes HAP9422-NUA, the Holmes HAP9424B-NU has exactly the same set of additional features. Which is, sadly, nothing, except for one indicator for filter replacement. Well, I guess you don’t have to explore any more from this air purifier.

Related posts:

1, Best air purifiers for smoke.

2, Best air purifiers for dust.

3, Best air purifiers for mold.

Holmes HAP9424B-NU Customer Service

Even being acquired for more than 10 years, the Holmes products are still one of the most popular electric appliances today. Then the reason can only be their impressive customer service. If you need to contact them, you can easily do so by filling in the information at their Contact page, or calling them via phone at 800-546-5637.

Once you make an order, you will get your Holmes air purifier with a promotion of Free Shipping over $50. However, the promotion is only applied at the time of writing, so if you can’t find the Free Shipping option, you should choose to buy from Amazon. The most wonderful thing is, after your purchase, or any reason you are not completely satisfied with the Holmes air purifier, you can return your item within 30 days of receipt for an exchange or refund of the purchase price. Great, isn’t it?

And don’t worry about your air purifier, it will be backed up by a great 5-year warranty from The Holmes Group. This is also the best warranty for an air purifier brand that only targets low-range segment.

Top Holmes HAP9424B-NU deals right now

Holmes HAP9424B-NU HEPA-type tower air purifier.

Powerful HEPA filter with baking soda applied. Great for medium rooms.

Our verdict

This could be the end of a product line, and just making the optional True HEPA filter doesn’t make the Holmes HAP9424B-NU a better option to pick up at the moment. Also, it is discontinued.

Holmes HAP9424B-NU Air Purifier: Trusted Review in 2024
Holmes HAP9424B-NU Air Purifier: Trusted Review & Specs

Holmes HAP9424B-NU Reviews and Specs (Air Purifier Trusted Reviews in 2024). ✓ Cleaning Power: HEPA-type filter ✓ Value: 2.4/5 ✓ Certified Review

Product Brand: Holmes

Product Currency: USD

Product Price: 85

Product In-Stock: SoldOut

Editor's Rating:
  • Performance
  • Features
  • Annual Cost
  • Design
  • Price


This is not an air purifier to pick any more.