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Internet #203479938

Model #HE240A

Store SKU #126729

1,500 - 3,000 sq. ft. Whole-House Flow-Through Bypass Air Humidifier

  • Replenishes moisture throughout the home for more comfort
  • Less maintenance and cleaning than portable units
  • Protects wood floors and furnishings from drying and cracking
  • See More Details

Frequently Bought Together


Product Overview

The Honeywell Home HE240 Flow-Through Bypass Whole House Humidifier works with your home's heating and cooling system to maintain a proper, comfortable humidity level throughout the home. Besides protecting your woodwork and furniture from drying and cracking. The humidifier can reduce the incidence of static electricity, promoting a safer home environment.
  • For typical homes (older than 20 yrs) up to 1,500 to (less than 20 yrs old) up 3,000 sq. ft.
  • Utilizes home's HVAC system for whole-home humidity distribution
  • Easy mounting on either warm air supply or return air duct of forced-air furnaces
  • Reduces static electricity
  • Saves money and energy because the improved humidity makes for a more comfortable home, the thermostat can be turned down a few degrees
  • Easy-to-use humidity control included
  • PerfectFlo water distribution tray optimizes efficiency and water usage
  • Click here to shop all Honeywell Home thermostats
  • Click here for more information on Electronic Recycling Programs

Info & Guides

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Maximum coverage area (sq. ft.)
Maximum Room Size (cu. ft.)
Product Depth (in.)
Product Height (in.)
Product Width (in.)


Air Treatment Product Type
Whole House Humidifier
Color Family
Control Type
Floor drain required
Humidifier Features
Automatic Moisture Control,Installation Kit Included
Humidifier style
Bypass flow-through
Humidifier Tank Capacity (Gallons)
Included Items
Installation Kit
Installation kit included
Number of Air Filters Included
Pack Size
Product Weight (lb.)
Room Size (sq. ft.)
Large (Greater than 1000 sq. ft.)
Voltage (volts)
Water Filter Replacement Model#

Warranty / Certifications

Certifications and Listings
No Certifications or Listings
Manufacturer Warranty
1 Year Limited Warranty

Questions & Answers


Will this work with a 11.5” / 11.5” hole in duct ?

Asked by Harry October 27, 2020

The Honeywell Home Bypass Air Humidifier requires a plenum duct opening of 9.132 in. x 8.437 in. (WxH) and a by-pass duct opening of 6 in. in diameter.

can I reverse the air flow connection to the duct from right to left

Asked by Mary May 14, 2019

Hi Mary, Yes, the Honeywell Flow-Through Bypass Humidifier does give you this option. -Joey

I install the HE280 and the water will not flow. I tested the voltage at the Humidifier and it g...

Asked by Lyle March 10, 2019

Hi Lyle! When testing this make sure the furnace is running as well, make a call for heat, if the you still don't heat the solenoid click, you may want to reach out to us for support at 1-800-468-1502. Hope this helps! -Joey

Will this humidifier work when heating with a heat pump?

Asked by Gunner March 2, 2019

Hello Gunner! Yes, the Flow-Through Bypass Humidifier will work when heating with a heat pump system. The humidifier uses the warm air supply duct for whole-home humidity distribution. Hope this helps! - Jerry

Do you have installers?

Asked by Janet February 23, 2019

Hello Janet, Yes, we do have installers. Please go to this link: https://www.honeywellhome.com/en/contact-a-pro and it will provide Honeywell licensed contractors. Once you select a category and put in your zip code, it will allow you to select an installer in your area. I hope this was helpful. -Chea

what are the external dimensions of the unit?

Asked by Ron November 16, 2018

The humidifier measures 15.75 inches in width, 9.47 inches in depth and 15.75 inches in height.

is the discharge side reversable

Asked by MD November 8, 2018

Hello MD! Thank you for reaching out to us. The Flow-Through Bypass Humidifier allows you to reassemble the side plate with the humidifier port, to customize the orientation for your specific install. We recommend selecting a location for the humidifier on the supply (warm air stream) duct. Return duct mounting is acceptable if there are space restrictions on the supply duct. Hope this helps! - Jerry

I have limited space. How big is the mounting area?

Asked by torquewrnc December 12, 2017

The actual duct opening required by the Honeywell HE240 is 9.28 inches wide by 9.43 inches high.

I have installed the he 280 humidifier and I cannot get the water to the filter , I can hear the ...

Asked by woody November 14, 2017

Your solenoid is not working properly. It's an excessively common issue with this brand of humidifier. You'll have to return it for a different one and keep trying until you find one that works which is what Honeywell had told me to do.

What setting do I have this on in the winter

Asked by Gayle November 10, 2017

Hi Gayle! To set your Honeywell Flow-Through Bypass Humidifier for winter operation please do the following: 1) Turn damper blade to "winter" position. 2) Plug the humidifier transformer back into wall outlet and turn water supply to the humidifier back on by turning the handle on the saddle valve to the left (counter clockwise) until there is resistance. 3) Turn the humidistat to its highest setting and set the thermostat to 10 °F (6 °C) above the room temperature. 4) Observe that water is flowing out of the drain hose. NOTE: The furnace blower must be running to activate the humidifier. 5) Reset the thermostat and humidistat to a comfortable setting for automatic operation. (35% relative humidity is recommended.) Choose the humidity control setting using the combination of relative humidity/ outdoor temperature setting scale on your humidity control dial. Match the dial setting to the outdoor temperature to optimize the humidity level while reducing the moisture condensation on your windows. When the outside temperature is -20 F (-29 C) use control setting 15; when the outside temperature is -10 F (-23 C) use control setting 20; when the outside temperature is 0 F (-18 C) use control setting 25; when the outside temperature is +10 F (-12 C) use control setting 30; when the outside temperature is +20 F (-7 C) use control setting 35; when the outside temperature is above 20 F (-7 C) use control setting 40. I hope this was helpful! Thank you.

1,500 - 3,000 sq. ft. Whole-House Flow-Through Bypass Air Humidifier - page 2

Customer Reviews

  • 2.7
    out of 46 reviews
  • 44% recommend this product
Filter by:
Showing 1-10 of 46 reviews
If Done Right
I recommend this unit as a diy only if you have experience or you have the time to research the correct install procedure. Do not use saddle valve instead purchase an actual water valve like i installed. Also use a starting collar on either return or supply as needed for your application. I bought a cheap humidity monitor and placed it on my return grill to get an accurate reading on where my humidistat is actually set to as it is difficult to get a constant cut in/out. If done right it works well.
by Justin
1 person found this helpful
purchased to replace a very old Aprilaire 550 unit. footprint...
purchased to replace a very old Aprilaire 550 unit. footprint is a match and i didnt have to cut a massive hole in my furnace, which was nice. just follow the directions for wiring, took less than four hours and only the one trip to the depot. so 100 percent success.
by js
Do not buy this humidifier. In fact, I wouldn't even buy any Honeywell products. Their customer...
Do not buy this humidifier. In fact, I wouldn't even buy any Honeywell products. Their customer service is atrocious. I purchased one, discovered parts were missing, returned it to the store to find all the others were missing parts but took one home anyway. I then ran around town buying replacement parts. Only when I set to work did I find that the missing parts were hidden within the humidifier itself; wish they would have mentioned that. So I cut a slew of holes in my ductwork, install this second one only to have the solenoid not function after four hours of work. I had to remove the entire thing and exchange it for another one at the store. After installing the third one, the solenoid did work but it would not stay open to let the water through. Honeywell agreed to pay for an HVAC contractor to come take a look. When the contractor arrived he first told me it should not be attached to the supply duct, which is where the directions tell you to install it. He then said the pressure switch (which is supposed to detect moving air then activate the solenoid allowing water to move through) would never work in any scenario. He said the bypass system is poorly designed and in fact, the whole system is poorly designed. Great. He ended up having to rewire the pressure switch to bypass it and wire the humidifier to the furnace. The more I studied the humidifier while the guy was there, the more I realized how poorly designed it is, how it would never work properly and do the job it's intended to do. But does it work? Does it provide humidity? Nope, not really. In fact, it has made no difference at all. Not satisfied, I contacted Honeywell again who gave me the run around for two more weeks before I finally spoke to someone who essentially blamed me for being smart enough to install one but too dumb to find all the information I needed. He said this humidifier is only expected to create 20-28% humidity at best. Why bother? That's what my house is at anyway. I asked him where that information was as I would have liked to have known that beforehand; he stated we don't like to flood customers with too much information or they won't buy the product and take the risk. He blamed me, blamed the store employees, the weather, my furnace might not be the right type, every other variable in the book except his own product. Easy excuse for them -- it's everything else but our product. In the end, the only way to resolve this is either keep the thing, let it drain out and waste a ton of water and do nothing or return it and turn my ductwork into the Bride of Frankenstein by patching a million holes with bits of sheet metal. Did he offer anything? Nope, just a lame apology.
by bexster
Response from Honeywell SupportJan 25, 2017
Hi Becky, We appreciate you sharing your experience with the Honeywell Flow-Through Bypass Humidifier. We’ve been speaking with you via Twitter and we believe we’ve resolved this for you. Feel free to reach out to us again if you need any further assistance. Thank you! Honeywell
2 people found this helpful
Great humidifier, good value - preparation & patience are key
So far I'm really pleased with the very noticeable over-night increase in humidity ~20% --> ~40%+. I decided to go with this model based on size,price, & features. Install overall took me about 6 hours. Most of that time was watching videos, reviewing instructions & planning! Remember (Measure x 3) = (Cut 1). Get familiar with tin snips! Wiring was easier since I could tap 24V side of furnace control board (R + C) - didn't need to run another 120V line nor use the included trans. Adjust water valve down to minimize excess. I added a 5-year ice-maker type filter on to mitigate sediment build-up. Seal her up good & get ready to breathe easy!!
by DWigs
25 people found this helpful
Rating provided by a verified purchaser...
Rating provided by a verified purchaser
by HomeDepotCustomer
by HomeDepotCustomer
Works like it's supposed to
Humidifier works great, I've had no issues. Installation was easy although time consuming mostly due to furnace location. It is recommended to install the unit on the supply side but I had to install on return side again due Honeywell's site to determine which pad assembly is required. The reason I didn't rate it a 5 is the instructions are for two models, HE240 and HE280 and the unit doesn't say which model I got. The replacement pads are different for each model.
by cnoel
It seemed like a good idea when it was installed on my new furnace. Two months of use and then heard the sound water gushing in my basement where my furnace is located. Water is gushing through the drain hose and overflowing on the floor. Not a good quality product. Contractor didn't think flow control was a feature of the humidifier. I had to reduce the water flow manually to a trickle. I now realize that I had a crappy contractor and a crappy product. Double whammy!!!! I do not know any better so I will just get a new one installed and get another 30ft. guarantee.
by Mr. Dryhouse
This is a smaller version of the Honeywell unit on our main-floor furnace, but it is still pretty...
This is a smaller version of the Honeywell unit on our main-floor furnace, but it is still pretty big. It was difficult to find clearance for the pressure switch because of tight clearances. I also learned that not only must it be installed carefully to be level (left to right) but also vertically (front to back) so as to avoid drips. Once installed, it is working quite well. Remember to replace the evaporator pad every fall!
by John
Solenoid will fail, can't replace the part
Once the warranty is up the Solenoid will fail and cause the water to constantly run. Good luck finding a replacement solenoid, you'll have to replace the entire unit.
by waterlogged
Showing 1-10 of 46 reviews