Aprilaire Steam Humidifier 800 with Automatic Digital Control

The Aprilaire 800 Steam Humidifier with Automatic Digital Control humidifies spaces up to 6,200 square feet. Great for large homes or spaces without a centralized heating system, this will be sure to meet your humidity needs!

The Aprilaire 800 Steam Humidifier is a whole home humidification solution that helps homeowners reach their optimal indoor comfort. This Aprilaire 800 humidifier covers up to 6,200 square feet and can produce up to 34.6 gallons of water per day!


This Aprilaire 800 model is 100% automatic, so there is no need to manually dictate the humidity settings. However, if you do prefer manual control to automatic it can be installed in manual mode. The Aprilaire 800 is designed for a remote or duct mount with no additional accessories needed.


Typically, this unit is purchased for large homes or applications where the installation of evaporative units is less practical. The 800 Steam Unit can accommodate crawl spaces, attics, and non-forced air heated home.  

The Aprilaire 800 unit delivers the humidity into your heating and cooling ducts through a dispersion tube which connects directly to our home's airflow.

*Note: If you do not have a centralized, forced air system in your home, you will need to purchase the Aprilaire 865 Ductless Steam Humidifier, which includes the humidifier and the Aprilaire Fan Pack to provide humidification to your home without the need of ductwork. Click here for the Aprilaire 865.

The Aprilaire 800 uses the latest absorption and dispersion steam technology to adequately disperse steam to your airflow without causing any condensation problems within your ducts. Once the water is boiled and steam is produced, it uses the new technology to disperse the steam into the air through the dispersion tube mounted on your HVAC system's ductwork. The openings within the dispersion tube are fitted with "tubelets" which are designed to steam over a wide area in the duct and direct any condensed moisture back into the steam hose, keeping it out of your HVAC system.  


Maintenance: The Aprilaire 800 humidifier's maintenance is very simple and only takes one step! Under normal conditions, you will need to replace the Aprilaire 80 Canister annually. The unit will automatically notify you when the canister needs to be replaced. The manufacturer also recommended inspecting/cleaning the unit every 500 hours of use.   


Benefits of Steam Humidification:

  • Prevents Flu and Allergies
  • Neutralizes Static Electricity
  • Reduces Pet Dander and Discomfort
  • Protects Fine Furniture, Wood Floors, and Musical Instruments
  • Relieves Dry Skin and Scratchy Throats
  • Reduces Heating Costs 


The Aprilaire 800 steam humidifier comes with an Aprilaire62 automatic humidistat which includes a built in blower activation switch and an outdoor sensor. The Aprilaire62 humidistat will mount directly to your heating and cooling system to accurately detect and deliver the appropriate amount of humidity to your home. This humidistat is so advanced it will automatically adjust the humidity delivered to your home based on the outdoor temperature changes. This takes all of the guess work out of humidity settings, make your life a whole lot easier! 


The Aprilaire62 automatic humidistat is equipped with notification lights to quickly alert the homeowner if the system is in need of maintenance.

Red =  The humidifier is not working and needs your attention.

Green = The humidifier is working properly.  


The Aprilaire 800 Humidifier is Shipped to you as a Complete System that Includes: 

1 Aprilaire 800 Steam Humidifier 

Model 62 Digital Automatic Humidistat (includes an outdoor temperature sensor) 

Dispersion Tubing Steam Hose (6 feet) 7/8"

Drain Tubing (10 feet) Hose Clamps

1 Self-Piercing Saddle Valve 

Mounting Screws  


This Aprilaire 800 humidifier requires a plenum opening of 1-1/4" Diameter Hole.  For electrical reference, this unit can operate on 120, 208 or 240 Volts with an 11.5 - 16 AMP requirement. (depending on how many gallons per day you need produced). 




How To Change The Steam Canister
Aprilaire 800 Steam Humidifier Overview
Aprilaire 800 Steam Humidifier Maintenance


If you have any questions regarding this product, please use the HVAC.com Contractor Directory to connect with a trusted contractor in your area.

  • Brand: Aprilaire
  • Genuine OEM Product: Yes
  • Control Type: Automatic Digital
  • Coverage: Up to 6,200 sq. ft.
  • Steam Rate: Up to 34.6 Gallons/Day
  • Electrical: 120 & 208 & 240 Volts
  • Product Size: 10-1/8"W x 7-1/8"D x 20-7/8"H
  • Weight: 27 lbs.
  • UL Listed: Yes
  • Manufacturer's Warranty: 5 Years*

    *Click here to see the manufacturer's warranty
    Reviews Write a Review
    • TomC

      I bought and installed this humidifier a few weeks ago, and, boy does it work! I have a 4900 sq ft. house and have tried the less-expensive, simple, non-powered by-pass humidifiers in the past, with negligible effect. I wanted something that was going to actually keep a comfortable humidity level during the dry Colorado winters. After getting a new furnace, I spoke with my contractor who, personally didn't think humidity, or lack thereof, was a big deal, but did recommend this unit as the right product for the size of my house and my personal humidity preferences. I chose to install it myself as the cost of having my contractor install it, I thought, was too high. Plus, I like knowing how things work and it gives me a sense of "connection" to my house to help troubleshoot when I hear things go bump in the night. The instruction manual had adequate detail to it, but I found other videos on youtube helpful as a general guidance before really diving in. I chose to wire the humidifier for its maximum potential by putting it on its own 20 amp circuit and wiring it for 250 volts. I have it setup at the 16amp dip switch setting and left the jumpers at the default of 250 volt setting. After reading through the humidifier instruction manual, though, I couldn't see how the humidifier would turn on/off with the furnace. *That* information was found in the separate humidistat installation manual. It was quite clear and straight-forward how to hook up the humidistat to the furnace control board. This unit had everything needed (i.e., humidifier + humidistat), except for the wiring needed to connect the humidistat to the humidifier (2-wire, 18ga) and the humidistat to the furnace (5-wire, 18ga). Well, and the wiring needed for running the outdoor temperature sensor to the outside of the house. For now I have the humidistat in "manual" mode, which doesn't make use of the outdoor temperature sensor to automatically adjust the humidity levels based on outdoor temperature. I'm doing this for now just to get a feel for how well this unit can humidify at a maximum. So far I'm able to get the humidity levels up in the 50% range. I do think that's too high as on cold days the windows start to sweat with condensation. I'll try out the automatic setting with the outdoor temperature sensor soon, though. One thing I'll mention is that I notice the "boiling" sound of the water echoing through the vents (even on the top floor, with the furnace waay down in the basement) when the unit first turns on when the furnace flames fire up and before the blower starts. Once the blower starts, though, you don't hear the boiling. If I hadn't installed this unit myself and understood how it works, I'd probably start to question the contractor's installation quality. Again, that brings me back to the concept of being "connected" to your house and knowing which sounds come from where and whether they're normal, good, or bad. Starting in October in Colorado the air humidity drops, especially with the use of a forced-air furnace. I find my skin drying out very quickly. In the last few weeks with this new humidifier, my skin has been back to normal "Summer" mode. No cracking and itching! I can't recommend this humidifier enough! Additionally, I found that HVAC.com had the best price!

    • turk

      I was not sure if I could handle the install myself, not having done any plumbing work and pulled a new circuit from a power panel but I think I did a fine job with great attention to detail and much over engineering, as in 30 amp, 240V dedicated circuit! :-) Feeding it well water with a sediment filter in the line. The canister looks nasty and I already had to clean it after about a month use but the house that used to be in single-digit humidity now cruises at ~40. If I had a contractor install it, the system would be a black box to me; and I would have less money in the bank. In Northern VA they quoted close to $3K to install this unit (including the unit).

    • libchiak

      I bought this steam humidifier a few weeks ago. It was a fun project. I had to install a separate electrical circuit providing 240V and the water connection. Everything was relatively easy to install. The humidistat was easy to connect to my furnace system. The details in the manual very easy to follow and I had no problems at all. Before the humidifier was installed my RH was about 20%. We were using a small portable one which helped a bit in the location it was. But now after the humidifier was installed we didn't go below 30%. It really depends on the outdoor temperature and since it is around 34 degrees right now the humidity is between 40 & 45%. I am not sure why it is so expensive, but it works well. i had to buy an extra material for the electrical and plumbing so i think i spent about over $100 for that. (breaker, cable, switch, pipes, valves, insulation, thermostat cable and for the cable for the outdoor temperature sensor.) My configuration is fully automatic now since I connected it to the outdoor sensor and the HVAC blower is in the ON mode. It really makes a big difference. I love the product.

    • emplk

      This humidifier allows you to very finely control the humidity level. Much more precise than a bypass type-especially with a larger. Installed this about a month ago by myself, with help and tools from my dad. (I'm not a HVAC person but can follow a manual and relatively handy). Aprilaire tech support line was amazingly helpful in clarifying a few installation questions both before and during the install process. Most def recommend running a 240v electric line in order to get the max benefit of steam generation. Temp now outside is about 25 degrees and indoor humidity is hovering around 43%-perfect!

    • sreddy

      I would say this humidifier is the best in its class. The humidifier works well and keeps my home dry-free now. Good part is it has both auto and manual modes. Only thing i didn't like was about the installation (only reason to cut down one star). The instructions were not step by step In Detail. Only the experts can understand not the average consumer. But if you put a bit effort and time, it is easy then. I installed it myself which took almost a day as i had to run to the home depot for few tools and accessories that they do not supply. But once you install it, you feel yourself that it is so simple. Very good product.

    • bb18

      Moved to Virginia, in a new home, asked a few HVAC technicians to quote installing a steam humidifier unit. Both quotes were in excess of $3300. So I did some searching, and found this unit on HVAC.com. I would recommend this over the Honeywell unit especially after the install. All that was needed was 2 small holes in my ductwork. 1 on output for the steam tube and 1 on return for the humidistat reading (my return was a cylinder shape and still had no problem mounting humidistat control). Some learnings of myself as a modest do-it-yourselfer: I paid someone to run a new 240 line from my breaker box to my HVAC room. Got a hold of an electrician on their off hours to run line and cut holes in dry wall replace blanks for $250. Also I have a CPVC pipe for my water line instead of copper so I did not feel comfortable using the saddle valve for water-worried it would crack the line. I used the shark bite system - so I did not have to use pipe cement and don't need to dry the pipe. Highly suggest going to Home Depot/lowes to get system. I had 3/4" main - used a T reduction to 1/2" and got a short 1/2" CPVC to a ball valve reduction to 1/4" then used refrigerator 1/4" Line to humidifier you will also need 2 lengths of thermostat wire. 18/8 from humidistat to HVAC system (2 wires into HVAC system to wire to spare lines going to outside to condensing unit so don't need to run line for thermometer resistor ) and you only need 18/2 from steam unit to humidistat control (I used 2 wires from the extra 18/8) Very easy to install - just pay attention to wiring diagram.

    • Aldhaif

      This humidifier arrived as promised . It comes with the outdoor sensor which is great so you can set it on auto . It will works better with 240V

    • JimJr15

      I initially bought one of these units to try it our on one of my two heating units. I was so satisfied, I bought two more. One unit for my other heating system and one for my parents house. Our house used to go as low as 19-20% humidity during extended heating cycles, now it's a comfortable 35%, automatically adjusted for outside air temp by the automatic humidity controller included with the Aprilaire 800 unit. I installed them myself and I am very happy with these units. Shipping through HVAC.com was very quick on all 3 units

    • SSS Tom

      After much research, I decided to purchase the Aprilaire 800 Steam Humidifier, and it was definitely the right choice! His compact unit packs a big humidifying punch, and maintains the humidity in my 2,000 square-foot house at around 41% RH. I did not have a 240v circuit nearby, so the unit is running on 120v, which seems to be fine for my application. If you have a larger house, I recommend running the humidifier on 240v. I should note that the inlet valve to the unit leaked upon initial installation. One call to HVAC.com customer service quickly remedied that problem. The very friendly customer service agent had a new valve drop-shipped from the manufacturer, and it arrived via FedEx within three business days. I'm very happy wit the Aprilaire 800 and with HVAC.com, and I will certainly order from HVAC.com in the future.

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    Aprilaire Steam Humidifier 800 with Automatic Digital Control