AprilAire 400 17-gal Whole-House Evaporative Humidifier with Automatic Digital Control for up to 5 000 sq ft AprilAire

Let me start off by saying I installed this myself, and I am a technician by profession, so it may have been easier for me than for some people. It did not seem very complicated to me though, and the directions included appear very clear and straightforward. I think anyone with some basic tools and mechanically inclined could do this themselves, otherwise you might want to hire a professional installer. The kit included everything I needed except sheet metal screws and tubing (1/4" copper for water supply, 1/2 clear vinyl for drain), and some additional 14-20 AWG wire nuts. I also bought an additional T-fitting with 1/4 turn shut off valve to hook up the water supply in my 1/2" copper hot water pipe. I don't recommend using the saddle valve they provide in the kit for the piping, as they frequently fail, and do not meet code. I mounted the unit on the return manifold, and used a couple of 90° 6" elbows and a few feet of flexible HVAC hose for the bypass duct, and sealed it all with the silver foil HVAC tape. As for the functionality of the unit, it's working great so far. I really like the water saving feature on it. It comes with a composite material filter (paper/metal screen) and a tray with float sensors to shut off the water valve if it gets full. This makes for a much more economical use of water in my opinion, and still has an overflow drain tube in case of malfunction. I like the outdoor temperature sensor to use the automatic feature for humidity adjustment, and it also has a feature to turn on the furnace blower to circulate and humidify the air if the humidity level is too low, separate from the thermostat control, which is very nice. Both features work perfectly so far, and my relative humidity went up 10% after the first day. This is the most precise and full control featured humidifier I saw at this price point, and was a very good value for the money. Read more

I installed this last week in the eastern US with currently well below freezing lows. It added about 5-10% humidity, which is just what I wanted. My water is soft, so hopefully no issues with dissolved salts. The included 6” duct is too short. I built a bypass using some elbows and a straight 2’ section of 6” duct from a home improvement store. I’m using a c-wire substitute for my smart thermostat. Everything works except the fan only mode. That stopped working when I installed this. Read more

The '2' rating for 'Easy to install' lies inherent in the general knowledge needed, executing a number of trade-tasks: Electric, plumbing, HVAC It's a well made humidifier, nicely packaged, relatively easy to understand install instructions for the handyman type. Several great customization features that work very well with my furnace. The digital controller is intuitive, allowing me to modify features 'at will' quickly. Installing the humidifier 'level' is very important. Note: Check for 'plumb' on the metal venting you are mounting the humidifier to or you may have issues later, depending on the model you purchased. This review is for the 400 series. Read more

I bought this humidifier because I loved the idea of the unit not running water constantly while on and draining out the bottom constantly (like most other units do). This unit seems to be much more efficient, as it fills the bottom reservoir until full and shuts off, allowing the filter to slowly wick up the water. The install was pretty straight forward until it came to leveling the plastic housing of the unit. Left-to-right leveling was as easy as setting a level on the top of the unit while drilling in the self-tapping screws. But back-to-front leveling became an absolute nightmare. The old humidifier I was replacing was mounted on the side of the ducting that had the "X" pressed into it for structural support. This equated to not having a level area to mount the unit too, but I didn't want to cut into the ducting at a different location. There really isn't a good spot to check front-to-back level on the unit. the internal plastic frame flairs out around the entire hole. The bottom ledge also flairs out. It came down to me having to pop the top off of the filter framework and pull the filter pad out. I then put the top back on and the filter framework back in (without filter pad) and was able to level off the bottom two lips of that. This actually seems to make a lot of sense, because this filter housing is the most important part to be level, as it has the water running down it. The plastic framework of the actual humidifier is secondary. I ended up having to add some adjustable braces to the inside of my ductwork to push the top of the ductwork out and the bottom in. Try to mount to the flatter side of the ducting. The only other issue I had was that the humidifier requires a different control unit if you want to wire it in manual mode. The instructions don't do a good job of showing that. I wanted to run the unit in manual mode until I ran the outdoor temperature probe. and the wiring diagram made that look as easy as two wires (like the old unit), but the manual mode still required about 6 of the 8 wires connected. All and all, I think I will love the unit now that I seem to have the kinks of my specific setup worked out. 3 Read more