I have wanted a whole house humidifier forever but never got around to it. This winter has been especially dry so it was time.If you are installing this yourself, be prepared to do a lot of work. I am particularly handy so I had no problems.The biggest challenge in installing this thing is finding the right space to fit it. "18 (tall) x 16.5 (wide)" doesn't sound like much, but it is. You need a space on your supply that's not only that large, but should also be ABOVE your A/C coils. Locate and measure for the space before you purchase.As for the DIY handyman, you will need to do sheet metal work and accurately cutting a large square hole. In my case (see above.... findding space), I had to MOVE a 6" duct to a different location so the humidifier would fit.You will likely need to do electrical work, as you need an outlet near your furnace. I modified the power switch that was on my furnace; I removed the single-gang box that the switch was in and replaced it with a larger box and added the outlet there. If you're lucky enough to have spare power nearby, congrats!You will need to do some plumbing, as you need to supply the humidiffier with water (preferably hot). The unit DOES comme with one of those awful screw-on saddle valves that just drills into a pipe, but I'd recommend against that for many reasons. Those things are just... trouble. I found a good spot in a 1/2" copper pipe where I added a "tee", and then stubbed off of that and added a quality quarter turn 1/2-to-1/4 valve. From here i was just a simple matter to run 1/4 copper tubing to the humidifier.As for the hummidifier CONTROL, you have choices. The 720M comes with a manual hummidistat. That has to be wired between the hummidifier, your furnace, and a 24V transformer that is included. But you'll have to keep fiddling with the dial as the outside temperature changes. THe 720A (50 dollars more) comes with a fancier humidistat with a digital display, and a tempoerature probe you run to outdoors takes care of automatic adjustments. The final choice (what I did) was to use my smart thermostat.To wire a NEST to the hummidifier is fantastically easy. The humidifier has 2 wires. One wire runs to the "C" (common, or 24V) connection that's on your furnace control board. And the second wire runs from the humidifer to the "*" terminal on your nest thermostat. EASY.In my case, the dude who installed my new furnace a year ago ran thermostat wires--- but only enough for the need at the time. Phrased differently, I had to run NEW thermostat wire through the wall to use thermostat wire with more connections, so I could hook up the "*" connection. It is just as easy to hook up an ECOBEE thermostat, just google around you'll find how to do it.I am quite pleased with the unit. In my opinion, it's pretty quiet. Yes, I can hear it running when the heat kicks on, but that's because I'm sensitive to sounds and I notice that well, it sounds.... "different". The sound coming through my ducts is just a HAIR louder than before and perhaps pitched slightly higher. My wife can't tell the difference from before. One other review I saw here on amazon (720A) the guy said it sounded really loud and whistlled etc through gaps in the cover. I did not experience this.The numbers tell the story. My humidity the other day was in the low 20's. This morning it's been beween 35-40. I slept much better and didn't wake up choking like I often do in the winter (I live in Wisconsin).The included diretions for the MOUNTING of the unit are well done. The instructions for WIRING the unit are almost nonexistant. These units are of course really designed to be installed by HVAC professionals. So, if you do this yourself, you need to be prepared to do sheet metal work, electrical, plumbing, and low-voltage wiring. RESEARCH your furnace's connections. RESEARCH your thermostat and controlling a humidifier. (Go get a smart thermostat if you don't already have one).Lastly, I believe the water runoff amount I'm seeing to be reasonable. This model recycles water so the runoff compared to previous models (ie the 700) is far less.

installed about two weeks ago. workng well so far. easy to install. the vendor was very responsive to my request and sent a new transformer quickly. i got the manuel version, which is sufficient for me. i mounted the controller in a convenient location linking to the main unit with about 20 ft low voltage wire. i dont mind changing it as the weather changes. the only complaint i have is proably the unavoidable waste of water. there is a small stream of excess water flowing out of the unit when it's working. maybe i can lower the inflow if i fine tune the unit. the instructions didn't mention this step and i don't want to mess up the operation. so i didn't try to test how low i can reduce the input. but that's a price i pay for the convenience of not having to manully load evaporators.

The 720 model has several smart design choices that led me to purchase this model over the 700.1. First and foremost, the fan design is FAR superior. The 700 draws air from the room that the unit is installed in through the vent slats on the top and bottom of the cover. The 720 draws air from the inside of the HVAC register and recirculates it through the fan. Although this fan design makes the unit slightly bigger, it is a much better design, particularly for those who have to install this in an area where the ambient air is not something you want to circulate into your house.2. The water recirculation tech is smart and should just be standard on humidifiers. This unit has the same water-saving valve at the bottom as the 400 model, so it is generally more efficient.3. You will see some folks complain about the hydrocore filter in other online spaces. While I agree it adds to plastic waste, they don't really cost more than the wicks for the older models at this point. They are extremely easy to take out and replace, whereas the 700 requires taking apart and reassembling the wick casing. The videos I have seen of this process for the 700 also reveal that this casing builds up really bad scale over time, so replacing this annually in the 720 I think will also just improve overall maintenance of the unit. For me, this is a win.4. Very minor but the mounting bracket has been improved and no longer requires securing with rotating clips to secure it to the plenum. This small design change makes the unit easer to mount and is just really smart. A small change that makes a big difference.5. The unit is as quiet as it could be. As I understand it, there is a low fan mode, but I don't think it is necessary. My office is adjacent to the utility space and I don't notice any sound bleed at all. You can hear it through the return vent upstairs, but it is a fan, so that will happen.Some small gripes:1. The directions and design of the unit kind of require you to install the unit with the fan attached, which is heavy. They could have engineered this so that the mounting bracket and fan were completely independent to make installing, particularly seating it with screws and making sure it is level, would be much easier.2. The solenoid is mounted on the back side of the water recovery unit. The solenoid is the most common failure point for all humidifiers and mounting it there is probably going to require taking off that entire component to get to it. If they had simply mounted the solenoid in front of the reservoire, maintenance on it would be far easier.3. Do not buy the unit with the install kit. The things they include aren't good quality (for example they don't include a copper supply tube, which is what is called for in their own instructions) and it is cheaper to buy the parts. Just buy the parts on your own. What you'll need:- 18/2 solid copper HVAC/thermostat wire (10-15 ft),- Lever or screw wire nuts (WAGO 221-2401),- 1/2" ID Plastic/Vinyl drain tube,- eight #8 3/4" to 1" self-drilling Sheet Metal screws,- 1/4" OD copper tube for water applications (don't use refrigerant line. You want one that is NSF 61 certified, sometimes called "utility coil"),- foil tape or silicone caulk to seal the edge, and- PEX cutter + push-to-connect Tee stop value (e.g., SharkBite UR24985A) OR one of the tap valves if you have copper pipes and don't plan to have an HVAC specialist install this. If installing yourself, I recommend getting some step bits to drill the corners of the plenum hole (to reduce stress risers) and you will need snips or something to cut the steel. I used Dremel EZ406-02 cut-off wheels and it was exciting (with the sparks) but very precise. Use some protective eyewear and cutting oil if you go this route...SMART THERMOSTAT USERS:I got this unit because I wanted my smart thermostat to be able to independently regulate humidity in my home. The TLDR is that this will work with any Ecobee with an ACC+ and ACC- terminal on the mounting bracket. I got the 720m because I had high confidence that I had this figured out and it would work beforehand. Ironically, connecting this unit to a smart thermostat is WAY easier and simpler than using either their manual or automatic control units.I did have to upgrade from the Ecobee 3 lite to an Ecobee Premium because the former doesn't have ACC terminals. Check your power company for rebates. One of the frustrating things about both the smart thermostats and humidifier makers is that they both pretend the other doesn't exist and neither company provides support for how to wire these units together. After a lot of digging, I came to the simplest way to wire this up with the existing wiring in my home that requires no heavy electrical work. My existing wiring had an extra unused blue wire that my original programmable thermostat wasn't using. This wire is required for your smart thermostat to control the humidifier, so skip this if you don't have one and it would be difficult for you to run extra wires. With the Ecobee 3 Lite, I had repurposed this wire for a C (common) wire so I didn't have to use the PEK. When I decided to install the humidifier, I upgraded to the Premium and used the PEK instead, which requires only 4 wires to run the thermostat. Use the standard PEK wiring instructions and then plug the blue/extra wire in the ACC+ port on the Ecobee bracket. At the furnace controller hook 1 lead of some 18AWG HVAC wire to the blue/extra wire and the other lead to the C (common) port at the control panel (note this resulted in the AC, PEK, and humidifier all having a connection there). Then run that HVAC wire to the humidifier. It doesn't matter which lead connects to either wire on the solenoid. I secured those with inline lever connectors to make it easy. Everything is working great. You do not use the 24V transformer in this case because the Ecobee and HVAC control panel are already running at 24V.Note: The Ecobee wiring menu, you will see that it also registers a wire on the ACC- terminal even though there is nothing there. This is because the ACC- and ACC+ are connected by a switch and the Ecobee uses ACC- to turn the humidifier off when not in use. There are some other menus to go through to set the humidifier up properly but this review isn't a space to cover those.