My old 1997 Aprilaire 760 had the 24 volt transformer already installed within the cover near the motor.The 700 M need a 24 volt transformer (included separetely in the box) and has to be installed outside the 760 M between the thermostat and the Aprilaire 700 M as showed in the installation instructions.

Fairly easy to install. I hooked the thermostat to the air intake supply side( pictured on the left) and I hook the humidifier on the side of the duct coming out of the furnace. I set it at 40% and as you can see from my nest thermostat and my smart sensor it is working perfectly. The air in my house feels much better. My skin is not so dry and my kids haven’t been getting bloody noses anymore . Previously my air was 20-30% humidity in the dry winters in Utah. I hooked the water line directly to hot water line off my water heater and I believe that is key to get the humidifier to work correctly. Total install time was only a few hours.

I considered installing this myself, but I went with a recommended technician instead - luckily. Why time I use enercare it's horrible, so this time I went with the little guy. This humidifier didn't come with any tubing, not even the feed line from the supplied water valve to the humidifier. Didn't come with the inserts for fastening the line either. The tech said he'd never seen a humidifier sold without these required parts, but he carried extra because they often need replacing. So big issue averted, otherwise I'm sure I would have had to pay him to get the parts and come back. Contacted Amazon to refund the cost of the missing parts, they said go screw. Not impressed. Buyer beware, other than cutting into the ducting neatly and accurately, it's not super hard - but if you don't have the missing parts.. you're going to have to go get them. Feed line tube, feed line end metal inserts, drain tube and control box wire were missing and all 100% required. Amazon said I could return it for a refund rather than reimburse the missing parts. Because who would take the parts of and leave big holes in their ducting while jumping through hoops. It wasn't even much cheaper than the tech would have charged for it, at the time, now the Amazon price is higher.

Product arrived. Installed it in 4 hrs next day. It brought the humidity up in our 2200 sq ft home in approximately 4hrs. I would recommend this product.

Works fast for bringing up humidity in a 2100 square ft home. Used hot water at 110 F . Installed on return air plenum because no room on supply side. Was a lot of work to get it all done properly. Took my time. Use an Ecobee 5 to control it. Very happy with the final install.

Easy install once I had read the instructions closely. Hooked it to the hot water line in a 1200 sq. ft. home. It works beautifully, exceeds my expectations. The air quality is awesome.

OK, this is exact same as the automatic except it has the manual humidistat.I was a bit nervous about installing this because of how little room to install this. There is literally 1/2" between the wall and this now. But works amazing!Straight forward installation. Installed on the supply plenum. One thing, don't use the saddlevalve they give you. Go buy a sharkbite valve. Super easy to install with no soldering required.List of supplies used.1. Metal tape (duct tape for the plenum but made of metal)2. Tin snipe. (To cut the plenum)3. 3/4" sheet metal drill bit (titanium or better)4. Sharkbite valve (connect to water line. Just push pipe in both sides((1/2" osd))5. Sharkbite 1/2" to 1/4" on/off valve6. 1/4" osd foggy plastic hose (connects to the water inlet on humidifier)7. 1/2" clear tube (for the drainage tube on humidifier to drai )8. 18x2 thermostat wire, wire nuts, and plastic tube to hide wires.9. 1/2" copper tube. Maybe need only 3"-5" (extends the sharkbite valve)10. 20' outdoor extension drop cord (only if you don't have plug near supply plenum)11. Level12. Electric drill13. Yellow handle tin snips (yellow means cuts strait lines or curved)14. #8 self tapping sheet metal screws. 1", and only 4-6 is needed.15. Pipe cutter16. 13mm open socket wrenchShut off breaker to furnace. Do not install before you do this.So, the toughest part on the install was cutting the plenum. I didn't have enough room for the drill to drill hole, but was creative and got one made. The instructions are the template for the humidifier base. Used a level and made sure it was on level. I chose to use the supply plenum to install so I wouldn't need to use hot water. Save a few gallons of water daily. After the square hole was cut, I used a hammer and pliers to make sure the edges were even. Then mounted the base, and screwed it in. Next, used the metal duct tape (do not use regular tape, must be the metal kind) to tape around the base. Take your time and make it look good.Next, wiring. The bottom of the base has two brown wires. Using the 18x2 thermostat wires, connect one brown wire to the common circuit on the furnace circuit. Should be labeled C. Next, connect the other wire to the W (24v aux). Connect that wire to one terminal on the humidistat. First mount the humidistat where you want it. After the the power wire is connected to the humidistat, add another wire to the other post in the humidistat. Doesn't matter which one you use. Take that wire and connect it to the other brown wire on the base of the humidifier.Next is the water. If you have a water softener, you will be using the copper line going from there to the water heater. Shut off the main valve and grab a small bucket (water will drain from the line) and place under where you want to install the sharkbite adaptor. Use a black marker and mark the pipe. Then measure 1" both left and right. This is where you want to make your cut. Cut the pipe in both spots so you have a 2" space between ends. Slide the sharkbite adaptor in between and press the adaptor hard in each side. It will lock in to place. Cut a 3"-5" piece of spare copper pipe and push in the middle of the adaptor. Then attach the 1/2" to 1/4" sharkbite valve. Push it hard and it snaps in. Take off the 1/4" but and the copper coupling inside. Slide the foggy 1/4" tube through the but and then the coupling and in to the valve. Using a #13 wrench, tighten the but down as much as you can without breaking it. Connect the other side of the tube to the bottom of the humidifier base. Using the same method of through the but and coupling, then tighten down a lot. Otherwise this will leak. Next connect the 1/2" drain line. Run it from the bottom of the humidifier base to your drain near the water heater or softener. If there isn't one, you will need to buy a pump and attach it to there and pump it out of the house or to a drain.Last, use the extension cord, connect from outlet to plug on the humidifier. Use the black tube to conseal the wires if you want. Turn on the water to make sure no leaks. If there are some at the valve and base of humidifier, tighten those nuts down. It will stop leaking. May seem like you will break the sylanoid on the base, but it won't.Turn on the furnace breaker, set the heat to high to you can monitor the humidifier. It should be working fine.Alternative install. Use the transformer and connect to the HUM spot on the circuit board and the other to Neutral, the the humidistat to one of the back side and other goes direct to the brown wire on the base of humidifier.I am not a HVAC tech. So if you have questions I can't really help. But installing yourself will take 3-5 hours depending on trips to the hardware store. It will also save you between $350-$500. The total cost of the parts were right around $100. But because I didn't have the drill bit, the pipe cutter, yellow tin snips, metal tape, extension cord, or tubing. If you have those, the sharkbite adaptors will be around $25.So far we have felt an immediate impact on the air quality. Well worth the price.

The Aprilaire arrived quickly within 3 days. When I was quoted $350.00 for a HVAC contractor to install the humidifier system, I decided to undertake the installation task. Installation is straight forward and the instructions are very easy to follow; but it does take a moderate understanding of electronics and a bit of plumbing know-how. The hardest tasks were cutting the opening for the humidifier on the furnace duct (my space was very cramped which highlighted the difficulties of cutting sheet metal), and running the connector wire from the humidistat to the humidifier through the crawlspace under the house. The instructions themselves on the reverse side were the template for cutting the opening. You must have a level to ensure a level opening or else the humidifier will not work efficiently. Once the duct opening was cut and trimmed, then the humidifier frame was attached. You need to make certain to slide the mounting frame topside clips first under the ductsheet metal and lift the unit to secure the bottom clips over the bottom of the opening. Then turn the two metal clips on either side of the humidifier to 90 degrees and tighten to the duct. (I used my better half's compact mirror to check the all of the clips on the backside) 6 sheet metal screws finished the attachment. The humidifier was then hung onto the mounting frame easily and just clipped into place. Once the humidifier was attached, I shut off the furnace electric feed at the fuse panel. I hooked up the electrical connections first from the provided 24 volt AC transformer to the humidistat, humidifier and then Aprilaire sensing relay (not included in the humidifier package) to the common (white) wire on the furnace blower. This would turn on the humidifier when ever the blower was on even when heat might not be needed. To hook the plumbing into the humidifier you have to install the provided saddle valve to the hot water pipe leaving the hot water heater; then connect the humidifier selinoid to the saddle valve with 1/4 inch O.D. copper tubing (not included in the humidifier package). The last thing I attached was a 1/2 inch I.D clear vinyl tubing that was routed to the A/C condensation drain pump. After I was certain everything was connected satisfactorily, I turned on the furnace breaker and opened the saddle valve. The initial setting on the humidifier was turned to max and then I could see water trickling down the drain tube confirming the system was operational.My observations: 1. Within the first two hours operation home humidity went from 26%R.H. to 37%.2. Static electricity shocks (very annoying) went to zero in a couple of hours.3. No nighttime bloody noses of kids.4. Dry skin seems to be healing (6 days so far)Two things that stand out that were not included in the package were the 24 volt sensing relay and 1/4" OD copper tubing. While these are minor issues, I did have to make a trip to the local hardware store to get the tubing and wait another day for the sensing relay. Overall, I have been very satisfied with the performance of the Aprilaire Humidifier 700M.One month after installation, I am still a very happy customer. House feels warmer now-thermostat is set 2-3 degrees lower than it was set before humidifier installation. I will check my heating gas bill this year vs last year to determine cost savings.Recommended Tools/Supplies for installation:Needle nose pliersWire stripper/cutterTin SnipsLevel1/4" copper tubing 5ft for my purposes**not included in package5ft ID vinyl drain tubing**not included in packageSensing relay**not included in package, but probably not necessary for units with an outside sensor included.Electrical tapeNov. 2016 Update****Humidifier working without skipping a beat. I change the water pad every year just before turning on the furnace. Humidistat setting is normally 35-40%. I can honestly say this unit saves us between 8-12 percent in heating costs. Picture shows how tight installation space is on our furnace-but doable. Darn picture keeps loading sideways-sorry