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 valve 6. 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. Level 12. Electric drill 13. 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 cutter 16. 13mm open socket wrench Shut 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.