I read many reviews on this both good and bad before purchasing. I spoke with a handyman about helping me install one, he said Aprilaire is a good brand. After comparing EVERYTHING, I decided on The Aprilaire 800, glad I did. Shipping was super quick. We live in Utah and winters are brutal, near zero humidity and my wife has a serious problem with low humidity. Overall, installing the unit was not complicated, but it took us 4 hours to run the electrical wire, and about 4 hours to install the system. Installing the Electrical It took us several hours to run the 220V line from the basement to the top floor, but we did it without tearing up the house. We had to consolidate two smaller breakers to free up a space for the new 220 breaker. We ran the wire from the break box into the ceiling and upstairs through the walls. From the floor in the furnace room (two floors up), we ran flex conduit from the floor directly into the unit and connected the wire through the conduit to the unit. Installing the Main Unit First, we mounted the unit to the wall and hooked up the 220 power. Next we tapped into the cold water feed above the water heater by installing a copper "T" and a new valve and connected the unit water feed. Next we tapped into the the drain line for the A/C by installing a PVC "T" and connected the unit drain line. Finally, we drilled a hole in the side of the furnace outflow duct above the furnace, and inserted and mounted the steam jet into the duct, then connected the steam line from the unit. Installing the Controller You have to install the humidistat controller on an inflow duct as that's where it measures the humidity. Luckily, there is an intake vent on the opposite side of the wall so we mounted the humidistat controller on the wall inside the furnace room about 6 feet from the furnace. We drilled a hole in the drywall and through the metal duct, and mounted the humidistat controller over the hole. Next, we connected the wiring from the humidistat controller to the main unit. Next, we connected the second wiring from the humidistat controller to the furnace. We had a little trouble figuring out how to connect the wiring from the controller to the furnace to get it to operate the way we wanted, but with a little persistence and two of us reading the manuals, we finally figured it out (we wanted the humidifier to operate the furnace fan by itself and independently instead of only operating when the furnace is running - there are several configurable operating options). Operating the Unit We installed the filter/heater cartridge into the main and fired it up. The unit ran through the test cycle, filled with water, drained, made some noises and turned indicator lights on and off, but when it finished the test cycle, nothing happened. We thought we had done something wrong, but based on the way we had configured it, the Aprilaire unit will wait for an hour to start up the furnace fan unless it comes on by itself. You can preempt that by turning on the furnace fan manually for a few seconds. Once its running, it will control the fan itself. So you have to either wait for the furnace to run by itself in order to trigger the unit to operate, or you can force it on by turning on the furnace fan manually. We turned on the furnace fan which triggered the unit to start up, so we shut off the furnace fan, and the Aprilaire unit turned it back on by itself. Within less than a minute, we could feel some heat through the steam line so we knew it was working. My house is 2 stories about 2,800 ft sq. The temperature outside was about 10 F (-12 C), we keep our inside temperature at 78 F (25.5 C). The humidity was 4% before we turned on the system. The humidistat controller has a range from 0 to 7, we set it on 4. It took the system about 6 hours to bring the humidity up to 30% and we could feel the humidity in the house, it was great. The unit shut off at about 38% humidity, so we cranked it up to number 6. We ran the system all night, and when we woke up, it was 66%. It felt like Florida in mid-summer, oh yah!. Many of the windows were fogged up on the inside, some had water all over the window sills. OK, we went a little crazy, 66% is too high. We don't run the system at night after we go to bed anymore because the air is cool coming out of the ducts when it's just the humidity running, so we crank it up before bedtime to about 55%, and then shut it off. The humidity by morning is usually around 35% to 40% and we keep the house around 35% and 40% during the day until just before bed. We've been using this since September, it's now March (7 months). We couldn't be happier with this system. I bought a spare filter/heater cartridge in case ours stopped working, but so far, we have not used it. This thing automatically fills and purges the filter once in a while (not sure exactly how often it does it), but so far we've had this running pretty much all winter, and it has worked flawlessly.