Whole House Humidifier Install

Project by DylanC posted 11-17-2014 03:42 AM 13937 views 0 times favorited 4 comments Add to Favorites Watch
Whole House Humidifier Install
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Since it’s started getting colder and drier up here in Minnesota, I decided to put in a whole house humidifier. Last year we used a small table-top ultrasonic humidifier with mixed results, so the whole house unit will be a welcome upgrade. (Free tip: Don’t use soft water in an ultrasonic humidifier unless you want a fine white powder over EVERYTHING in your house. Not sure what hard water will do.)

Purchased a Honeywell HE360 from a local big-box store. The specs on the HE360 say it will work for up to a 4,500 square foot home for newer construction (my house was built in 2008). I only have around 3,400 square feet so the HE360 is a bit overkill, but the next size lower was a bit too small. In the box are most of the items needed for a basic install, but my needs required me to spend a little bit more on a few accessories. I’ll get to those later.

First step was to tie into the plumbing. My house is all PEX, so rather than use the saddle valve included with the kit, I cut into a 3/4” line near the furnace and installed a 3/4” x 3/4” x 1/2” reducing tee and a ball valve. Also used a push-in type 1/2” x 1/4” OD reducer for connecting the included tubing. The picture shows the finished product. The loop in the tubing is intended to keep tension on the tubing from pulling on the valve/tee. I ended up having to buy a 50’ roll of tubing ($3-$4) because the 20’ that came with the unit was just a bit too short. I probably could’ve tied into my water at a different point and been OK, but it was too late for that.

Next I laid out the template on my discharge air plenum and traced it. I wanted to fold the edges of the sheet metal over, so I marked a secound line 1” inside of the template. I cut out the smaller hole with my jigsaw and use a (borrowed) sheet metal pliers to fold the extra 1” of metal back. The idea was to give a better finished edge and more metal for the sheet metal screws to secure to.

First problem: The instructions say to cut out the opening with a snips and leave the unfinished edge. The humidifier base has clips that are supposed to slip over the sheet metal to hold it in place. By folding the edge, I made it too thick for the clips. Also, it was a very tight fit on the width of the base. In order to make the base fit in my opening, I had to trim out the clips on the top and bottom of the base and press it ‘firmly’ into my opening. Probably could’ve/should’ve made the opening 1/4” larger than the template. Drilled a few pilot holes and finished with 6 sheet metal screws. Base ended up very secure.

Next were the controls: the pressure switch and humidistat. To simplify wiring, I mounted these very close together on the return ductwork. It is important to try and keep the humidistat accessible for adjusting the setpoint. The pressure switch can really go anywhere as long as the tubing can reach both the supply and return ducts. Cutout for the humidistat was cut using the jigsaw.

Connecting the control wiring to the humidifier was a bit of a chore. The wire was too small to just twist and wire-nut, so I ended up soldering the wires and putting a crimp connector on to insulate them. I ran the wire from the humidifier to the ‘stat and switch along the corner of the supply plenum and then covered with aluminum duct tape to make things look a bit cleaner.

Then I installed the plugs, elbows, and tubing for the pressure switch. I drilled the 3/4” holes with a borrowed uni-bit. I installed the pressure plugs as close to the return and supply of the furnace as possible. This ensures the largest pressure differential for the switch. Not sure if that matters, but I did it anyway. You can see them in the picture of the finished install. The return plug is just an inch or so from where the duct connects to the furnace and the supply plug is just left of the actual humidifier unit.

Almost finished, I next ran my drain tubing into the top of the PVC drain for my AC coil…just over a foot away and enough slope I won’t have to worry about water sitting in the tube. The last step was to extend an electrical circuit and install a receptacle close enough for the cord to reach. This worked out well, because I also needed a new outlet for my chest freezer which has been on an extension cord until now.

And voila! The finished install…

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4 comments so far

View dbray45's profile


157 posts in 2181 days

posted 11-19-2014 11:59 AM

You did a very nice job on this, good work.

-- Love woodworking and fixing most anything

View JakeHatfield's profile


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posted 02-23-2018 06:02 AM

There are lots of things is for good working and it leads for ideal return in order. The process of good and supportive action works in order for go ahead in stylish return. The source of best essay writing service is for good return for working.

View MelBrandle's profile


24 posts in 1942 days

posted 03-26-2019 03:27 AM

Thanks for the tip on the soft water because that was my initial thought for our humidier kit. I guess trial and errors would most certainly help to determine what materials best suit our setup at home as every home’s environment differs.

-- Mel Brandle, https://www.supereasystorage.com.au/locations/adelaide/

View markgrogan1's profile


12 posts in 370 days

posted 04-03-2019 04:10 AM

How much electricity does that thing eat. I can imagine that it definitely helps with the breathing and t he lungs around the house but I reckon that it probably saps up your energy during those months even more!

-- Mark Grogan, https://www.supereasystorage.com.au/locations/wollongong/

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