How to Install a Whole-House Humidifier | Ask This Old House

How to Install a Whole-House Humidifier | Ask This Old House

so this is the heating system up here all right let's see what you got so you have an air handler that has a blower fan inside of it's going to push the air up into this duct you can see there's flexible supplies on each end right here and those go down into the second floor now all the air that has to come back to be reheated or riku is going to come back through these flexible returns right here to the bottom and the cycle repeats now this is not a gas furnace or an oil furnace it's actually a heat pump and for that use these refrigerant line sets that are connected to a condenser outside to either heat the air or cool the air now today we're going to introduce a humidifier there's a couple things we need we need water now I can see right here you've got a water heater up here that's great we need electricity it looks like you got plenty right here and we need to drain okay and I can see there's a drain already in place right here that's the good news but the manufacturer of this steam you mid afire wants to be sure we introduce steam in the right place when I look at this duct imagine what happens when that fan is on the air pushes up here and it hits the back here and against the air very turbulent very confused if I put steam right here there's a good chance that all that condensation could fall right back into this and we don't want that that's excellent well actually it is but we're going to have to do is to change this ductwork and modify it so it goes over to one side so we can introduce the steam and all the air goes by in a nice organized way great this is a pretty big job so I asked technician Ryan Gunton to lend a hand we'll start by detaching flexible supplies then we'll disconnect and remove the old sheetmetal trunk and build a new this drive fleet will hold these two pieces of strung together tight that's why they call it ten knocking so we have a series of flexible supplies that we have to connect into our main trunk and for each one that I'm going to use one of these this is a take off it has a balancing damper inside of it right here and it has a sealant or adhesive right here it'll make a nice tight seal to the duct I want to cut a perfect four inch hole and for that they have a special hole cutter you can see it's a pivot point right here and there's a special drill bit right here that cuts on the side now I put it down inside all right how's this fit Ryan what's good over here good so this elbow has these louvers in them they're called turning vanes that'll help that air leave the air handler and really smooth out in our new trunk right here we'll attach these 12-inch takeoffs just like the smaller ones using an adhesive strip and self tapping all right soon you've made a lot of progress up here remember your duct work you stick them off the top and went both ways now we come off come in one direction here a nice solid trunk you can see the flexible connections are made and this is your new whole house humidifier right here great let me just pull the cover and the way it works is there's a reservoir right here and that is half filled with water right there and there's an electrical element inside of it now that element will get the water so hot that'll turn it from water to steam and leave out through this insulated hose okay this will automatically refill itself oh okay so is there anything I need to do to maintain it not really the only thing is if you had high minerals or hard water over time that electrical element might get burned out like a coffee machine does but that element is replaceable okay so now here is the wand right here now the steam is going to come up through that hose and these little holes will be sitting right in the air stream and the air will go across it and absorb every bit of that steam into the air okay so we have to think about the right location I want to be down a couple of feet we'd like to be up about a third of the way and I could go right here but where I'm going to put is actually on the backside right here because the great location for the emitter fire is right here that'll minimize the amount of run for this hose once I get it mounted we can run the water great we've cut in on the cold water feed to the water heater with a separate shutoff and a quarter inch copper feed to our new humidifier so Ryan this units got a drain right it does which is very important because this unit will sense the amount of minerals that build up in the cylinder and if he gets to be too high it will flush the cylinder that's great so it'll help keep it clean they will all right so we'll connect that drain down into one of these drain connections here that's correct perfect all right sandy we've made our final connections here's cold water into the humidifier here's the drain leaving the humidifier got this insulated hose with steam going to the wand we also brought a licensed electrician and he had a separate circuit right here and that gives us 220 volts from this panel over to the unit and we've also got a couple of control wires into the back oh ok so how do we control it well there's a couple of safety devices that are up in places you don't to worry about one is an air proving switch we want to make sure that you mid afire doesn't come on unless the fan is on ok and the other is a high limit we want to make sure they're not too much humidity is up in this Doug Murray but those are hidden away you don't need to worry about the control you do need to think about is down the first floor so Cindy down here is a device that everybody knows it's a thermoset since its temperature right above it is the new device called humidistat in a sense the humidity in the building so you'll set it to the right level and we'll bring on the emit of fire and it actually bring on the fan as well ok so what level did it keep it at I like to see 35 to 40 percent I agree with that okay but you'll get to know the right level I also want to cost you though you don't want to set it too high because in a nice tight insulated house you can have actually mold if you put too much of it in there no okay you know what that No well thank you guys so much we really appreciate it and I know we'll be more comfortable if we can get rid of the portable humidifier yes you can you


  1. I've found out this review today: . I think it's a great buying guide for starters

  2. Copper for the drain and a 220v circut for a humidifier? I guess if it calls for it, but man a tiny heating element like that needs 220v? PVC that drain line all day, she already had pvc drains on the a/c unit anyway and to use copper for a drain is just a waste of money. Good job though, not a really ideal installation location, they are hardly that neat/clean. But it got the point across.

  3. If a home owner installed the steam humidifier featured, it would instantly void the warranty. Those things are not cheap. Get a $150 one from home depot or call a professional when you're dealing with that much money.

  4. so many things wrong with this. first the unit is in the attic so shouldn't the trunk be insulated! its going to sweat! second the humidifier should have separate drain, why you ask well in the winter time when the humidifier drains it most likely in the application that they installed it will most likely go out side and freeze it should have a dedicated drain going somewhere in the home. also so tired of seeing duct work done wrong no step down uneven pressure its appalling.

  5. Licensed electrician? No support for the cable coming out of the furnace cabinet. The protective conduit sleeve is not connected or supported. Seems to be NM cable, as can be seen by the NM cable connector, which would require a means of protection, but still needs to be supported. It's unclear if the cable goes into the sub panel, but if it does, again, no support. No way the electrical work on this project was inspected.

  6. Ok. So uninsulated duct, poor designed plenum, brick feet, adding electric to the air handlers circuit, all make for a nice setup? You better put more lipstick on that pig cause that is one crap install.

  7. Nice big clean attic with water nearby. Now do a typical installation, you know, tiny attic/crawlspace, no power, no water, cobwebs, dead mice, leaky toilet drain, etc, etc, etc.

  8. flexduct… the hallmark of a crappy HVAC guy. Going right to a trunk at a 90 instead of throwing a curve in is another sign. That air runs right into a wall at the start, then has to snake around to get anywhere. If your HVAC guy takes out flex pipe , call a new one.

  9. terrible duct system, no insulation, way to long flex duct,not sealed, hot cold or hot will that attic get? freezing conditions?

  10. What I really wanna know is why that plenum isn't insulated? Why aren't the plenum joints taped and masticed or mastic taped? How about if you make videos about home improvement, you actually do it right. I used to love watching this old house when I was a kid. Now that I do HVAC, Electrical, and Plumbing for a living I see how full of bologna they are most of the time. Can I get the business name/location and license for this HVAC contractor? There are repercussions for doing sub par work.

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