Whole house humidifiers


It gets very cold where we live these days, and our house gets extremely dry. Dry enough that we get extremely itchy dry skin, and I know it’s not good for wood furniture, etc.

We’ve talked about getting a whole house humidifier installed, which we’ve had in houses in the past. However, I see online people say you’ll ruin your vents and get mold in them etc. if you’re blowing moisture through them.

On the other hand, these are the same vents that the A/C pulls humid air through during the summer, right? And our humidity during the summer can be a lot higher than where we’d set the humidifier.

Anyone have any expert advice on this?



Why not just have a few spot humidifiers you run in common areas? Why go whole house, that seems complicated / expensive / risky?


We’ve got a couple of portable humidifiers, but they don’t humidify the whole house, and you have to constantly refill them (thus when we’re out of the house at work, or away for a weekend, etc. they stop humidifying.)

The nice thing about the whole house humidifer is you simply set a humidity level for the house, and it works.


We run 2 small ones in the bedrooms. Between them and the shower moisture in the morning the house in the winter is usually at 40-45% humidity.


What Wumpus said. You’ll get the most benefit from just one in your bedroom. The other common areas don’t really need it, unless you are in any of them at least 6+ hours a day.

We use one that will blow both heated and cooled moisture, which makes it really nice for use most any time of year. Since I’m also a fellow dry skin and skin problem sufferer, I would encourage you to add a couple of things not home related: up your water intake per day during the winter, and consider a skin supplement that contains common items you might miss in your diet that promote healthier skin. Many of these are commonly marked, “for hair, skin and nails.”

One thing not mentioned that they might ask you though @JeffL, is your home well insulated, and are you blocking outside air well? That’s actually one of the reasons why the air in your home in winter gets so dry, and so wet in summer… Otherwise your home should stay a lot more stable in humidity.


I have been known to quip that west Texas is the land of two seasons; light brown and dark brown. Minnesota has all four seasons, but two are marked by keep the humidifier tank filled and keep the condenser (dehumidifier) tank emptied.
I have tried several for the first floor. This is my keeper. I turn the fan to low when I am watching T.V. and its not too noticeable. The only “gotcha” is the overfill relief hole is in the back and the tank marker is a bit hard to see. I only made that mistake once ;) There was appreciable scale on the wicking media when the indicator signaled that it needs to be changed so have an extra on hand.
Upstairs I have a small ultrasonic humidifier. Any of them are fine.
Between the two I am able to keep the relative humidity in the house at about 45% even when it is below zero outside. Its nice not to have the family, the leather, and the wood desiccated in the winter.


Whole house humidifiers shouldn’t be making mold in your vents… not sure who suggested such a thing.

I’d definitely suggest getting one. Hell, you can install it yourself pretty easily. It’ll only run you around $150.

Way easier than maintaining a bunch of separate little units.


Read the thread title as “White House Humidifiers”, and wondered if there was some new scandal involving home appliances… “Trump blames Obama for air being too sultry in Oval Office, calls it Obama-air”


I have one in my house, attached directly to the furnace. It was there when I moved in, so I don’t have great insight into what’s available. Minnesota winters are incredibly dry, especially once you warm the air up, and it definitely does make a difference.


I installed one myself a few years ago (and I’m not particularly handy, if you’re wondering about the difficulty there). Glad I did. I had never heard of mold problems, but I live in Colorado where everything is generally too dry all the time to foster a lot of mold. Our furnace installers years and years ago recommended one, but we skipped it because of what we were already paying for the furnace itself. After spending years filling up a humidifier nightly in every kid’s room (3 of them), it started to make a lot of sense. It doesn’t do exactly what a room humidifier will do–you still might want one of those if you have very specific medical needs it helps with. Mostly, the central humidifier just compensates for the humidity that’s leeched out by the furnace itself. But you definitely notice the difference when you first get it set up.

I’m rambling, so let me know if you have specific questions.


How dry do your houses get in the winter? My apartment gets down to 5% humidity or so, but that’s because I live in NYC and am forced to keep my windows cracked even in the dead of winter or my apartment will be like 90F.


As a woodworker, I’d like to clarify that solid wood naturally expands/contracts with humid/dry air respectively. Most furniture these days is made with plywood covered in veneer, and these should not be impacted at all.

And only poorly built solid wood pieces that were not built with wood movement in mind will be impacted. A good woodworker will take wood movement into consideration & the joinery will account for this.

However, many budding woodworkers don’t account for this & you get to see joints blow apart, or pieces crack because you have wood going in one direction trying to contract, and wood connected to it perpendicularly where it is not expanding (wood only expands/contracts along it’s width and not length).


Dude, that’s nuts, and not healthy.

Normal humidity in a desert like the Sahara or Mohave is around 25% during the day.


Typo-- I meant 15%, and it never gets lower than that. But 20-25% is very common in the winter.


My experience with whole-house humidifiers connected to the furnace is that they work fine, provided you stick strictly to a schedule of regularly disassembling them down and cleaning them thoroughly. That means once a month during the heating season. If you let the cleaning get away from you, they break down pretty quickly.


Heh, ok.

15% is normal, but again, much drier than a desert, and not really ideal for humans. That’s why whole house humidifiers are nice.

Generally, I think the ideal is around 30%.

Was gonna say though… at 5%, you’d kind of die eventually… or at least, you’d need to be chugging water all the time.


Ideal humidity is 40-50%, actually. I do get dry skin and cracking calluses at <20%. Delightful image, I know.


In which Armando realizes he has never checked his apartment’s humidity.

I figure it’s gotta be pretty high, cuz even hyper processed sliced sandwich bread molds like a motherfucker in my place.


Someone needs to tell my mother this. She leaves the AC on because she’s convinced it’s better for the wood in the house. I’m like, this stuff is made to stand the elements, seems like a really dumb design.

Wait I’m confused why is there an Armando picture here… are you replying at the same time??

edit: yes you were.


Correct! Anyone typing while you’re typing shows up at the bottom :)

Or maybe it’s because I was watching you ;-)