My building is essentially a single extremely large room. It's a 25'W x 45'L x 20' H concrete box, with an open mezzanine over the back 1/3 of the box. The HVAC system is gas-fired forced air, installed outside on the roof, and due to the foolishness of the builder, the heating registers are all at the ceiling level, except for one under the mezzanine. The air return is in the middle of the ceiling. The only water is also under the mezzanine.

EDIT: There are basically just two runs of ductwork. One comes from the roof-mounted HVAC unit, and runs down one side of the ceiling. I'd guesstimate it at 8" x 12" ish, and it has four registers along it. There's a single branch off the ceiling duct that comes down and runs along the underside of the mezzanine - flexible and maybe 8" diameter.

I've been looking to get a humidifier, and all the stand-alone units of a size that make sense for a space this size get pretty mixed reviews (and also require filling multiple times a day). Installing a whole-house humidifier at the furnace is not an option, due to its location.

My question is: can a whole house humidifier be installed somewhere other than at the furnace? My options: (expensive) run water up to the 20' ceiling and install on a duct up there. (easier) install on the one duct that's near water, under the mezzanine - but that's only about 25% of the incoming air.

  • You can get a "powered" unit which installs on a duct, several feet from the furnace. But running a small water hose is not that big of a deal. (The drain's a slightly bigger deal, but can be handled with a condensate pump and another hose.) Your bigger problem is that any humidifier needs to be installed on a fairly major duct.
    – Hot Licks
    Commented Feb 20, 2015 at 18:17
  • Thanks for the reply. I'll update the original post to describe the ducting. There are basically only two ducts. I'm not sure if the downstairs duct would qualify as "major" or not.
    – meeotch
    Commented Feb 20, 2015 at 22:05
  • I'm not sure it's so much a matter of will or won't work, but how well. And that of course depends on your humidity requirements (and how tight the house is). But look at the "powered" units by AprilAire, and note that some can be fed hot water, which improves function substantially, especially when installed on a return air duct.
    – Hot Licks
    Commented Feb 20, 2015 at 22:23
  • Put a self powered unit on any duct you want, so long as it is not a slave to the furnace.
    – Mazura
    Commented Feb 21, 2015 at 2:24

1 Answer 1


I suggest a swamp cooler - or as Home Depot calls them online 'Portable Evaporative Cooler.'

The big ones (which do come with wheels), a seem to do well in the reviews. There are many negative ones, but those seem mostly from people who do not understand what the product does. The are listed under the Air Conditioning heading, and talk about how much cooler they will make the room.

But you will not sell many with a slogan of 'These things toss water in the air, hope it sticks to you, and when the hot air, with no humidity from outside hits you, it will evaporate off your skin, and you will feel cooler'.

However, if your goal is to have humidity - even most of the negative reviews will sound good to you.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.