Hanging a dehumidifier from the ceiling?

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Forum topic by Vintagewood1960 posted 07-31-2018 01:49 PM 2066 views 0 times favorited 12 replies Add to Favorites Watch
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52 posts in 1104 days

07-31-2018 01:49 PM

I’m setting up a 30×30 ( insulated except for two bay doors) shop and live 400 ft from a large body of water (Lake Lanier) in the Gainesville Georgia area. I have purchased a 70 pint Dehumidifer and separate condensate pump and the larger Jet air filtration unit AFS 2000. To save on floor space and to have less dust hampering the operation of the dehumidifier I’m thinking of building a suspended platform in the center of the room and placing the dehumidifier/condensate pump (fed to outside) on the platform. I also want to orient the air filtration unit so it is filtering the air before the air is being sucked into the dehumidifier. (Orient the Jet unit intake at 90 degrees to the intake of the dehumidifier)
Will the dehumidifier be effective 7 feet in the air ?
Would either the dehumidifier or the air filtration unit have a problem competing for the air around it. (I would think there would be plenty of air to go around but hey, Science is weird.)
I lurk more than post on this forum and really appreciate all that I’ve learned lurking. Thanks in advance.

12 replies so far

View Fred Hargis's profile

Fred Hargis

5928 posts in 3100 days

#1 posted 07-31-2018 01:55 PM

I don’t think you will have any problems with doing it, but I’m not sure about having the air filter blowing into the dehu. I wouldn’t do it that way, since I would want to run the dehu around the clock, and the air cleaner only when needed.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Steve's profile


1697 posts in 1189 days

#2 posted 07-31-2018 02:00 PM

Do you need the dehumidifier? What’s the humidity % currently in the space?

I would think it would be more efficient on ground level, but I see some units are made for hanging from the ceiling.

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52 posts in 1104 days

#3 posted 07-31-2018 02:10 PM

90/95 percent humidity in summer and still quite high in winter months.

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52 posts in 1104 days

#4 posted 07-31-2018 02:13 PM

I was thinking of orienting the intake of both machines at 90 degrees. But maybe the output of the filter to the input of the dehumidifer is the way to go.

View RobS888's profile


2635 posts in 2452 days

#5 posted 07-31-2018 02:18 PM

If you hang it, you probably won’t need the condensate pump. Most of them have a hose bib on the back fro continuous operation, I have one elevated about 10 inches in the garage and the water runs fine down and about 6 feet to an outside sump. I do have it tilted back about 1/4 inch to make sure it flows the right way. If you hang it that high the water should run pretty far. I have a 3/4 inch pex line running from a humidifier attached to the side of a heat pump maybe 5 feet high in the basement to a sump about 40 feet away.

I’m on my 3rd dehumidifier and I found that the simpler the controls the better, simple dials from now on. LEDs and touchpad buttons let me down.

-- I always knew gun nuts where afraid of something, just never thought popcorn was on the list.

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52 posts in 1104 days

#6 posted 07-31-2018 02:32 PM

I already have a pump and want to feed the hose above the unit running in the 2nd floor joist. So I’ll need 2-3 foot of lift.

View clin's profile


1076 posts in 1603 days

#7 posted 07-31-2018 03:25 PM

I’d certainly face the output of the filter towards the dehumidifier. But I wouldn’t put it too close or try to couple them n any way. The Jet filter moves a lot of air and has three speeds. So it’s flow rate is not likely to match the dehumidifier flow.

And if the filter is too close, and effectively forcing air into the dehumidifier it might disrupt the airflow inside the dehumidifier.

I think you’d get better overall airflow if you position these unit at opposite ends of the shop. Having two things moving air at two places will move the air better than having both in the same place.

And if it won’t restrict the airflow too much, perhaps rig a furnace filter on the intake of the dehumidifier. Then it will do some filtering as well.

-- Clin

View lumbering_on's profile


578 posts in 1097 days

#8 posted 07-31-2018 03:27 PM

I haven’t done the calculations, but off the top of my head, hanging the dehumidifier should be better than keeping it on the ground. As strange as it sounds, moist air is less dense than dry air, so any air coming out of the dehumidifier should ‘fall’ to the ground, and push more moist air up.

View PCDub's profile


153 posts in 851 days

#9 posted 07-31-2018 03:29 PM

Humid air is lighter than dry air, so hanging a dehumidifier should not be a problem!

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52 posts in 1104 days

#10 posted 07-31-2018 03:55 PM

Anybody have any experience with rigging a furnace filter on a dehumidifier. I would imagine you would have to keep a close eye on how restricted the filter is getting. Has anybody ruined a dehumidifer with this method.

View CaptainKlutz's profile (online now)


2245 posts in 2101 days

#11 posted 07-31-2018 04:11 PM

Part of answers to your question depends on type of dehumidifier you bought?

De-humidification equipment can exist almost anywhere in the space, or in the air handling system supporting the HVAC system. Only thing that needs to be prevented is choked airflow inside room, that prevents moist air reaching the dehumidifier.

High efficiency dehumidifiers often have internal filters to prevent dust/dirt from clogging heat exchange fins. Dehumidifiers need to run 100% of time in a moist environment. This puts tremendous amount of airflow across filters, and in a dusty environment will require constant filter maintenance to avoid freezing the heat exchange coil due not enough air flow. Changing extra filters could get really annoying with unit hanging from ceiling?

If I wanted to permanently install dehumidifier in wood shop, I would use a duct-ed unit and look to mimic the installation of a whole house dehumidifier unit. They are made to work stand alone, in ‘bypass mode’ of a home HVAC system. I would use the Jet multi-stage air filtration unit as my ‘central air conditioning’ in the design. Would plumb the dehumidifier inlet air directly (and only) from exhaust of air filter. This would allow the dehumidifier to pull fresh air from air filter when the dust filter fan is not running, and provide only one filter system that needs maintenance.
As another post stated, portable dehumidifiers can be unreliable due cheap controls. Whole house unit is designed for 24/7 20 year service, with only filter changes to keep it working. One challenge with whole house unit is location/type of humidity sensor and control unit, as this is built-in on portable units, but always included with whole house unit.

There are a tremendous number of variables to consider when dealing with humidity control. WWW has plethora of DIY sources, such as this one.

Hope this helps.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View jonah's profile


2092 posts in 3905 days

#12 posted 07-31-2018 05:54 PM

The reason that humid air is less dense than dry air is that water vapor (H2O) is lighter than O2 and N2, which make up 99% of our air. So the more H2O displacing O2 and N2, the lighter the air.

It’s also part of why you can’t run as far or as fast in humid air as you can in dry air – there’s slightly less oxygen available to your lungs in the air.

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