dehumidifier in shop

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Forum topic by jdh122 posted 05-31-2016 11:41 AM 1129 views 1 time favorited 7 replies Add to Favorites Watch
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1039 posts in 2962 days

05-31-2016 11:41 AM

My shop is in my basement and in our climate here I have to run a dehumidifier from mid-May to mid-October in order to make my basement livable and to avoid rust on all my tools. The dehumidifiers I’ve bought don’t last more than about 2 years, and I suspect that the dust in my shop is one of the reasons. I’ve ordered a new one that is supposed to arrive tomorrow (a larger, more expensive brand-name one). Just wondering if anyone has ever tried to add dust filtration to a dehumidifier. I suspect that the thin washable filters they come with aren’t up to the challenge of a woodworking shop (I have dust collection and a ceiling-mounted air filer, but still…). I was wondering about buying some filter fabric and wrapping it around the intake grill of the dehumidifier. Is this a bad idea? Am I just destined to keep spending a few hundred dollars every couple years?

-- Jeremy, in the Acadian forests

7 replies so far

View OSU55's profile


1862 posts in 2134 days

#1 posted 05-31-2016 12:09 PM

I suspect you are right about saw dust blocking airflow causing the early demise of your dehumidifiers. A little inspection of the failed machines would answer the question – do the fans still work? Are the evap and/or condenser coils blocked with dust? Water drain blocked? The filter on mine (not used in the shop) is fairly coarse and wouldn’t stop fine dust.

Do you ever blow the dust out? That would help. The problem with added filtration is blocking of air flow, causing the unit to overheat. Added filtration will need to be checked often and replaced or cleaned to preserve airflow. In the end, added filtration may or may not get the unit to last longer – you’ll get to test to find out. A pleated filter would be best if there is a way to fit one on the unit.

View TheDane's profile


5524 posts in 3807 days

#2 posted 05-31-2016 02:08 PM

I vacuum the filter when the warning light comes on … compressed air would likely damage the thin flimsy filter.

I do blow the fan out every so often and try to keep it as clean as possible.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Fred Hargis's profile

Fred Hargis

5094 posts in 2638 days

#3 posted 05-31-2016 02:08 PM

My experience with them is that the are not all that long-lived anyway, so while dust may be an issue….I think you are just having a normal experience. That doesn’t mean you shouldn’t try the filter fabric anyway. You did mention that the new one is an “expensive brand name one”. I think you’ll find it will last longer just for that reason.

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

View CharleyL's profile


223 posts in 3509 days

#4 posted 05-31-2016 02:33 PM

My previous shop was in the basement of my house in the Hudson Valley of New Your State. Humidity was a huge problem and my dust collection was a shop vac. I had a good brand name dehumidifier that ran almost constantly as it was connected through a trap to the sewer line. About two times every Summer I would disconnect it and take it outside, then blow the dust out of the coils and internal components, then used a refrigeration coil cleaner (about like Fantastic brand household cleaner) sprayed onto the coils and then rinsed off. I would clean the inside and outside of the cabinet with it too. I would then leave the unit sitting outside in the Sun to dry off for a few hours before returning it to service. That Dehumidifier was about 12 years old when I moved away, and it was still running.

I think a frequent and thorough cleaning would be better than putting a filter over the air intake. The fans in these dehumidifiers aren’t strong enough to pull the air through an even slightly dirty filter. You will loose a lot of efficiency with the filter installed. This is true for dirty coils too. Take the cover off the dehumidifier and clean the coils well a couple of times each Summer and it should work well for many years. The Fantastic Brand cleaner should be adequate to clean the coils very well, but rinse them thoroughly after letting them soak for a few minutes. Keep the water and cleaner out of the fan motor, electrical junction boxes and control unit You might need to do this cleaning more often if you spend more time in your shop. My job and large family kept me from working in my shop more than I wanted back then.


View JBrow's profile


1366 posts in 1064 days

#5 posted 05-31-2016 02:36 PM


I know nothing about de-humidifiers, so I cannot say whether wood dust is killing the machine. But it does seem like it is a good idea to keep dust away from the machine. One idea is to build an enclosure in which the de-humidifier sets. The enclosure could be a plywood box with one side designed to accept a large furnace filter. The 3” and 4” thick filters can capture a lot of dust before clogging, but a 1” filter would also work. If the filter covered opening is large enough, the de-humidifier should get plenty of air. An opening for exhausting air from the de-humidifier would make the whole contraption work better, but engineering the exhaust to keep dust from entering, depending on the de-humidifier’s design, could be difficult or impossible. In this case, if the furnace filter is large enough, I would think air should be able to both enter and exit the enclosure through the filter covered opening. Being a high humidity environment, standard plywood probably would not hold up well, therefore marine grade plywood could be a better choice.

View RobS888's profile


2490 posts in 1989 days

#6 posted 05-31-2016 03:25 PM

I just purchased my third a few months back. They seem to last 2 years at most. The last one lost its mind and I’m now using a simpler model with just a dial. No displays or soft buttons. It has a low back mounted hose connection. I think the best would be connected to the bottom back of the bucket. The last one had a shallow pan that filled with algae and plugged the hole and leaked. I suspect the pan was to prevent the sound of water dripping. Sheesh what a bad approach for my use.

I purchased this unit last summer, and it runs pretty much every day.

I purchased this from amazon for $169.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View jdh122's profile


1039 posts in 2962 days

#7 posted 05-31-2016 04:07 PM

Thanks for the great advice everyone. It seems like it would be a bad idea to add secondary air filtration and better to just vacuum and clean it out more often (I’m not very good at looking after regular maintenance, though). And just accept that it’s basically a consumable.
I’ve never had the fan fail on one, it seems to be the compressor. The Delonghi I just ordered has a 2 year warranty for the whole machine and a 5 year warranty for the compressor. Supposed to arrive tomorrow.

-- Jeremy, in the Acadian forests

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