Workshop Dehumidifier

[paris_tj]

I am looking for a decent cheap dehumidifier for my shop. I am in NE Texas and so far my shop stays between 35% and 70% humidity. usually 58-65%. I am trying to keep my tools from rusting and my CNC Mill and lathe.

What do you recommend?

I was thinking about one of the $250 one from HD. My shop(30'x x40' x 10' fully insulated) will also have shortly a 2.5 ton A/C unit. It will only run when I am in the shop I mostly weekends and maybe some evenings.

Would there be advantage to maybe get a sensor to turn on the A/C unit to assist in humidity? I figure that may cost more to run, than a cheap dehumidifier.

 

[greenbank]

I'm running a 50 pint unit in my "cold" side (23 x 35) and it got the humidity down from 85% to 70%, but it's not making any progress beyond that. My warm side, same size, seems to stay around 60% with no conditioning.

Remember that a dehumidifier is essentially a small fridge, so I'm not sure it's any more efficient to run than an A/C unit. Dunno.

 

[paris_tj]

Thanks, I am lost on this subject so I am hoping for some good help here.

 

[Lippyp]

I'm running a cheap EBAC dehumidifier that I picked up from ebay. Its only in a small single garage maybe 8' x 20' bit its a **** sectional concrete pre-fab job, unheated with a tin roof , no insulation and a leaky door. When it got cold and damp it used to rain inside there was so much condensation on the inside of the roof, now since using the dehumidifier I haven't had any condensation. Its pulling about a gallon a day when its damp outside. Its is importnat though to size it to the space, too small and it won't make too much of a difference.

 

[SMLDONZI]

I run 2 45 pint units--one on each side of heated and insulated 1500 sq ft garage. They keep it about 40 % humidity. Well worth it to protect tools and old cars, etc.

 

[paris_tj]

I was thinking of getting one of the 70 pint ones for my 1200 sq ft, so with regards to yours SMLDONZI, that should be close enough I think.

 

[SMLDONZI]

That ought to be perfect. I would prefer to have one big one but I already had the two. One big one is more economical I'll bet too.

 

[paris_tj]

That ought to be perfect. I would prefer to have one big one but I already had the two. One big one is more economical I'll bet too.

Did you notice any increase in your electric bill when you started running them?

 

[bd8134]

I had a dehumidifier that I bought from HD, lasted about 3 years, can't remember the make. It worked ok at sucking the moisture from my garage but was very noisy. This year it was only collecting a small amount of water but the still the dreadfull buzz/noise.
I have now bought this unit, http://www.amazon.com/gp/product/B0034G4OB8/ref=oss_product A lot quieter and seems to keep the humidity level a lot lower and a lot more consistent.
I could not say if it uses much electricity, when the cars are wet in the garage it does run a lot.

During the summer I use the central air to remove the moisture. It has a dehumidify setting which causes the blower motor to run slow. The water just pours out of the drain.

 

[pirate]

I have a 25 pint Samsung Dehumidifier in a 20' x 20' workshop here on the Gulf Coast of Alabama where you can almost stomp your feet and it would start to rain because the humidity is so high. I have no idea how acurate my guage may be but it always reads somewhere between 30% and mid summer 50%. It is enough so that things don't rust, the shop smells good. There is a noticeable difference between how hot it feels outside and the coolness when entering the shop just because of the humidity. I have no idea how old the unit is because I bought it at a garage sale. It has run virtually non stop for the last 9 years. I have a hose that runs to the outside so I don't have to empty the container.

 

[SMLDONZI]

I did not pay much attention to the electric bill. My thoughts on the economics are pure speculation.

 

[paris_tj]

Great Info. Thanks for all the help.

 

[Waiting]

I have one from Sears that works well in my cargo container/storage (it has a leak somewhere in the roof that I can't pinpoint).

 

[mad57]

drieaz lgr is a great unit but pricy ...but will be the last unit youll have to buy rebuildable and commercial.

 

[paris_tj]

Wow, I checked on that one you are right, pricey....

 

[35mastr]

Subscribed,I have the rain issue also with a metal roof due to humidity when its either real cold out or raining.

 

[pgreen]

I bought the biggest one I could find at Lowes a couple years ago. It isn't rated for the 2500 square feet that it is working in (mustless a 10' ceiling). I think it was rated for 1000 or 1500 sq ft. or something like that.

However, it works WONDERS if you keep things closed up. 90 degrees and 90% humidity on hot summer crappy days, it is still 55-60% RH in my shop. I usually keep it set at 55-60%. No condensation anymore on my mill table, steel work table, etc.

Be sure to get a hose for the drain, as it filled the little tub in it rediculously quickly. With a hose, it just runs automatically.

 

[Jackfre]

There is an alternative to the standard dehu's. I must acknowledge that I'm affiliated with the company, representing them in my home market. Having said that Tjernlund has produced a product called the Xchanger that deserves a look.

My personal experience with dehu's is that I spend +/- $250, DeLonghi, Kenmore, etc and they last 2+ yrs, cost a thousand watts/hr, heat the space they are running in and cost me $35 to get rid of them at the local dump.

The Xchanger is a new product, but they are a good outfit and my company has represented them since '59. I'd have one in my house but I just sold the place

 

[Vicegrip]

a dehu is just an AC with both ends in the same room. They take power to remove water from the air and in the end leave some heat behind. If you are going to have an AC installed why not just run it to lower the humidity and lower the air temps along with it? running a dehu in a conditioned space will only make more heat for the AC to remove.

 

[35mastr]

Well,Me and my 8 year old son went out to the shop this morning. After I opened the door the first words out of his mouth was "Dad, Whats that smell"
It was sooo musty in there that you could smell it. I ran to 2 Hd's Newark,Fremont. Then headed over to Costco,Walmart and then Fry's.
Found a Dehumidfier at Frys but it was 250.00 for a the same 70 pint that I purchased at Amazon for 179.99.

 

[35mastr]

If this dont do the trick. Then I am ripping that metal roof off and framining it out and putting a conventional roof on it this summer.

 

[paris_tj]

I could run the A/C but I figure that would be more expensive since it will only be used on weekends a little in the evenings. I don't need a extra $400 electric bill, the house bill is enough.....I finally got the interior sheeted with plywood this weekend, hopefully this will help now as it is more sealed up.

 

[35mastr]

Well it showed up yestardy. Its still running in the preset factory mode I just lowered the fan speed to low. I cant beleive how much water its pulling out of my shop.

Now my question is to those that have the Fridgidaire unit like mine. What is a good number to put it on when I switch it over to auto?

 

[paris_tj]

Keep me posted I am very curious. I hope to order mine in the next week or so. Just done a huge electrical service upgrade and having to wait for more funds to come in.

 

[35mastr]

Keep me posted I am very curious. I hope to order mine in the next week or so. Just done a huge electrical service upgrade and having to wait for more funds to come in.

It is well worth the money. I have pretty poor pitch and added a 20 foot 7/8 clear hose to mine so it will drain on its own. Went out this morning and saw no water coming out. I thought it was DOA. But then went to move the hose and noticed that ot was full all the way to the machine. Only 6 more inches to go and it would have backed up. I drained the hose at 9 am. It was starting to back up again at 3:30 this afternoon. So its really pumping out the humididty. I got the hose now set up so it will drain.

 

[35mastr]

Now I just need to know what setting to put it on so it can go to auto mode.

 

[6768rogues]

A dehumidifier is essentially an air conditioner that is a little more efficient due to its design. It has a compressor and cooling coil to condense out moisture, but then instead of blowing out cold air while an outdoor unit exhausts heat, it pushes the cool air through its condensing coil. Consequently, it is more efficient than having the condenser outdoors because it is being cooled by cold air coming off the evaporator. Either A/C or a dehumidifier will jack up your electric bill, but the A/C will jack it up more. A dehumidifier is kind of like having central air with the outdoor temperature low.

 

[35mastr]

Now I just need to know what setting to put it on so it can go to auto mode.

Anyone got an answer for this.^^^^

 

[paris_tj]

Well I ordered one today, so maybe by the end of the week I will have it test myself on my 30x40x10 shop.

 

[35mastr]

Mine been working real good. I just need to figure what humidity level to set it at. PG&E going to be nice to see this month.

 

[paris_tj]

I am going to set mine to 50% and see IF it can hold it and fine tune it from there. I have heard anywhere from 40-55% to keep tools from rusting, but I have not heard a definitive answer from anyone so far.

 

[Aberdale]

Well it showed up yestardy. Its still running in the preset factory mode I just lowered the fan speed to low. I cant beleive how much water its pulling out of my shop.

Now my question is to those that have the Fridgidaire unit like mine. What is a good number to put it on when I switch it over to auto?

I guess the answer is "it depends". I have a Frigidaire unit in my basement woodshop. I keep it set at 5, but in your case it will depend on the temperature, the source of humidity, and the size of your space.

I would just pick a number and see how it performs. If it stays dry, but is running a lot, I would turn it down until I noticed an increase in humidity, then turn it up one more notch.

Dale

 

[Aberdale]

Although I run a dehumidifier in my basement woodshop, I don't run one in the garage. I keep the garage heated so that the temperature doesn't drop below the dewpoint. That in effect keeps the condensation in check. I have a lathe and a mill in the garage, and just keeping it heated through the winter keeps rust away. In the summer, we get quite a bit of humidity here in Ohio, but I often like to work with the doors open which would defeat any progress made by the dehumidifier. I just keep the tools wiped down with oil to minimize rust. So far so good.

 

[Test Pilot]

I cant beleive how much water its pulling out of my shop.

Now my question is to those that have the Fridgidaire unit like mine. What is a good number to put it on when I switch it over to auto?

#### This was going to be my comment. You can't imagine how often you have to empty this thing. I'm going to set mine up on auto drain. I have mine set at 50% >>>>.

 

[paris_tj]

Well I got mine in from Amazon Friday and it is working nicely in my 30x40 x 10 shop.
I have it set to 45% as it shuts off when it gets t 50% at that setting...I would have expected it to shut off at 45% but no matter where i set it it will shut off 5% higher.

Here is a picture of what temp and humidity is in my shop Monday evening. I am very please. I am emptying the bucket about once a day. Soon to be plumbed into the same drain as my A/C unit. I am also pretty pleased with my insulation too, when it is getting down into the 30s at night and high 60's in the day it is holding pretty steady.

 

[OldCarGuy]

Total climate controlled garages are need for storing antique cars and keeping machinery and tools from developing surface rust. All five of my garages have central forced air heating and air-conditioners. Neither will keep the humidity down to a consistent 40%. Particularly in changing weather conditions. So I run a 65 pint dehumidifier in each garage year round. They have a humidistat that will shut them off once the humidity is below the set point... I have mine mounted on shelves near the furnace... To eliminate dumping the reservoir all the time, I have the condensate connected directly to a drain...

 

[trbomax]

Ive got 2 of them down in the shops,one in mine,one in hers. The shops do share central heat and ac,i have one in each because a lot of the time the blower is not running to circulate air between them. please note that this is not the vehicle shop,but the machine shop part. I have them set on 35% . They are "low temperature" units that will work at the maintainence temp. the shops see in the winter. Each "shop" is 1200 sq ft,and this works well.

 

[Vicegrip]

A dehumidifier is essentially an air conditioner that is a little more efficient due to its design. It has a compressor and cooling coil to condense out moisture, but then instead of blowing out cold air while an outdoor unit exhausts heat, it pushes the cool air through its condensing coil. Consequently, it is more efficient than having the condenser outdoors because it is being cooled by cold air coming off the evaporator. Either A/C or a dehumidifier will jack up your electric bill, but the A/C will jack it up more. A dehumidifier is kind of like having central air with the outdoor temperature low.

The down side is the temp in the space will go up with time as the compressor dumps heat into the space. Warmer air can and will pull more water. At least an AC can cool the space when needed with the free side effect of removing the moisture. Another down side t stand alone units is air flow, more so in a larger or complex space with lots of stuff in it. They don't move the air around like a central system can. Movement is key in overall efficiency. they have their place but often times fine tuning the existing system and moisture infiltration mitigation can go a long way.

Some of the mini splits have dehumidification cycles built in.

 

[trbomax]

The down side is the temp in the space will go up with time as the compressor dumps heat into the space. Warmer air can and will pull more water. At least an AC can cool the space when needed with the free side effect of removing the moisture. Another down side t stand alone units is air flow, more so in a larger or complex space with lots of stuff in it. They don't move the air around like a central system can. Movement is key in overall efficiency. they have their place but often times fine tuning the existing system and moisture infiltration mitigation can go a long way.

Some of the mini splits have dehumidification cycles built in.

I think that even with a central system there should be a couple ceiling fans. We have 1 in each side.

 

[jimmie jam]

if you are trying to remove the chance of rust forming on any tools or exposed metal for that fact the key is keeping the air moving in the space. simply keeping the warm (and humid) air moving will eliminate the moisture in the air from accumulating on the metal surfaces as the metal will be cooler than the ambient air. so, without the air in the space moving the moisture will "attach" to the cooler metal surfaces much like a cool drink glass forms moisture on it. i have been storing cars for years here in humid south Florida and have kept this problem at bay with $15 box fans from WM or KM, even in large buildings. if you also need or want to drop the temprature you will have to A/C the area. FWIW.