Garage dehumidifier???

[JOYO]

Anyone use a dehumidifier in their garage? In the name of preventing rust, it's something i've thought about for a while. I spend way to much time on my old cars.... I should do anything I can to protect them from rust.
I was visiting a friend in Wisconsin with an impressive motorcycle collection and noticed he had one..... Anyone had any experience with them? recommendations for someone on a budget?
I'm in Austin so the humidity isn't terrible, but it's there.
Drop some science on me!

-John Joyo...

 

[kbs2244]

If it is a storage garage, it sure won't hurt.
But if it is a working garage, one where you open and close the door all the time, it would be a waste of effort. All the dehumidified air would go out as soon as that big door was opened, and even in a 24x24, it would take days for a typical unit to bring a humid summer days worth of dampness down again.

 

[JOYO]

Thanks man!

 

[twostory]

I run a dehumidifier in my 2 car garage year round. (Atlanta, GA area)

Even when I open the door for the afternoon, it will dry out the air after I close the door. The only problem I have it the garage is noticeably hotter than the house is. The dehumidifier raises the temp of the 2 car garage.

Just buy a $100 dehumidifier, pipe the drain water to the outside and see how it works (not much money to try it). After you are up and running, adjust the humidity knob to make the unit only run when it is humid.

 

[Vicegrip]

Some mini split units have a dehumidify cycle that pulls water out without changing the temp in the space.

 

[snorvet]

I keep my detached garage dehumidified to about 60-65% May thru September. Works great as long as I keep my garage door closed as much as possible. Helps keep it cool too.

 

[JOYO]

Any certain brands you guys would recommend or have had good experience with?

 

[snorvet]

I have a Comfort-Aire from Ace Hardware. I think its the 30 pint.
I would recommend it. It was about $140.

http://www.acehardwareoutlet.com/(k14wcq55hiltsk45xjkwi1uj)/ProductDetails.aspx?SKU=43431

 

[GaryRoushkolb]

I have a humidifier in my shop and this spring and summer it removes about a gallon a day. I save the water for my wifes plants in the house.
I bought a unit from walmart on sale and it really keeps the rust off drills , mill cutters and tooling. We have a major humidity problem in Kansas this year.

 

[JOYO]

Thanks for all the great info fellas!

 

[Major Ramifications]

Get a low temperature dehumidifier. They work year round. Ebay would be a good place to look, as we sell hundreds of Kenmore dehumidifiers on ebay each year. The water can either collect in the build-in container, or it comes with a garden hose attachment that you could run outside or to a drain.

 

[PAToyota]

Have to say that I'm not too pleased with the Kenmore dehumidifier I bought a couple years ago. It was on sale and I had been using one I had for fifteen years - figured a new one may consume less energy.

Two years later the fan wasn't running this spring. Opened it up and found that whereas the old one had your basic switches for the fan and a humidistat, the new one includes a wonderful PC board of gizmos... Guess what seems to be bad (tested all the other components)? Guess what is no longer available as a repair part? Going to have to drag the old one out and start using it again - never did get around to throwing it away...

 

[JOYO]

Maybe a dumb question, but is there anything that you don't want to have in the same space as a dehumidifier? I'm not planting flowers, storing vintage guitars or anything like that in there or anything, but anything that one might keep in a garage that doesn't want a dry environment?
My garage is simple....tools, parts, cars, fridge, the usual stuff one would keep in their garage.......

 

[Major Ramifications]

Have to say that I'm not too pleased with the Kenmore dehumidifier I bought a couple years ago. It was on sale and I had been using one I had for fifteen years - figured a new one may consume less energy.

Two years later the fan wasn't running this spring. Opened it up and found that whereas the old one had your basic switches for the fan and a humidistat, the new one includes a wonderful PC board of gizmos... Guess what seems to be bad (tested all the other components)? Guess what is no longer available as a repair part? Going to have to drag the old one out and start using it again - never did get around to throwing it away...

I can send you another board for free, if you pay for the shipping.

 

[The Hot Rod Grille]

I recently purchased a DeLongie 50 pint model to control humidity in my 1350 sq. ft. garage. The garage has a 3-ton heat pump for heating/cooling and with the dehumidifier I am able to keep the garge at 72 degrees and 40% humidity during the hot and humid summer days in West Virginia. The unit features a built-in pump that allows you to run the 16 foot hose (included) to a drain or even up 16 feet to a window if used in a basement. The unit has UL Energy Star rating for efficient operation. I purchased it NIB for $220 delivered from an eBay seller. It was delivered within two days by FedEx Ground. My only regret was that I didn't buy it sooner!

Jim Winter
The Hot Rod Grille Garage

www.wvpinball.com

 

[Roospike]

I recently purchased a DeLongie 50 pint model to control humidity in my 1350 sq. ft. garage. The garage has a 3-ton heat pump for heating/cooling and with the dehumidifier I am able to keep the garge at 72 degrees and 40% humidity during the hot and humid summer days in West Virginia. The unit features a built-in pump that allows you to run the 16 foot hose (included) to a drain or even up 16 feet to a window if used in a basement. The unit has UL Energy Star rating for efficient operation. I purchased it NIB for $220 delivered from an eBay seller. It was delivered within two days by FedEx Ground. My only regret was that I didn't buy it sooner!

Jim Winter
The Hot Rod Grille Garage

www.wvpinball.com

WOW a 3 ton unit for only 1350 sf !?!? no wonder you have a humidity problem and need a dehumidifier.

1 ton = 1,200 sf average

Sounds like you way oversized your unit and it dont run long enough as it should to take out the humitity .

 

[The Hot Rod Grille]

WOW a 3 ton unit for only 1350 sf !?!? no wonder you have a humidity problem and need a dehumidifier.

1 ton = 1,200 sf average

Sounds like you way oversized your unit and it dont run long enough as it should to take out the humitity .

I had it designed and installed by a local firm with a good reputation. I have 12 foot ceilings (for the 4-post lift). The air handler is in the attic with 12 "drops" to distribute the air. 6 inch insulated walls and insulated garage and entry doors. I keep the garage roughly the same temp year-round, so the 3-ton unit comes in handy when it gets near zero in January. By using the dehumidifier, I can keep the garage at 72 degrees rather than 68 to feel comfortable. It cost less to run the dehumidifier than the heat pump!

Jim Winter
The Hot Rod Grille Garage

www.wvpinball.com

 

[Major Ramifications]

WOW a 3 ton unit for only 1350 sf !?!? no wonder you have a humidity problem and need a dehumidifier.

1 ton = 1,200 sf average

Sounds like you way oversized your unit and it dont run long enough as it should to take out the humitity .

Roospike,
I don't know what things are like in the Mid West, but every A/C guy I have talked to in this swampy climate suggests about 1 ton for every 400 square feet. Given my experience with my own houses, they are pretty close.

 

[Roospike]

Yep , it gets hot and humid here in Nebraska too. I'm sure not as much as the south.

I lived in North Carolina and it was very humid there and with the proper sized central A/C unit we kept the home and shop at around 40-45% humitity.

If you oversize an central or an A/C unit you will end up with cool humid air just like The Hot Rod Grille and you will need a dehumidifier to make up the difference.

The whole idea of an A/C is to run long enough to take out the moisture , over sized and it dont run long enough to do so and you end up with 60-70% humidity and cool air.

I agree that places down south will very with % but it shouldnt be as much as 40% difference.

The rule of thumb is 1 ton = 1,200 btu for best case and 1 ton = 600 sf worst case and worst case is old leaky , uninsulated or poor insulated , drafty , lots of sunny side windows , no shade ect.....ect....

I have NEVER heard of 1 ton = only 400 sf.

Your average garage/shop being what it is will average 850 sq per 1 ton of A/C unless you have a barn.

 

[Major Ramifications]

I can assure you that one ton per 600 square feet is inadequate even in a fairly modern insulated house in this area. Our house is right at this number and the unit runs CONSTANTLY in the summer, and it can't maintain a comfortable temperature on the really bad days.
Also, 40-45% indoor humidity is only a dream around here. There is just too much water in the air to start with. Every time we open the door, the humidity hits us like a load of bricks. I get all wet with sweat just going to get the mail out of the mailbox. This is one of the main reasons my family and I are going to move.

 

[Kevin54]

Even when I open the door for the afternoon, it will dry out the air after I close the door. The only problem I have it the garage is noticeably hotter than the house is. The dehumidifier raises the temp of the 2 car garage.

A dehumidifier should lower the temp of the garage. By taking the humidity out there is nothing to carry the heat. A humidifier will raise the temperature and that is what you want in the winter and a dehumidfier in the summer. One thing that really helps is that if you have windows is to keep blinds up and keep them shut in the day. My garage is probably 15 degrees cooler than the outside temp in the heat of the day and there is no shade around it. Good insulation is also a must.

Kevin

 

[Roospike]

I can assure you that one ton per 600 square feet is inadequate even in a fairly modern insulated house in this area. Our house is right at this number and the unit runs CONSTANTLY in the summer, and it can't maintain a comfortable temperature on the really bad days.
Also, 40-45% indoor humidity is only a dream around here. There is just too much water in the air to start with. Every time we open the door, the humidity hits us like a load of bricks. I get all wet with sweat just going to get the mail out of the mailbox. This is one of the main reasons my family and I are going to move.

These #'s are rule of thumb and averages , there are a lot of things that can come into play.

How old is your unit , how well insulated is your house , how clean is your unit , is it checked yearly ? ect .....

I have seen many homes in Florida with NO INSULATION in the walls and these were modern houses less then 10 years old. and very little in the attic.

 

[Major Ramifications]

Our house is not too old, has insulation in the walls and plenty in the attic, and not a lot of windows. But I am not just talking about this house. Every house I have ever lived in has needed WAY more BTU's than what you are claiming.

 

[Roospike]

Our house is not too old, has insulation in the walls and plenty in the attic, and not a lot of windows. But I am not just talking about this house. Every house I have ever lived in has needed WAY more BTU's than what you are claiming.

Odd ...........Dont know brother.

Every house i have owned ends up about 1000 sq per ton and in house humidity has always been low even when we lived in the south.

These are not my #'s , its an industry standard.

tell your kids to keep the damb door shut.

 

[Major Ramifications]

They do OK with closing the door, but I am still having a problem trying to get them to completely shut off the bathtub faucets when they are finished using them. They let the hot water dribble all night.

But about the BTU thing, all I am saying is don't jump on the guy about his unit being too large, because not every place is like the Mid West. We don't just live in the South, but in the Gulf South. We are practically in the Gulf of Mexico. The heat and expecially the humidity down here are just stupid. That is why every A/C guy I have talked with says we need a much larger system (we have 3.5 tons, they say we need 5).
Anyway, we have interrupted this guy's thread enough. I am happy to agree that we disagree on this issue.

 

[Roospike]

********** *************

 

[jmiller]

Here is my situation that I need help with, I'm getting mold in the garage. It's not a typical garage so here are some photos to help explain.

Normal part, 24 x 30 concrete block, no insulation, 3 small windows on opposite walls.

Now the not so normal part, as you can see from the pics it has a full basement under it. Ceilings are a 10 1/2" concrete slab, walls are only 7', no windows, one 5' walk-in door, no insulation, no heat with a small 110 window unit a/c.

It stays about 10 deg cooler in the summer and 10 deg warmer in the winter than the ouside temp.

The upstairs part of the garage isn't as bad, but the lower is starting to get that musty smell and I've noticed mold on some of the scrap wood and vinyl car seats that I have down there. I went down there last night and the air just felt "sticky". I'm guessing a dehumidifier will help with my problem, but I don't know what size to get or if I need one on each floor?

I live in central KY and today it's 91 deg & 72% humidity, yesterday was more typical of mid-summer weather in this area, 96 deg & 85% humidity.

Any suggestions?

 

[jm1fd]

Any suggestions?

Can you circulate some air between the two levels, and run the window unit? That could very well take care of your problem because the A/C unit will dehumidify as it cools.

Your other options would be to put in a fan to circulate some outside air into the space, or to get a dehumidifier.

 

[JMURiz]

Cool garage! I'd suggest getting some kind of dehumidifier in there, also maybe some type of UGL Drylock paint on the concrete walls might help keep some of that moisture from seeping through (an expert might have a better POV on this).

I'd also think about some type of air circulation down there, either via vents or fans.

 

[MAINIAC]

be prepared for a big increase in your electric bill. I would run one all summer here in NH but at $25 a month over the already huge electric bill I only do the small basement where we store clothes and books.

 

[jmiller]

Thanks for all the replies. The only air circulation I can get is by opening the garage door up top and the walk-in door below which doesn't help hardly any at all. As far as running the window a/c unit I have no problem doing that but will a dehumidifier be a better solution?
I just recently had 8 - 4 bulb 4' flourescent lights added, my 60 gal compressor hooked up and my new welder running a lot so my electricity bill is already high, but I have way to much money invested in cars and tools to worry to much about it now.

 

[Steve in Mi]

Nobody has mentioned rock salt dehumidifying, why? You can't get a cheaper solution to knock down the humidity and keep rust to a minimum. Okay I'm not in the South but we have humid weather here in Michigan just not to the same degree. My attached 24 X 36 shop (some would call it a garage but a garage is where cars are kept, right, and none have been allowed in this structure since 1978) is concrete block and brick that stays cooler than the outside air in the Summer. The only insulation is above the ceiling. Plus there is some big iron (milling machines, lathes, bandsaws, planers etc.) in this space I can't afford to let rust. Because I'm not contending with cars going in and out I use the man door off the breezeway most of the time and only open the overhead doors when it is absolutely necessary. I use rock salt dryers (5 originally, now 3 because it is used less often) to pull the water out of the air and keep my machines and tooling from turning red.

My detached 28 X 48 two story shop is well insulated and with a moisture barrier is much easier to keep dry. Again I don't open it up any more than necessary. My highest inside temperature (no A/C) has been 72 for the past several years and I usually only see a week or two of that in late July/early Aug. (I keep the thermostat set at 63-64 throughout the heating season). Anyway, about 5 years ago I bought a new dehumidifier to replace an old unit in my basement and first tried it in my detached shop. In mid July I didn't get but a quart of water after running it on high for a week straight. There is only one rock salt bag and bucket in this shop and I have never had to empty it since building this shop in 1981.

 

[jmiller]

Here is what I have done so far. I bought a digital Hygometer ($25 delivered)to get some accurate measurements of what I would be dealing with. It has a feature that will give you the minimum/maximum humidity level between the times that you manually reset it. I left it in place for 7 days and during that period the level was between 71% - 86%, no wonder I was having a mold problem.
After much research I purchased a Danby model DDR606 dehumidifier ($218 delivered) and hooked it up this morning with a continuous drain line to outside of the building. I started it a 11:00 am this morning and the readings were 73% humidity & 81 degrees, as of a few minutes ago it was at 56% humidity & 85 degrees.
The difference in the air quality is amazing. I wish I would have done this sooner.

 

[Steve in Mi]

Whatever works!

I've not measured the actual humidity in my shop or garage so I can't quote any numbers. I do know that 2 bags of rock salt for a 30 year period to keep my precision machines from rusting is way less $$$ than [$25.00 + $218.00 + electricity to run fans and a dehumidifier].

 

[jmiller]

In mid July I didn't get but a quart of water after running it on high for a week straight.

To give you an idea of the difference I got a little over 1 quart while I was drilling a hole in the concrete block and mounting the drain line (about 1 hr).
I would have been happy to buy a couple of bags of rock salt but in my case I don't think it would have been enough.

I'l update next month when I get my electric bill.

 

[Steve in Mi]

I would have been happy to buy a couple of bags of rock salt but in my case I don't think it would have been enough.

But then you really don't have a clue until you try it, do you.

Did it go right over your head that the quart of water collected on the highest setting was with one rock salt dryer in that shop, what I had already concluded was sufficient. That structure is completely wrapped in 6 mil poly so the only moisture that gets in it is from an open door, window or my breath. The first two I keep closed as much as possible and I don't hold my breath. So your shop is wetter - use more dryers. Or don't. Rant mode off!

 

[SteveU]

What size bag of salt are you using & what are you using to hang it with? Are you using the real large coarse stuff for water softeners or finer stuff like for melting ice in the winter? I bought some of the dehumidification pellets for the basement & they seemed to work, filled the jars I had them in with water but that stuff is pretty expensive for the amount you get.

 

[HacksawsGarage]

interesting. i have always experienced a pitting and powdery white "rust" on my aluminum motorcycle engines. i have a detatched garage. the problem seems to be fall and spring prevelant. this being because i get condensation forming as a result if day/nite tempreture extremes. i wonder if a dehumidifier would help.

 

[Steve in Mi]

What size bag of salt are you using & what are you using to hang it with? Are you using the real large coarse stuff for water softeners or finer stuff like for melting ice in the winter? I bought some of the dehumidification pellets for the basement & they seemed to work, filled the jars I had them in with water but that stuff is pretty expensive for the amount you get.

There is information on the web about the process if you search words like "salt dehumidifier", "Rock Salt" etc., etc..

Here are a couple that I picked out where the first link carries a warning about the corrosive nature of salt (an important consideration in setting up your system);

http://discount-air-fan.wowshopper.com/htm-pages/how-does-dehumidifier-work.htm

Homemade Dehumidifier

Some inventive people use bags of road de-icing salt to absorb moisture from the air. The wet salt solution drips into a pan or floor drain, drying the air. Because the salt runs off with the water removed from the air, it must be replaced.The system has no moving parts. If you try this homemade dehumidifier, remember that salt is highly corrosive to metals and quite hard on the skin.

If measuring the humidity is important to you then there are some tips here including calibrating your Hygrometer.

http://www.cmhc-schl.gc.ca/en/co/maho/yohoyohe/momo/momo_002.cfm

Okay, your questions.
The salt I use is plain NaCl rock salt common for use in snow and ice melting. The same material the salt trucks spread/dump on our Michigan roads to 'make driving safer' and rust out our cars. It ranges in size from fines to crystals maybe a 1/2" with most of it in the ~1/4" size.

Start out small and make improvements to your setup as you see the need. A 20 pound bag of rock salt is enough to make at least 2 dryers. Dryer is my term for a breathable bag of salt and a plastic bucket/pail. Let me define "breathable bag" as a woven plastic bag that easily allows air and the salt to come into contact while still containing the salt. Put 5 - 10 pounds of rock salt into the bag and tie it using plastic rope from the dollar store. Initially I hung these bags from screw eyes in the ceiling of my garage and placed a 5 gallon plastic pail below to catch the water that collects on the bag and drips into the bucket. I tried a few different arrangements sometimes hanging the bucket directly below the bag and still above my head to avoid a pail getting moved where it didn't catch the water, one hanging directly over a floor drain (a non rusting type drain), and evolved to where I set the salt bag on wood chunks of 4X4 right in the plastic pails. Depending on how much water you are removing one of these methods should get you started. Some of the plastic pails are semitransparent and allow you to see the water level in the pail so you will know when to dump it. That's about it. FLASH warning again about the corrosive nature of salt - keep it away (2 -3 feet) from the metal you are protecting and last, while you may want to add a fan to circulate air to speed transfer up - DON'T, it isn't necessary, the water in the air will find your salt weither it is in a bag or the undercarriage of your car. As the air dries, fine crystalized salt appears on the outside of the bag, a fan may cause that to become airborn - this would not be good in my opinion.

Edit; devise a plan for dumping the salt water - probably not on your lush green grass.

 

[JMURiz]

Here is what I have done so far. I bought a digital Hygometer ($25 delivered)to get some accurate measurements of what I would be dealing with. It has a feature that will give you the minimum/maximum humidity level between the times that you manually reset it. I left it in place for 7 days and during that period the level was between 71% - 86%, no wonder I was having a mold problem.
After much research I purchased a Danby model DDR606 dehumidifier ($218 delivered) and hooked it up this morning with a continuous drain line to outside of the building. I started it a 11:00 am this morning and the readings were 73% humidity & 81 degrees, as of a few minutes ago it was at 56% humidity & 85 degrees.
The difference in the air quality is amazing. I wish I would have done this sooner.

Awesome, that's quite a change in humidity, best of luck, hopefully this will solve your issues.