Dehumidifier for the laundry, furnace room

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CountryBoy
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Dehumidifier for the laundry, furnace room

Post by CountryBoy »

I have a laundry / boiler room:
15 ft. long
10 ft wide
10 ft. high
with a permanent opening in the cinder block to vent to the outside.

The humidity is a serious problem to the floor and surrounding wood during these humid days.

I have searched the Boglehead suggestions and am wondering if anyone has recent thoughts on this.

We are talking serious humidity coming from the well storage tank and pipes and the hot water storage and the furnace pipes.

Thanks.

cb.
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Epsilon Delta
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Re: Dehumidifier for the laundry, furnace room

Post by Epsilon Delta »

You might want to consider a heat pump water heater. You probably don't want to replace a functioning water heater, but if you do the research when it comes time to replace you're ready to make the change if appropriate.
CountryBoy wrote: We are talking serious humidity coming from the well storage tank and pipes and the hot water storage and the furnace pipes.
All of these should be closed systems. If they are a source of humidity you have a leak. Condensation dripping from cold water pipes and tanks is a symptom of humidity, not a source. You want to find out where the water is coming from.
jebmke
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Re: Dehumidifier for the laundry, furnace room

Post by jebmke »

Epsilon Delta wrote:Condensation dripping from cold water pipes and tanks is a symptom of humidity, not a source. You want to find out where the water is coming from.
This. It is likely either airborne or coming in through a basement floor/walls.

We had a lot of humidity in our crawlspace. We had a vapor barrier installed and sealed off the vents to the crawlspace. That and some low cost re-routing of downspout water solved the problem.
When you discover that you are riding a dead horse, the best strategy is to dismount.
fishboat
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Re: Dehumidifier for the laundry, furnace room

Post by fishboat »

Here in the midwest with having full basements, a dehumidifier is pretty much standard equipment. 50, 60, 70 pint units are readily available. They cost a few bucks /month ($10-$15??..haven't checked it in years) to run, but there isn't much choice to do otherwise. Mine pulls a gallon or two of water every couple days out of the air this time of year.
Last edited by fishboat on Fri Jun 26, 2015 6:41 am, edited 2 times in total.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

The pipes of the well tank and the hot water tank have very considerable condensation.

The condensation is the source of my problem.
jebmke
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Re: Dehumidifier for the laundry, furnace room

Post by jebmke »

The condensation is water coming out of the air. Where did it come from? What is the original source putting water into the air?

A dehumidifier may be the answer but until you know where the moisture is coming from you can't be sure it is the best answer.
When you discover that you are riding a dead horse, the best strategy is to dismount.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

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Today in NY we have over 80% humidity.

My furnace room has a whole about 14" x 8" through the cinder block for the purpose of venting to the outside. My guess is that is is a good thing.

Any dehumidifier would obviously be dehumidifying the air that comes through that vent as well as the entire room. For some reason I always thought that it was good to have that vent. Isn't it?
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

jebmke
a vapor barrier installed and sealed off the vents
What kind of vapor barrier is that? Don't I still want free flow of air?
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Epsilon Delta
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Re: Dehumidifier for the laundry, furnace room

Post by Epsilon Delta »

CountryBoy wrote:The pipes of the well tank and the hot water tank have very considerable condensation.

The condensation is the source of my problem.
You can prevent the condensation by insulating the cold water pipes. You want the insulation to be waterproof and airtight so that it keeps the warm, humid air in the room away from the cold pipes. You can get R1 foam and foil tape which you spiral round the pipe or you can use the foam tubes usually used on hot water pipes, just make sure you tape the seams. Do not use fiber glass or open cell foam, which can get wet and messy. Insulation will not reduce the humidity, but it will stop water condensing and dripping on the floor. Insulating a tank is more difficult, you may be able to build an airtight box using Styrofoam boards and glue, or maybe a thin layer of spray foam.

Now a crazy idea: You could run the incoming cold well water through a heat exchange that captures condensation and drain it safely. This would reduce the humidity in the space and warm up your cold water, reducing water heating costs and preventing your toilet tank from sweating.
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Epsilon Delta
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Re: Dehumidifier for the laundry, furnace room

Post by Epsilon Delta »

CountryBoy wrote:Today in NY we have over 80% humidity.

My furnace room has a whole about 14" x 8" through the cinder block for the purpose of venting to the outside. My guess is that is is a good thing.

Any dehumidifier would obviously be dehumidifying the air that comes through that vent as well as the entire room. For some reason I always thought that it was good to have that vent. Isn't it?
Pretty much right on all points.

One thing about that vent. You said there is a boiler (and maybe a water heater) in that room. These need a source of air for combustion. Modern boilers may have two PVC pipes to the outside, one is the exhaust, the other draws air from the outside to feed the flame. Older boilers (and some modern ones) draw combustion air directly from the room, and indirectly from any vents in the room. So that's probably why the vent is there and you don't want to block it if it's still serving that function.
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Rainier
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Re: Dehumidifier for the laundry, furnace room

Post by Rainier »

CountryBoy wrote:Today in NY we have over 80% humidity.

My furnace room has a whole about 14" x 8" through the cinder block for the purpose of venting to the outside. My guess is that is is a good thing.

Any dehumidifier would obviously be dehumidifying the air that comes through that vent as well as the entire room. For some reason I always thought that it was good to have that vent. Isn't it?
Don't ever talk about relative humidity, it is useless as a measure of water in the atmosphere.

I would close the vents, it is an endless source of moisture. You are never going to dehumidify the entire atmosphere, so stop letting it in.

Most vents were designed to let in air to feed a furnace or water heater, many newer systems do not need this.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

I already have "the foam tubes" around the pipes on the cold water as well as the hot water.

I guess I am trying.
fishboat
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Re: Dehumidifier for the laundry, furnace room

Post by fishboat »

Sweating pipes is a symptom..not the problem. You can insulate them to prevent condensation, but you still have very high humidity in the room..which can be a source of mold/mildew...

Make sure your equipment (furnace, hot water heater) is vented appropriately (exhaust and combustion air), seal up any other venting to the outside, and buy-use a dehumidifier. Also make sure any outside water (gutters, sump pump outflow...) is piped away from the basement to reduce moisture next to the concrete. There's really nothing mysterious about this..I've been running a dehumidifier in my basement for 30 years. My dad ran dehumidifiers in the basement 50 years ago..nothing new here..
nordlead
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Re: Dehumidifier for the laundry, furnace room

Post by nordlead »

Seal the vents in the basement and buy a dehumidifier. If any appliances need venting from outside, do that directly rather than venting the entire basement. Basically, the same thing others said.

One thing to add, is you can paint the cinder blocks with drylok (or equivalent), which will reduce moisture leaking through.
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Re: Dehumidifier for the laundry, furnace room

Post by jebmke »

CountryBoy wrote:jebmke
a vapor barrier installed and sealed off the vents
What kind of vapor barrier is that? Don't I still want free flow of air?
I have a crawl space, not a basement.

With that in mind, the vapor barrier is a sheet of heavy duty mylar. It keeps moisture from the ground from rising up into the crawl space.

The vents are closed to prevent the warmer air from outside (which is laden with water) from entering into the cooler crawl space where it would condense. While our crawl space is not perfectly sealed, the combination of the vapor barrier and the closing of the vents (and redirecting downspouts and doing some grading outside the foundation) has kept the moisture level down enough such that any that creeps up into the house is easily handled by the A/C system.

Even if you decide/need to add active dehumidification you need to seal the space as much as you can to prevent ingress of water. Warm air can hold a lot of water.
When you discover that you are riding a dead horse, the best strategy is to dismount.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

Could people tell me what KIND of vapor barrier to use?

Thanks.
Globalviewer58
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Re: Dehumidifier for the laundry, furnace room

Post by Globalviewer58 »

Country Boy:

The vapor barrier can be a 6 mil (thickness) sheet of plastic film. Here's a How To video on vapor barrier installation in a crawl space: http://www.familyhandyman.com/smart-hom ... e/view-all
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

Many thanks.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

I was talking with a salesman at Home Depot and he suggested I get one of these units.

http://www.wavehomesolutions.com/ventilation/landing/

Does anyone out there have experience with it?

Thanks.
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walkabout
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Re: Dehumidifier for the laundry, furnace room

Post by walkabout »

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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

Wow, that was one comprehensive response.
Thanks.
fishboat
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Re: Dehumidifier for the laundry, furnace room

Post by fishboat »

CountryBoy wrote:I was talking with a salesman at Home Depot and he suggested I get one of these units.

http://www.wavehomesolutions.com/ventilation/landing/

Does anyone out there have experience with it?

Thanks.
Lots of slick marketing..slick video..lots of slick. How would you know if it actually works(with respect to the evil black cloud that it expels)? What do you do if the pipes continue to sweat(they will)? Get a refund?

Pulling air down the stairs looks impressive..but in practice it won't be nearly that clean, nor effective. If the house AC is off and the wave-thing does manage to pull air down from the upper levels..that air will have high humidity also..the only reason you have sweaty pipes downstairs is because the temp is lower downstairs. (here's an experiment..take a glass of water in your main-level kitchen in the summertime and drop a few ice cubes in it...does the glass form some condensation on the outside? why is that?) With the wave-thingy you'll be pulling a vacuum on the basement (as this machine is expelling air to the outside). Do you run gas-fired appliances in the basement? Gas fired appliances require a flue for exhaust gases...particularly a water heater with the open-cap flue. Pulling even a slight vacuum on the basement can reverse the flow of those exhaust gases into your basement. When the wave-thingy runs, the slight vacuum it's pulling will be satisfied with 'basement-external' air from the path of least resistance. Pulling air down from upstairs isn't easy..if the wave unit can pull air from any other source with less resistance, it'll do so (flue vents, furnace makeup air from outside, poorly sealed areas around the foundation..windows...etc).

The wave site says a dehumidifier costs $60-$90/month...nonsense. That's my entire house electric bill in the summer(ex AC)...and I run a 70 pint DH unit.

I think you're thinking too hard...not that there's anything wrong with that. Make sure outside water flows away from your foundation, buy a 50 or 70 pint DH unit, plug it in, and move on. Curing your issue is really very simple.
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CountryBoy
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Re: Dehumidifier for the laundry, furnace room

Post by CountryBoy »

You are probably right.
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