Basement Dehumidifier

[N80]

I live in a 90 year old house. It has a walk in basement that is basically just concrete floors but otherwise unfinished. It is damp and occasionally with heavy rains there is water on the floor. There is very little way to solve this problem completely. I could have it dug out all around the foundation on the front and seal the foundation walls but that would be very expensive and even that would not solve the problem as sometimes (very rarely) water oozes up through the concrete floor. This is a fairly common problem for all the homes on our street. I've done some patching on the interior basement walls and it helps a little.

Ventilation is okay.

My shop is down there and as it is sometimes my tools get a thin skim of rust on them and sometimes soft materials will get some mildew. Oddly, the floor joists and subfloor stay dry as a chip.

Anyway, I'm considering getting a high capacity dehumidifier just to keep the general humidity down most of the time. I'm wondering if anyone has experience with these and/or recommendations. The square footage is probably close to 1000. Maybe less.

There is a drain but it was for a washing machine that was down there years ago and is above floor level so I will need to have a condensate pump to push the water up to the drain if the dehumidifier does not have a pump.

Thanks for any advice, price ranges, pitfalls, etc.

 

[dstig1]

So mount the dehumidifier up higher so it can drain directly... That will also protect it from any standing water. I got the Innovative Dehumdifier from Supplyhouse.com and I am not terribly impressed. It does not seem to pull out as much water as the portable unit I had before, but I think some of the other ones on this site might work better. Supplyhouse is awesome to deal with.
Dehumidifiers - Honeywell Dehumidifers - House Dehumidifiers - TrueDRY Dehumidifiers - Honeywell TrueDRY - SupplyHouse.com

 

[dlctcg]

If the basement is just concrete & does not have any coatings or finishes on it.... you have options. We deal with this all the time here in New England & we have to resolve this problem for many clients prior to finishing a basement. I would look in to a product called Sani-Tred to completely seal the basement, if done correctly I'm confident you can resolve your problem with out the need of a high capacity dehumidifier. We have used the product for 12+ years with outstanding results on both poured concrete floors & walls & also block foundations. Prep & application are everything. I would check them out & if you have any question on product prep or application let me know, I'll see if I can answer them. (I have no affiliation with them but have been istalling it for 12+yrs on our projects... it just works)... The nice thing is you can apply it in sections if need be due to space restrictions & it is something you can apply yourself... It is pretty simple if you follow the steps correctly.

DIY Waterproofing Products | Liquid Rubber Coating | SANI-TRED(R)

If you decide to go the dehumidifier route there are only two brands we recommend for large capacity units... these companies only do air quality & air control; they are not HVAC equipment companies.

Santa-Fe / Ultra-Aire is one: Dehumidifiers Archives - Santa Fe

Aprilaire is the other: A Whole-Home Dehumidifier from Aprilaire

But in my opinion I would look at Sani-Tred first...

 

[RalphVa]

Just a fan is often enough or fans on timers. That's what we have in the basement of the carriage house and the pool equipment area. In the house utility room, we have both fans and a dehumidifier.

Ralph

 

[JamesHW]

We are running a dehumidifier in our old house (rubble foundation and only a partial cement floor and it has done very well). Condensate is pumped outside with an attached hose and built-in pump (no drain).

We have been planning on replacing our old electric hot water heater and discovered new models that include a heat pump that while drawing heat from surrounding air have the knock-on effect of dehumidifying the basement, so are looking at that as an option.

 

[Industrial Toys]

Just thought I might mention this. I have a problematic dehumidifier in the fruit cellar that has been giving me trouble. Fifty years old (quality) but the bearings always give out in the fan motors. Tried lubricating it once already and that lasted for a while.

Anyway, fruit cellar very damp, weekend project. Cut wire to (seized) blower motor and tye rap a 12" or so high quality (high volume) computer fan to the grill. SEEMED to work GREAT!

Next morning, not a drop more water in the bucket!

SEEMS that too much air flow just evaporates the air back into the room! Now on the hunt for a smaller computer fan! Original fans of the size are stupid expensive.

I either add the soft water to my laundry or save it for batteries.

 

[old and tired]

So it bugs me that some of the links mention above doesn't list prices. If you have to ask how much, I can't afford it!!

I run a cheap (relatively $170?) dehumidifier from Lowes Home Improvement, Hisense, they last just shy of 3 years?? Got several dead ones over the years. I have it setup on top of the dryer and it drains into the washing machine's drain. Pretty sure the city doesn't like that... It's in the "shop area" of the basement.

I got tons of spare parts if something other than it just quits working pops up!

 

[CalG]

I read some time ago that the Japanese have the edge on producing dehumidifiers. Based on my experience with a Toshiba unit, I might agree.

We have a damp walk out basement in the summer months. (no trouble in winter with the wood stove down there ;-) I keep a mill and a lathe there, and I don't like rust!

We had an Emerson unit for over 20 years, but it died about 5 years ago. I did some reading. Choose the Toshiba unit based on size, features and PRICE! It was just set up last week again when we had some warm and muggy days. PERFECT!

I run the controls at 65% RH, and that seems to be a good (rust safe) setting. At 50% RH, the unit never shuts down, $$$$. At 70% I see rust films on clean bare steel.

I have the unit on the floor, against the outside wall (between the mill and the lathe) A hole was drilled through the wall to snug fit on a garden hose that gravity drains to daylight about 4 feet from the foundation .

The waste heat from the dehumidifier is welcome here in VT . The ground never gets above 55, so the floor and walls stay cool.

Hence the high humidity ;-)

Note, Our electric bill pretty much follows the outside air temperature. Biggest bills in the humid months of Summer. I'm not sure how anyone can save money getting water out of air....

 

[Industrial Toys]

I would buy any fifty year old wood grain, steel housed dehumidifier on sight. No interest in the five or ten year plastic junk, with unecessary computers, electronics, remote controls and so forth.

 

[CADplans]

The actual air temperature is important to most dehumidifiers,,
I have two,, both will work perfectly from May 'til September,,
after September, the basement is too cold for the dehumidifier to work,,,

SO,, it the basement is cold, and damp,, you might have to add a little heat to get the dehumidifier to remove moisture,,,

 

[CADplans]

I would buy any fifty year old wood grain, steel housed dehumidifier on sight. No interest in the five or ten year plastic junk, with unecessary computers, electronics, remote controls and so forth.

My older dehumidifier was purchased used in 1979,, and still works perfectly. I think I paid $10 for it at a yard sale.
It was replaced because the plastic drip tray became old and cracked,, I made a new tray out of stainless steel.
No telling how old that thing is,, but, it works great,,,

If I blow a 12 inch desk fan at the dehumidifier,, it will double the amount of water it takes out of the air,,,

 

[zzvyb6]

Do you have whole house air conditioning ? What can help is to install switchable ducting to suck the (damp) air out of the basement. This works for the hot months. In the winter, a regular dehumidifier ought to slove the problem. As mentioned, add some heat (wood burners pump lots of air out of the house and often result in a dry area.

In my place, it takes a while to pull all the humidity out of the surrounding basement floor, walls, structure, etc. If you have a laundry down there, seal it off or move it upstairs. You also need to keep the access to the basement closed. As warm, humid air cools, it sinks and water vapor condenses on to surfaces.

Check your gutters, too. A lot of moisture comes in thru short gutter downspout runs. Longer runs away from the house and steeper grading to get better runoff.

 

[N80]

To answer some questions: Regarding price I have been looking at units from Honeywell and Aprilaire all in the $1000 price range. Reviews suggest that they work great while they work but it seems a lot of folks get no more than about 3 years out of them. The Aprilaire units have a 5 year warranty but only if professionally installed. The problem with that, in my opinion, is that installation pretty much involves plugging it in. Paying a pro to do that is idiotic.

dstig1, good thought mounting the unit up high and letting it gravity feed into the old washing machine drain. That will be easy.


dlctg, I have thought about coating the interior of the basement many times but every time I research it something puts me off. I'm assuming that even just the materials are expensive even if I do it myself. I would only really need to do the front half of the basement since that is the only part where the water seeps in. I get some water under the 'garage' door on the back side but that is a gutter problem not a seepage problem. I did go to the link you provided and I am curious now. Wondering about price though. However, even if I do this I still think a dehumidifier would be useful so I may end up doing both since the relative humidity is really high here in the summers anyway.

zzbyb6, that is an interesting thought. The ducting in the basement is nearly as old as the house. Round and square galvanized. On two of the cold air returns coming down from the first floor there are open vents that have been covered up with cardboard for my entire life. I bet if I remove that cardboard then basement air will be drawn into the HVAC unit (which is in the basement) and help dry the air. I may give that a try.

In regard to a dehumidifier not running in the winter months that will probably not be an issue. It is generally drier here in the winter plus with that ancient leaky ductwork and no insulation in the first floor subfloor the basement stays reasonably warm.

 

[kenmac]

just my 2 cents. I wouldn't return basement air into my A/C system from a basement, and have the A/C system blow this basement air into my living space.

I too have issued with water seeping through my concrete floor.
My A/C unit (ah) is installed in that basement area. There's no way I would pipe return air from my basement and circulate it in my home.

I intend to remove everything from my basement, pressure wash the concrete floor and try one of the commercial epoxy sealers to hopefully prevent water from seeping up through the concrete.
Until then. I will run my cheap HD dehumidifier

 

[dlctcg]

just my 2 cents. I wouldn't return basement air into my A/C system from a basement, and have the A/C system blow this basement air into my living space.

I too have issued with water seeping through my concrete floor.
My A/C unit (ah) is installed in that basement area. There's no way I would pipe return air from my basement and circulate it in my home.

I intend to remove everything from my basement, pressure wash the concrete floor and try one of the commercial epoxy sealers to hopefully prevent water from seeping up through the concrete.
Until then. I will run my cheap HD dehumidifier

If your basement is already bare concrete you can pressure wash it... but more importantly you should acid etch the floor & then neutralize it prior to putting any coating in it.... I again will recommend you look at Sani-Tred... this is a product that has worked over & over for us on projects....

 

[lennyzx11]

Do you have whole house air conditioning ? What can help is to install switchable ducting to suck the (damp) air out of the basement. This works for the hot months. In the winter, a regular dehumidifier ought to slove the problem. As mentioned, add some heat (wood burners pump lots of air out of the house and often result in a dry area.

In my place, it takes a while to pull all the humidity out of the surrounding basement floor, walls, structure, etc. If you have a laundry down there, seal it off or move it upstairs. You also need to keep the access to the basement closed. As warm, humid air cools, it sinks and water vapor condenses on to surfaces.

Check your gutters, too. A lot of moisture comes in thru short gutter downspout runs. Longer runs away from the house and steeper grading to get better runoff.

Another one in Vermont.
100 years old stone and concrete huge basement. It used to fill up about 6 inches with rain water when I first got it.
I run a GE dehumidifier at 60%. Largest one they had at Home Depot. Sets on a small table next to the sump and gravity drains into the sump cistern. The table keeps it above any possible flood zone.

The absolute best thing I did was to add gutter extensions and repair the leaking gutters to take the water away from the foundation.
It stays dry now, even with a high water table.

 

[mikester]

If you have an old electric water heater consider buying a Heat Pump Water Heater. You get all the benefits of the dehumidifier plus the waste heat goes into heating your water.

 

[KennyG]

I think the basement humidity issues are very specific to the location and house. I have a large house with a walk-out basement. When I bought it we had water running down the basement walls in humid weather. I installed an air to air HX ventilator to pull air from the basement and bring outside air into the first floor. I added air returns in the basement ceiling to increase the A/C dehumidification (but we only run A/C 10 to 15 days a year) and to provide circulation in the winter when we run a wood stove in the basement. Finally, I added a dehumidifier in the basement that is drained to the sump pumps. It's one I got was a hOmeLabs from Amazon : Amazon.com - hOmeLabs 3, Sq. Ft Energy Star Dehumidifier for Large Rooms and Basements - Efficiently Removes Moisture to Reduce Likelihood of Mold and Mildew -. It's been working fine for about 9 years now.

Besides a dehumidifier, I think you should try to maximize air circulation.

 

[fruitcakesa]

If you have an old electric water heater consider buying a Heat Pump Water Heater. You get all the benefits of the dehumidifier plus the waste heat goes into heating your water.

X2 on this

 

[kenmac]

If your basement is already bare concrete you can pressure wash it... but more importantly you should acid etch the floor & then neutralize it prior to putting any coating in it.... I again will recommend you look at Sani-Tred... this is a product that has worked over & over for us on projects....

I will look into that product. I know I need to PW the area and know it needs attention.I just have to get around to doing it.

I would never pipe return air from a humid basement (that is not being used as a den, etc,) into my HVAC system, and have that air circulated throughout the living space.
You could end up with some very Bad air quality for your living space