Author Topic: Humid basement issue and INSANE dehumidifier cost  (Read 17579 times)

merula

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Humid basement issue and INSANE dehumidifier cost
« on: August 02, 2016, 09:55:01 PM »
I just moved into a new-to-me house built in 1919. The basement is humid (around 60-70% humidity in a Minnesota summer), and the prior owners left a dehumidifier. It's a Kenmore 70 pint model, and it always seemed to be draining, so I thought everything was fine even though the basement didn't get to the 50% humidity that the dehumidifier was set to. (Meaning that the dehumidifier was running constantly.)

Well, then I got my first electric bill for the new house and it's INSANE. Three times as high as the highest summer bill at my old place. Granted, that place was smaller, but it was a similar vintage and our usage patterns haven't changed that much. I was expecting 50% more electrical use than the old place. Not 300%.

I did some research and the 70 pint model seems oversized for the area of the basement (which is about 800 sq ft). I also went to the library and got a power meter (not a Kill-A-Watt, but a similar device called "Watts up?"), and my first suspect is the dehumidifier. I plug it in for an hour or so and it reads out AVE kWh/MO: 239. TWO HUNDRED AND THIRTY-NINE kWh/month??? That pretty much accounts for the discrepancy in energy use.

We tend to keep the windows open as much as possible, and only close them up/run AC when the temp is over 90. I've gotten conflicting advice as to whether a dehumidifier should be run when the windows are open. (The basement windows don't open, and the humidity doesn't seem to change when the basement door is closed all the time, although that door has a cat door cut in it, so maybe it's worthless from a restricting-air-flow POV.)

These are the options I'm seeing:
-Dehumidifier is broken, replace it and just suck it up that it'll eat $50+ in electrical costs per month (based on the energy star ratings of new models)
-Dehumidifier isn't broken, it just needs time to run and/or to not have outdoor air coming in all the time. Don't replace, and just suck up the $50+ in extra electrical costs per month
-Find a non-electric DIY solution (I'm seeing options for CaCl2 in a bucket online; has anyone tried that?)
-Run the A/C all the time upstairs (not central air, window AC units), keep the windows closed, and between that and the dehumidifier the basement should be fine (although my wallet and general sense of environmentalism would not be)

Does anyone have any ideas? Thanks!
« Last Edit: August 02, 2016, 10:13:52 PM by merula »

DoubleNickels

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #1 on: August 03, 2016, 06:08:17 AM »
Following as I'm seeing the same issue.  Dehumidifier a are expensive to run.  Period.  Will I regret it if I don't?

kpd905

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #2 on: August 03, 2016, 06:39:18 AM »
239 kwh/month will cost you about $26 per month.  That assumes it never stops running.

ender

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #3 on: August 03, 2016, 06:41:49 AM »
So you basically are continuously flooding your house with humid air most of the summer unless it's more than 90 outside and are surprised it costs a lot to run your dehumidifier.

You could look into more energy efficient dehumidifier though I'm not sure how new yours is.

It sounds like you keep windows open most of the time, so the concept of "airtight"ness is pretty much meaningless upstairs. A lot of ways to reduce dehumidifier use involve carefully keeping your home airtight when running AC.

Do you run your furnace fan during the day? You might try playing with this somewhat.

Also, you might try experimenting running your AC when it is a lower temperature outside. Hotter air can contain more water and air conditioners remove quite a bit of water from your air as part of their cooling process.



But unfortunately you might just be out of luck.

239 kwh/month will cost you about $26 per month.  That assumes it never stops running.



Yeah, I'm not really sure what the 300% translates to in actual dollars. I'm assuming merula's calculations put it way higher, because I doubt that their previous electric bill was only about $7..
« Last Edit: August 03, 2016, 06:48:49 AM by ender »

Papa bear

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #4 on: August 03, 2016, 06:46:59 AM »
Is the humidity causing damage in the basement?  Standing water? Mold? Mildew? Smell funny?  Rusting appliances and other metal objects?  I'd live with the humidity if it wasn't causing issues.  If it is, run your AC a bit more.


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rubybeth

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #5 on: August 03, 2016, 06:51:56 AM »
We bought a dehumidifier for our apartment years ago since the window/wall AC doesn't really dry out the 750 sq. feet enough for our comfort. All of the information that came with it said to only run it when windows are closed. I would try keeping the AC on and windows closed--you can keep it at a high enough temp that the AC isn't running all the time or making it too cold--and see if that helps. The AC should help.

For a comparison, our usual winter electric bill for our apartment in Minnesota is around $30 (lights, electronics). In the summer, running window AC and dehumidifier, it's about double ($60) but totally worth the $30 to be able to sleep with these horrible humid weeks we've been having.

You could also try getting a newer dehumidifier (we got ours at Mills Fleet Farm, I think it's a GE or something), and see if it's more efficient, but I doubt it.

Other option: have a whole house dehumidifier installed. My parents have one and it's pretty nice, but not exactly going to save you money in the short term.

GuitarStv

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #6 on: August 03, 2016, 06:55:57 AM »
Is your basement finished?  If not, it's possible to finish and properly insulate a basement so that humidity problems are significantly lessened.

How good is the airflow in your basement?  Humidity doesn't do as much bad stuff if you have excellent airflow.  Many basements don't do very well on this mark though.


A simple thing that you can do regarding humidity is to open your windows only during the night when it's cooler to let the house air out, then close everything up tight during the rest of the day.  Run your house fan during the day to keep air circulating.  As your home warms up over the day the relative humidity in the house will drop.  Couple that with occasional dehumidifier or A/C usage during the day and you should keep a comfortable humidity level in the house.

merula

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #7 on: August 03, 2016, 07:23:56 AM »
Thanks everyone.

The kWh cost is low (actually only about 60% of the bill I'm looking at), the rest is fuel surcharges and taxes, so I'm fairly confident in my assessment of the total running cost. A later test was showing closer to 300 kWh.

I don't have a furnace or a furnace fan; the house has radiant hot water heat. I did see something about a basement fan that vents outside? Not sure what that would do, but seems like a relatively cheap solution if it'd work. I'm guessing that a whole-house dehumidifier system needs air vents, which I don't have.

I'm not really seeing much of an issue in terms of moisture impact, other than it "feels" humid down there. No rusting appliances or mildew. There is water after rain in one portion (a 1950s-era addition that wasn't as well done as the 1910s original), but we're working on addressing that by caulking stuff up inside and improving rain flow away from the house on the outside. I'd love to just leave it (in fact, that's what I'm doing now as I'm researching the issue), but I'm concerned that I might cause future issues. If I start getting mildew, can I just run the dehumidifier then to kill it? Or is it possible that if the high humidity is only seasonal (winters in Minnesota are SO DRY), that would inhibit longer-term moisture issues?

Rubybeth, your electrical costs seem pretty close to mine, though a little lower. I'm open to running the AC when it's cooler, but wouldn't that be a significant increase in the energy use, even compared to the crazy dehumidifier? Husband and children are home during the day, if that matters.

The basement is...partially finished? And I don't mean that part of it is finished and part of it isn't; I mean that someone framed out walls and ceilings (but not floors) across most of the basement at some point. The most recent prior owners tore out part of the drywall on one wall, but I don't know if that was for moisture issues or aesthetic effect.

Has anyone heard anything about calcium chloride (that is, road salt) dehumidifiers? It seems like an extremely mustachian solution (salt in a colander over a bucket, salt absorbs moisture, brine drips into bucket, evaporate the brine back to salt and repeat), but does it actually work? And  how concerned should I be about small children getting into something like that? (They're not typically in the basement alone, though.)
« Last Edit: August 03, 2016, 07:25:58 AM by merula »

muckety_muck

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #8 on: August 03, 2016, 07:25:02 AM »
Our dehumidifier isn't expensive to run... we set it on 55% and it cycles throughout the day. We usually empty it once a day. There's a big bucket at the bottom we pull out & dump. It's a pain but it keeps our AC from running double time, hence the money savings. We do not leave windows open however. That would allow so much more humid air to come in. Once the weather cools off, we will open windows and only run the humidifier at night when the windows are closed. But summertime? windows/doors closed, AC and dehumidifier on allllllll day.

rubybeth

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #9 on: August 03, 2016, 08:19:41 AM »
Rubybeth, your electrical costs seem pretty close to mine, though a little lower. I'm open to running the AC when it's cooler, but wouldn't that be a significant increase in the energy use, even compared to the crazy dehumidifier? Husband and children are home during the day, if that matters.

Possibly, but the thing is keeping your windows closed without AC would be uncomfortable to me. I just wonder if the basement would be dryer with windows closed and AC on a pretty high temperature setting. Keeping the windows open with a dehumidifier running goes against the recommendation on my dehumidifier, so I wouldn't do it. I am just guessing that's part of why it runs constantly.
« Last Edit: August 03, 2016, 12:21:39 PM by rubybeth »

GuitarStv

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Re: Humid basement issue and INSANE dehumidifier cost
« Reply #10 on: August 03, 2016, 08:32:34 AM »
A dehumidifier works in a very similar way as an A/C unit, it just vents the hot air into your home rather than outside.  Which one uses more energy is going to be specific to which model you get . . . but the dehumidifier will always increase the heat in your home, which you'll then have to deal with.