Author Topic: Normal that dehumidifier runs 24/7 May-September? Electricity bills high.  (Read 1116 times)

J Boogie

  • Pencil Stache
  • ****
  • Posts: 737
I've got a MN duplex built in 1890 that has your average stone foundation. Radiant heat, not forced air. We'll be installing a minisplit for AC in a couple days.

When I bought it I noticed it smelled a little musty in the basement so about a year ago I bought a dehumidifier and have it running whenever the RH is at 65 or above.

I hooked it up to the drain so it doesn't stop.

I don't have any major grading issues, I could put a lot of effort into keep rainfall even further away from the house - but I'm not sure the juice will be worth the squeeze. I have a huge list of things to work on for this house so I'd hate to invest hours and hours into something that doesn't make a big difference.

I am replacing my old rotted basement windows with new vinyl units that actually open so I can ventilate on mild and cooler days. This could help during spring and fall and cooler summer days. I don't think it'll help on really warm days because the warm air meeting the coolness of the basement is a recipe for moisture.

Xcel energy always sends me emails showing me the difference between me and my neighbors electricity usage. I use way more than they do (my tenants have their own electric bill btw) Am I the only one trying to keep my basement dry? Am I going about it the wrong way? People lived here long before dehumidifiers were built so I'm wondering if the basement was always musty or if they had some tricks up their sleeve.

Any input welcome. Thanks in advance!






LifeHappens

  • Magnum Stache
  • ******
  • Posts: 4951
  • Location: SnowBirdLand
  • Downshifting from 5th to 3rd Gear
I grew up in the Upper Midwest in a house with a stone foundation basement and no dehumidifier. The basement was always super musty in the summer. My childhood home is on a small hill and the soil is sand so water drainage was never an issue. It's just the nature of the foundation material, the high humidity and the warm air temperature.

What are you using your basement for? If it's just storage, I personally would run the dehumidifier far less. If you want it for living space that's a whole other level of cost and complexity.

I'm a red panda

  • Walrus Stache
  • *******
  • Posts: 7279
  • Location: United States
A musty basement sounds like an invitation for mold.  I'd just run the dehumidifier.


(Ours runs most of the summer. Ironically, we then run a humidifier most of the winter)
« Last Edit: July 13, 2018, 11:31:05 AM by I'm a red panda »

J Boogie

  • Pencil Stache
  • ****
  • Posts: 737
I grew up in the Upper Midwest in a house with a stone foundation basement and no dehumidifier. The basement was always super musty in the summer. My childhood home is on a small hill and the soil is sand so water drainage was never an issue. It's just the nature of the foundation material, the high humidity and the warm air temperature.

What are you using your basement for? If it's just storage, I personally would run the dehumidifier far less. If you want it for living space that's a whole other level of cost and complexity.

Storage, laundry room, woodworking, surplus shelf (an extended pantry of sorts - allows me to stock up on food items & consumables with relatively long shelf lives on a very occasional basis, limiting grocery trips to meat and produce).

Mold, naturally is the concern. My family's respiratory health is important to me. I imagine if we didn't have any organic material down there, we could allow it to get as humid as ever without risk of mold. But organic material tends to find its way into places, and mold will develop if the conditions are right.

Even if we didn't spend any time there, I would think that the presence of mold in the basement could potentially affect our air quality in the rest of the house as well.

That does help answer my question - maybe my neighbors just have musty basements. I don't know. Thanks for your input!




LifeHappens

  • Magnum Stache
  • ******
  • Posts: 4951
  • Location: SnowBirdLand
  • Downshifting from 5th to 3rd Gear
I guess you could ask your neighbors about their basements. It's always possible there is a hidden problem causing yours to be worse.

I understand your concerns about mold. Painting your basement walls with dri-lock paint is a cheap-ish option to keep out moisture if you find some seeping through the walls. You can also use air drying crystals in particularly musty corners.

Sibley

  • Magnum Stache
  • ******
  • Posts: 3220
  • Age: 33
  • Location: Chicago, IL
Dehumidifiers typically have a filter. Make sure it's clean. that will help with energy usage a tiny bit.

J Boogie

  • Pencil Stache
  • ****
  • Posts: 737
Dehumidifiers typically have a filter. Make sure it's clean. that will help with energy usage a tiny bit.

Thanks for the tip - My basement has been pretty dusty lately as I've been repointing the foundation.

Car Jack

  • Pencil Stache
  • ****
  • Posts: 832
Is there any way that you can fit an AC unit in a basement window?  I'm sure you know that a dehumidifier is nothing more than an AC unit that you don't get the benefit of cooling from.  If you could put an AC unit in a window, you get the same dehumidifying effect but get the air cooled as well.

Indio

  • Bristles
  • ***
  • Posts: 286
  • Location: high cost of living area in east coast
Dehumidifiers typically have a filter. Make sure it's clean. that will help with energy usage a tiny bit.

Thanks for the tip - My basement has been pretty dusty lately as I've been repointing the foundation.

No joke, I forgot that my dehumidifier had a filter. I've looked for it in the past and couldn't find it so I thought it was filterless. Uh... dumb move. Aftter reading this thread, I went and checked again. I use a hose to drain it into the sump so never needed to take out the water chatch basin. Well, I found the filter hiding above the catch basin area right behind the vent, where it should have been all along. I just expected that it would slide out on the side, not pull down from underneath the vent. Anyway, I cleaned off 4 years of basement dust. It was nasty!!! Funny coincidence is that I was thinking, when I did a load of laundry this morning, that the basement was unusually humid.

merula

  • Handlebar Stache
  • *****
  • Posts: 1128
I live in MN, in a house built in 1919, also with radiant heat. Foundation is concrete block rather than stone, but effectively the same for what we're talking about.

The ultimate issue with basement humidity isn't necessarily grading and moisture through the foundation (though that can contribute), it's the hot, moderately humid MN summer air cooling to basement temperatures, which increases the *relative* humidity of the air.

If you're sure that there's not much to be done from a grading issue* (no wet basement, no wall efflorescence), then the best approach is to run a dehumidifier. Depending on the strength of your dehumidifier and the size of your basement, running 24/7 may be a legitimate need.

If you're in the Twin Cities metro, I know that many library systems have electrical use meters available that you can use to see how much energy your dehumidifier is actually using. I replaced my unit last year, and I found that the electrical use dropped dramatically with the new unit while the humidity was managed much better. The difference in electrical use may not be entirely the dehumidifier.

Here's some anecdata from my extended family's homes in the MN/WI area:
-My house: built 1919, 1400 sq ft above ground, semi-finished basement, no central air, limited AC use upstairs, none in the basement. Dehumidifier is always plugged in and set for 60%. I keep my basement windows closed on the theory that it's easier to remove the humidity from a relatively static amount of air than from constant in-flows.

-House #2: built 1970, 2000 sq ft, finished basement, central air, basement humidity issues. Apparently, when this house was first purchased, the dehumidifier ran 24/7 and put out massive amounts of water. After a few years, it cut back to running only sporadically but the humidity was under control. Homeowner's theory is that the first few years of dehumidifier use "dried out" the foundation. I'm not sure I agree, because they also had the typical winter super-low humidity, so wouldn't that have continually "dried out" the foundation? They did some landscaping work including grade improvements for unrelated reasons, so my bet is that was the true cause.

-House #3: built 1990, 3000 sq ft, finished basement, central air, constant A/C use, no basement humidity issues. (Probably because the temperature and humidity differentials between the basement and upstairs are minimal.)

-House #4: built 1950, 2000 sq ft, unfinished basement, window A/C, basement humidity issues, Dehumidifier runs 24/7. Homeowners keep basement windows open.

-House #5: built 1920, 2000 sq ft, unfinished basement, window A/C, no basement humidity issues. (I cannot personally figure out how that works, but good for them.)

*Grade improvements don't have to be expensive. We've been dumping extra dirt, compost, mulch, whatever extra yard material we have in the berm areas on the side of the house with grade issues and over 2 years have built up a solid extra foot with minimal actual work and no extra cost.

merula

  • Handlebar Stache
  • *****
  • Posts: 1128
Is there any way that you can fit an AC unit in a basement window?  I'm sure you know that a dehumidifier is nothing more than an AC unit that you don't get the benefit of cooling from.  If you could put an AC unit in a window, you get the same dehumidifying effect but get the air cooled as well.

This works if there's a benefit to cooling the basement air. The drawback is that cooler basement air will require more water removed to get to the same relative humidity as slightly warmer basement air.

I don't want to speak for the OP, but my basement is typically in the 69-71 range if I don't run the dehumidifier and 72-73 if I do. The basement is plenty cool either way, so if the goal is lower relative humidity, the more efficient approach is to remove water and increase the temperature.

BudgetSlasher

  • Pencil Stache
  • ****
  • Posts: 548
Is there any way that you can fit an AC unit in a basement window?  I'm sure you know that a dehumidifier is nothing more than an AC unit that you don't get the benefit of cooling from.  If you could put an AC unit in a window, you get the same dehumidifying effect but get the air cooled as well.

This works if there's a benefit to cooling the basement air. The drawback is that cooler basement air will require more water removed to get to the same relative humidity as slightly warmer basement air.

A heat pump water heater is an option as well. While our dehumidifier did not run 24/7 before switching to the heat pump water heater, the switch did significantly decrease the time the dehumidifier is running. Cooling and dehumidification are by-products of heating the water and the heat is not wasted, either outside as with a AC or back into the room as with a dehumidifier, but a dehumidifier/AC will still be needed to maintain the humidity level. I joke that any time the dehumidifier is running the hot water is essentially free. 

TheWifeHalf

  • Bristles
  • ***
  • Posts: 499
We live in a circa 1915 house and run the dehumidifier 24/7 in the summer, in Ohio.
We run it in the winter, probably half as much.
Somehow, TheHusbandHalf has a hose hooked to it so the water goes directly into where the sump pump is.
« Last Edit: July 21, 2018, 10:11:23 AM by TheWifeHalf »

FIKristen

  • Stubble
  • **
  • Posts: 102
Is there any way that you can fit an AC unit in a basement window?  I'm sure you know that a dehumidifier is nothing more than an AC unit that you don't get the benefit of cooling from.  If you could put an AC unit in a window, you get the same dehumidifying effect but get the air cooled as well.

This works if there's a benefit to cooling the basement air. The drawback is that cooler basement air will require more water removed to get to the same relative humidity as slightly warmer basement air.

A heat pump water heater is an option as well. While our dehumidifier did not run 24/7 before switching to the heat pump water heater, the switch did significantly decrease the time the dehumidifier is running. Cooling and dehumidification are by-products of heating the water and the heat is not wasted, either outside as with a AC or back into the room as with a dehumidifier, but a dehumidifier/AC will still be needed to maintain the humidity level. I joke that any time the dehumidifier is running the hot water is essentially free.

Agree on this.

Also, is your existing dehumidifier Energy Star certified?    An Energy Star one will use ~30% less energy for the same amount of dehumidification.    Depending on how high your bills are it might be worth considering replacing with a more efficient unit.

BudgetSlasher

  • Pencil Stache
  • ****
  • Posts: 548
Is there any way that you can fit an AC unit in a basement window?  I'm sure you know that a dehumidifier is nothing more than an AC unit that you don't get the benefit of cooling from.  If you could put an AC unit in a window, you get the same dehumidifying effect but get the air cooled as well.

This works if there's a benefit to cooling the basement air. The drawback is that cooler basement air will require more water removed to get to the same relative humidity as slightly warmer basement air.

A heat pump water heater is an option as well. While our dehumidifier did not run 24/7 before switching to the heat pump water heater, the switch did significantly decrease the time the dehumidifier is running. Cooling and dehumidification are by-products of heating the water and the heat is not wasted, either outside as with a AC or back into the room as with a dehumidifier, but a dehumidifier/AC will still be needed to maintain the humidity level. I joke that any time the dehumidifier is running the hot water is essentially free.

Agree on this.

Also, is your existing dehumidifier Energy Star certified?    An Energy Star one will use ~30% less energy for the same amount of dehumidification.    Depending on how high your bills are it might be worth considering replacing with a more efficient unit.

energy star reminds me, there are also dehumidifier that are rated for the cooler temperatures found in basements.