Dehumidifiers??

I've never used a dehumidifier in my home, but I'm thinking about getting one for my condo. Also I have a relative who recently moved to the foggy part of northern California, and he's finding the humidity there to be a real problem (e.g., clammy bedsheets). I'm wondering (a) do they really work, (b) how much impact do they make on your electric bill and (c) does it make more sense to use one for just one room or can one unit work for an entire apartment?

In my case, I have central A/C for my small condo but it doesn't do a great job reducing humidity in the summer. In particular the bathroom and bedroom are a problem. Last summer I tried using a large tower fan to try to dry things out after showering, with limited success. I think a fairly small dehumidifier might suffice for me.

My relative lives in a larger apartment, I think 2 or 3 bedrooms, and he's a starving college student. I don't know if it's possible to get a dehumidfier that would work for the whole apartment or if he should just get one for his bedroom. He and his roommate tend not to turn the heat on in order to save on their electric bill, so in their case the cost to run a dehumidifier would be very important.

I appreciate any advice. Thanks very much!!

(a) Yes. A LOT.

(b) We've been using one so long I don't know how much it adds to the electric bill. But we had a flood in our basement a few years back that had to be dried out by running four industrial dehumidifiers 24 hours a day for I think a week. Each one of those was WAY WAY WAY more powerful than the kind of home unit you're talking about, they ran continuously rather than intermittently (oh man this is reminding me how loud and awful that was :eek:) and it cost us about $20 compared to our electric bill for the same month in the prior year.

In warmer climates a humidistat on the AC is supposed to be more energy efficient than a standalone dehumidifier.

The electric bill is going to be cheaper than the amount of stuff he'd have to replace because of mold otherwise. I've lost too much stuff to mold, to ever go without a dehumidifier again.

(c) It depends on how big his apartment is and how well the air circulates. Definitely he'd need to leave closet doors open, maybe cabinet doors too. A circulating fan will help.

(d) For northern California, make sure he gets a unit that's designed for low temperature operation. Otherwise it will be prone to icing up. Icing isn't that big of a deal as long as the apartment is occupied and he can turn the thing off for a while and let it melt, and you do get a sense after a while of how low you can set the humidistat without icing, but it's kind of a PITA ... if the place will be unoccupied for days at a time, then icing can be a problem when the unit runs continuously without taking any humidity out of the air.


As far as your own condo - normally the reason AC won't reduce humidity is because the compressor is too big for the amount of area it's cooling, so it doesn't run long enough to dehumidify. I don't know where your AC is in its life cycle, but if it's nearing when you'd have to replace it anyway, make sure you tell the installer about your humidity problems and size the unit accordingly.

I'm no expert on dehumidfiers, but we do have one in our basement where we have a dampness problem. Yes, it does help. I also had one in the basement of my first home. The one we currently have drains into our sump pit. That's handy. I had to empty the drain pan in my old one by hand and that can get old. The one we have now also has a meter that measures humidity. That's handy, too, so that it doesn't over dehumidify (which not only makes your air too dry, but also costs money). That's generally not a problem in our basement, but it ran far less this past summer during the drought. Noise is also an issue from the free standing units. I'm not sure if they list their decible level, but I know that I wouldn't necessarily want to listen to the dehumidfier in our basement all the time. But you could have yours set to run when you're not home or, if you get one with variable fans speeds, run it on a lower speed when you're home. A whole house furnane could be an option, too, although likely more expensive. I will admit that I don't know what our humidfier costs in terms of electricity.

If memory serves, they're often rated for how much square feet/square meters they'll cover, but I think that's just one factor to consider when deciding what size to get. The other is just how humid the room(s) are to begin with. Have you ever measured the humidity of your apartment? Also, do you have an exhaust fan in your bathroom? If it's not doing a good job of clearing out the humidity, you might consider upgrading it. How long do you typically run it after a shower? I've seen suggestions that they should be run longer after a shower than they often are. We run ours for about a half hour after every shower because it's not a particularly powerful fan.

I'd add that I think there are units that can bet set to turn off automatically if they get too cold. That might be a feature for your relative to look for.

(a) Absolutely. They are practically a necessity in the muggy summers we get here.

(b) We also have never been without one, but our old, noisy one finally quit a few years ago and we upgraded to a Sunpentown (I think ours is the 55 pint one and we got it through Amazon). It has made a difference in likely lowering our electric bill as it works so well, the a/c has noticeably run less, and we are able to set the thermostat at a higher temp, since we got it. Note that the pint total is water pulled out of the air, not the size of the bucket.

(c) Here in the midwest, almost everyone with a house has a dehumidifier and keeps it in the basement - no need to have several all over the house. Ours is in the basement and our house is about 2000 square feet. Works great for the whole house.

We have a stand alone one in the lower level of our house, which is actually 4 levels. The lower level is real living space, including a family room, bedroom, bath, and laundry room/shop. The area is about 1,000 square feet and it smelled horribly when we moved in the house. We have the hose to it going directly outside, through the wall, where it runs down the hill.
It was noisy, so we moved it in the utility room. It works 100% of the time in the muggy New England summers. We have central AC but that was not enough.

We have one in our basement, but contrary to most everyone else, ours mostly runs only in the winter. ;-) It drains directly into the sump pit and it has a humidistat on it so that we don't have to monitor it. It works great to keep the basement at a normal moisture level. We noticed zero difference in our electric bill with it, but it's so minor compared to the other things we run (septic pump, two sump pumps, hot water heater, a server room and an entire kitchen of appliances) that it didn't register.

If you can't tell from my description, we have a VERY wet basement. We live in a valley and I'm fairly certain that we are the only house with a basement for miles because it's pretty much below the water table in the winter (when it rains daily for 9 months of the year). Between the two sump pumps and the dehumidifier, we've been able to store food, wine, linens, towels and paper things (like books) in our basement with no mold problems at all, so yes..they work.

Yes they definitely work. Don't know much more about them though. My parents have always had one in their basement. It drains into one of the drain spots in the floor of the basement of their home. Where I currently live (coastal NC) and where I used to live (Charlotte) we didn't really need one. Definitely didn't need one in Charlotte. Here's alot more humid in the summer, but doesn't seem to be an issue inside.