Dehumidifiers and CPS Bills (for sale, how much, house)

[scuba steve]

So I've been running my a/c units at about 76 which keeps them off for most of the day according to the usage button. They're 4 year old energy star rated models so when they come on, they don't run long. Problem is, now the house is getting humid even with the air circulation fan running all the time.

I'm curious how well dehumidifiers work in this area, and what their impact on the electric bill is. Some of these things have energy star labels, but uf I have to use one or more to keep the humidity down and they draw a lot of power at some point I might as well just run the a/c more. The downstairs area is a bit under 2K square feet and upstairs is a bit over 1K I think.

Since the air return vent downstairs is next to the floor I was thinking about putting one near that so the dryer air gets circulated about. But also, these things come in all sizes so how many cfm might be best? Maybe a big one since it might work for the whole bottom floor rather than try and go at it room by room? It seems like the nicer ones have controls that'll turn them on at a certain humidity level.

There's gotta be someone else out there who's tried one to help lower their CPS bills...

[sapphire]

From the energy star website:
Dehumidifiers : ENERGY STAR

Doesn't look like it would be worth it for a money-saving venture, but will it make your home more comfortable? I asked at Home Depot the other day, and the lady working there was not very knowledgeable.

Also, just an FYI--check bcad.org for your square footage up and down. It's accurate for my house, so I'm assuming it is for most people's homes.

[scuba steve]

Interesting reading. I didn't take into account the fact that the things do generate a small amount of heat as they work. And there aren't any mold problems or anything here. I'm probably just too used to being somewhere with much lower humidity. For whatever it's worth, I have the total square footage for both the house and lot. Just not how much of it is distributed upstairs and down. Of course if I could ever track down who in the world the builder was maybe they'd have an idea...

Really the question becomes whether or not the tradeoff in terms of kicking out a little heat and using however much electricity is worth it compared to running an efficient but large a/c to bump the temperature down some.

[scuba steve]

Might've found the answer here:
EERE Consumer's Guide: Central Air Conditioners

The Department of Energy says no, it's not a good idea.

Air conditioners help to dehumidify the incoming air, but in extremely humid climates or in cases where the air conditioner is oversized, it may not achieve a low humidity. Running a dehumidifier in your air conditioned home will increase your energy use, both for the dehumidifier itself and because the air conditioner will require more energy to cool your house. A preferable alternative is a dehumidifying heat pipe, which can be added as a retrofit to most existing systems.

The problem is, this thing looks like something for commercial applications. Has anyone tried one for residential purposes?

[wCat]

Hello SSteve! When we had horrendous rainfall non stop for months on end last summer, I HAD to go buy a dehumidifier. The house was sort of split level and the lower level stayed damp and humid....even on cooler days. (Pier and beam construction too!) I sprung for a moderately priced dehumidifier and it did make a good bit of difference in the moisture in the air....but not enough for my liking. I'll just say it made it tolerable to sleep at night even with a cool AC running. It definitely warmed up the room during certain parts of the day, PLUS it was very loud.

On top of that, it definitely sucks a lot of power to run. All in all, unless you have major allergy probs that need dryer air, or just cannot sleep in a humid climate, I'm not sure it's worth it. I paid about $160 for the one I got, just for one area of the house. (about 700sq feet).....plus the added cost to the electric bill ????? It sucked about 12 gallons of water out of the air every 24 hours last summer! I am NOT kidding!

If you want to be green, humid free and energy friendly.....this wasn't doing it!

[texdav]

You definite have a humidy problem. If your air conditioner has a expension value then it will handle the humidity much better allowing you to run it at a higher setting with confort. That what i am getting as my mother in loaw had one installed and it really make a difference. They are more expensive units tho.

[scuba steve]

I'd really hate to replace the a/c and furnace since they do a great job of cooling and is quite new still. No idea if it has an expansion valve or not (I thought all systems did; at least they do on cars). The Frigidaire ones for sale at Lowes are really tempting though since they can come on at a particular humidity level. Does anyone here have one? I can't find a lot of reviews for the things online, or info about the amount of db they generate.

[Chaka]

Hmmm, we used to use a dehumidifier because we didn't have *any* a/c. I don't recall any significant increase in our CPS bill those months, but it's not like we ran it all the time. I'm sure it cost some, but wasn't like our bill doubled or anything.

Now we have a/c, we almost never use the dehumidifier, it's rare for it to be cool enough to not use it. I'm impressed your house stays at 76F most of the day! We set ours to 80F when we're home and our house is well shaded with high ceilings and it still runs a fair amount. We have used it once or twice when it's been cool enough already and we didn't want to set the a/c even lower.

[scuba steve]

The a/c is at 78 during the daytime; 76 otherwise. Between midnight and when I get home in the afternoon the a/c runs for an hour and some change altogether and those times are when it feels the most humid. During the daytime, and at night because it's such a long period of time that the a/c doesn't run. In order to keep the humidity down so that you don't notice it, I have to set the temperature to 73-74 and that's when usage and bills start to increase (and it feels much colder inside).

The fact that the place can keep itself right around the 80 degree mark without running the a/c too much is probably due to there being tons of blown-in insulation in the attic. Everywhere except around the attic ladder and furnaces is at a minimum of 20 inches deep. Anyway I'm going to ask the other two people at home what they think today when I get back from work, and maybe pick up something depending on what they say. Thanks for letting me know about how yours impacted the utility bills!

[ddrewa]

try moving your thermostat fan setting from ON to AUTO. that should keep things much drier.