Dehumidifier, Humidex, or exisiting HVAC?

I am looking into options to dehumidify a basement in a home that I recently bought.
The basement is about 25'x30' with a high ceiling, has poured concrete walls, and two basement windows that are currently sealed shut (I just ordered replacement windows that I am waiting to come in). The basement is dry but it does have a sump pump that keeps it that way. I do know that before the sump pump was put in, the basement used to sometimes get water in it, but the sump pump fixed that (I know the prior owner). The house is located in Eastern Pennsylvania.
The only problem is that the basement feels just slightly damp and musty. A friend suggested putting a dehumidifier down there and I am in the process of searching the Internet for general info about dehumidifiers. One thing I just ran across was an ad for a Humidex system, but that looks like all it really does is bring whole house air into the basement and vents air to the outside.
Here's what I am wondering. Would one possible option be to just make sure the HVAC has an air intake in the basement so the basement air will get circulated throughout the whole system along with the rest of the house air? The way it is set up now, the basement is pretty much isolated from the rest of the air circulating throughout the house. The house has central air and an electric heat pump for heating.
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There are many basements that are not finished and may feel a bit damp compared to the rest of the house and still be OK without needing dehumidification. If the humdity is so high that mold, condensation, use for storage of dry goods, etc is an issue, then I would go with a dehumidifier.
I took a quick look at Humidex and not impressed. Basicly, it appears they suck air out from the basement floor and have it replaced with air from above, coming from the conditioned living space. That's a bad idea energy wise. In winter, for example, you'll be expelling basement air and replacing it with warm air from the house. Then, cold outside air has to come into the house through leaks, etc, to make up for the outgoing air.
You could use the house heat/AC to provide some air and take it away from the basement. But then you're again wasting energy in the basement by heating/cooling it. And if the basement has a musty odor, that may come with it into the house as well.
So, I'd go with a de-humidifier, which addresses the real issue and is IMO going to be the most energy efficient.
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It's more efficient to circulate air between the house and the basement when the basement RH is over 60%, using a humidistat.

Not much.

No way, IMO. And basement air can provide a little moisture in wintertime and a little cooling in summertime.
Nick
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On Sep 15, 11:26 am, snipped-for-privacy@ece.villanova.edu wrote:

I agree in the summer a cold air retun in the basement brings cool air into the system and helps dehumidify the basement. In the winter the basement is warmer because it's below ground so having a cold air retun in the basement works there too. The only way in the end to make a basement feel like living space is to treat it like living space with your HVAC system. Taking on a dehumidifier alone is not enough. Getting the downspouts to run water away and proper grading are the next thing that has to be right. Dryloc'ing the walls helps, and sealing the concrete slab with a latex liquid concrete sealer helps too. Of course obvious problems like seepage have to be fixed too. But mainly making the HVAC sytem also service the basement.
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If you buy a dehumidifier, stay away from the large Kenmore. It is junk. Look for a Whirlpool made in the US.

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on 9/16/2007 1:44 PM Art said the following:

I have a White-Westinghouse Model #MDH25WW1, 25 pint. I don't know where it was made because it doesn't say. I've used it for years in my basement. Works a charm.

--

Bill
In Hamptonburgh, NY
  Click to see the full signature.
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Thanks everyone.
I haven't moved into the house yet, but I went there on Saturday morning and checked out the HVAC duct work in the basement. There are no cold air returns and no supply vents in the basement. So the basement is completely isolated from the system. I found a place where I could easily open a 6" x 6" space in the cold air return duct and could feel the air being drawn in through the opening. About 6 hours later, it seemed like I could already feel a marked difference in the basement -- it didn't feel damp or musty at all.
I'm going to go back this week and check it again to see if that solved the problem. If so, I'll put an adjustable intake vent in the cold air return duct, and I'll add one or two adjustable supply vents for the basement.
It would be great if this simple change solved the problem and eliminated the need for a dehumidifier.

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