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Whole house dehumidifiers?


Swamp_Yankee

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As you can tell from my other thread I'm declaring war on humidity.  I'm in a 150 year old farmhouse with no ductwork (hydronic baseboard heat) and this summer our window units did keep the house cool, but could not keep up with the humidity. Now that we're into October, the window units are out, but even in the cooler temperatures, the humidity is still regularly hitting 90%. I've been finding mold and mildew in closets, the basement, etc... I've been looking at freestanding and ducted dehumidifiers( the big boys that do 90-120 pints a day like Sante Fe, Aprilaire, etc...not the crap you get at Lowes/Home Depot) but I can't decide which would better suit our house. The basement is a combination of rubblestone and block foundation with a poured floor. We don't get any seepage (house is built into a hillside and everything drains away) but it does get damp. The first floor (about 1300 SF) is very open. The second floor (also about 1300 SF) has 5 bedrooms and one bathroom off of a central L-shaped hallway. There is a walk-up attic above the entire 2nd floor. 

One of the options I've thought of is to buy two freestanding units, put one in the basement and one in attic, and simply punch holes in the first floor and second floor ceiling, install register covers, and hope that there is enough air exchange through those to lower the humidity throughout the house. Option two of course, would be to install a ducted unit or units and at a minimum, install one return and one delivery on each floor. Any thoughts?

I live back in the woods you see

My woman and the kids and the dogs and me

I got a shotgun a rifle and a four wheel drive and a country boy can survive

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3 minutes ago, Nomad said:

Put central ac in and kill two birds with one stone

Good idea but expensive.  You can put a vent fan to the outside and set it up with a humidity sensing witch. https://www.graybar.com/manufacturers/leviton/humidity-sensor

Just add a radon fan and a perforated pipe and vent it to the  outside. I put in a dehumidifier with a built in tank pump with this setup at my place on the Cape.  Works fine so far.

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I have a sani dry unit in the basement.  Had mold problems even during dry years while using a large sears model dehumidifier running all the time.  Got the sani dry basement floor model and it has cured the problem.  It has a separate pump container with tube that pumps it into the washing machine drain when full.  Comes on when it senses moister, and the moister level can be adjusted.  Fan can run continues or just when the dehumidifier comes on.  Also filters the air.

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I have a basement that gets wet when it rains but otherwise stays dry.  If I do not run a dehumidifier in my basement, it gets nasty down there.  I have one of these running 24/7 with a hose into the sump pump.  It's been running for about 3 years non-stop so far.

https://www.amazon.com/gp/product/B00UWP07LK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

It does the job.  Keeps the humidity at or below 40% and even lower in the winter.  In the winter the unit will actuality shut off if I have it set to 35%.

The key thing about a dehumidifier is where you locate it in your house.  My basement is unfinished and the dehumidifier is in the middle of the basement.  This ensures that everything is evenly dry and there's decent airflow to/from the unit.  They draw air in from the back and then expel it from the side.  It's warm air, so expect wherever you run it to be warmer than normal.  Good in the winter, not so good in the summer.

AC in my house increased the humidity.  The AC keeps the humidity around 40%-50% in the summer.  I thought it would have dehydrated the house, but that's not how it works (or at least mine).

Sapere aude.

Audeamus.

When you cannot measure, your knowledge is meager and unsatisfactory.

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2 minutes ago, Haskell_Hunter said:

 

It does the job.  Keeps the humidity at or below 40% and even lower in the winter.  In the winter the unit will actuality shut off if I have it set to 35%.

 

My coils freeze up if I run it in the late fall, winter, or early spring, when it is colder down in the basement.  Maybe I need a newer unit?  Mine is about 20 years old.

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7 hours ago, Nomad said:

My coils freeze up if I run it in the late fall, winter, or early spring, when it is colder down in the basement.  Maybe I need a newer unit?  Mine is about 20 years old.

I think you have my AC and dehumidifier confused.  I turn the AC off in October, the DH runs 24/7 and is set to shut off when the humidity inside goes below 35%.

Sapere aude.

Audeamus.

When you cannot measure, your knowledge is meager and unsatisfactory.

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Did a little more research and talked to a tech support rep from Santa Fe and am pretty close to pulling the trigger on this one:

https://www.sylvane.com/santa-fe-advance90-dehumidifier.html

He said that most of his customers will locate a unit like this in the basement or crawl space, run it full bore, and that once the basement is drawn down to between 50-55% humidity the first floor will usually come down to 60-65%, which most people consider comfortable.  Made in Madison, WI too.  

I live back in the woods you see

My woman and the kids and the dogs and me

I got a shotgun a rifle and a four wheel drive and a country boy can survive

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We had an issue in my town hall this summer. The women didn't want the ac on but were complaining about the humidity. They asked about a whole building dehumidifier and the hvac tech explained that the ac already does that and will work the best. They didn't want to believe him and now have a dehumidifier in every office.   

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11 minutes ago, Shakyjake said:

We had an issue in my town hall this summer. The women didn't want the ac on but were complaining about the humidity. They asked about a whole building dehumidifier and the hvac tech explained that the ac already does that and will work the best. They didn't want to believe him and now have a dehumidifier in every office.   

Dehumidifiers and AC units function the exact same way with one major difference.  With an AC unit, the humid air is drawn through the cold side of the heat exchanger to remove the humidity and then sent directly into the room-the hot side of the heat exchanger is vented to the outside.  With a dehumidifier, the hot side of the heat exchanger is vented to the room, so the room ends up warmer, but also drier.  That's why dehumidifiers are most useful when its cold, wet, and humid, like right now.  No one wants to run their AC when its 65°F outside to begin with, plus depending on the type of unit you have, it may ice up in temperatures below 70°F.  

I live back in the woods you see

My woman and the kids and the dogs and me

I got a shotgun a rifle and a four wheel drive and a country boy can survive

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