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Dehumidifier unit vs AC/Dehumidifier combo

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Forum topic by TellMePlease posted 08-05-2020 02:13 PM 284 views 0 times favorited 9 replies Add to Favorites Watch
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TellMePlease

136 posts in 86 days


08-05-2020 02:13 PM

Topic tags/keywords: question

When looking at what I want to do for climate control, it seems that dehumidifying is the key component to protecting my equipment. Heat and air are great, but seems solely for comfort. I probably am going for a walk AC unit for affordability….

With that said, is the combo units good at dehumidifying and sufficient if it has a “dry mode” to run it? Or should I buy the two separate? No need to buy the combo if the ones built into AC units are not sufficient. I can’t seem to find that comparison anywhere on the net.


9 replies so far

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controlfreak

1217 posts in 449 days


#1 posted 08-05-2020 02:43 PM

From what I understand about home AC units is that it is important to size the unit for it to have sufficient run time to dry the air. An oversized unit can cool too fast and cause a mold problem. That’s my full expertise on the subject. I would go for a unit that can do both.

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houblon

56 posts in 2501 days


#2 posted 08-05-2020 02:52 PM

I used to run a dehumidifier in my basement all summer to keep humidity down. But that would bring the temp up to 90 towards the end of summer.
Now I run a small window unit AC in my basement when it is hot which is sufficient to keep the temp & humidity down.
When the outside temp goes down, I need to run both: dehumidifier brings down humidity and raises temp, AC lowers temp (and helps a bit with humidity), but AC alone would not run sufficiently to bring down humidity.
I do the same on the ground floor where we have instruments that need protection from high humidity.

I don;t know what a combo unit is. Our windows AC has a settings that says “Dry”, but I have no idea how this is supposed to work without simultaneously cooling.

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2Goober

19 posts in 450 days


#3 posted 08-05-2020 02:57 PM

I just got off the phone with my son who owns a HVAC company. He said the Mini Split option is the one that has the “drying” function. It is more expensive, however it is MUCH more efficient (about 50% as compared to a window unit) and will run at about 30% power when the A/C is not needed. The 30% is the drying function. These units also have a heat pump built in to take care of your winter needs. These units cost more to install and run more, however they use less electricity because they are way more efficient.
I’m really glad you asked this question because I use a window unit for the A/C and a little propane ventless heater in the winter. This is something that I have been thinking about for a while so I called him.

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TellMePlease

136 posts in 86 days


#4 posted 08-05-2020 03:05 PM

My question is geared more towards…

Option 1: Buy the wall a/c unit With built in humidifier

Option 2: Buy wall AC unit without dehumidifier and buy a dehumidifier as a separate unit

My winters are not so harsh… there are ways to heat up fairly cost effectively. Not to mention I love food and it’s already like I have a built in thermal blanket under my skin.

https://www.google.com/shopping/product/7789346623374286961?q=koldfront+dehumidifier&safe=active&client=safari&hl=en-us&biw=414&bih=719&tbs=vw:g,ss:44&prmd=sivn&prds=epd:9237493631622535977,cdl:1,prmr:1,cs:1
Combo unit

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houblon

56 posts in 2501 days


#5 posted 08-05-2020 03:11 PM

Any AC unit dehumidifies automatically. There is no cooling without de-humidification.

A standalone dehumidifier is the same as a AC windows unit, with the difference that the cool air gets heated up again and blown back into the room (with extra heat).

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controlfreak

1217 posts in 449 days


#6 posted 08-05-2020 03:25 PM

Yeah a dehumidifier is a zero sum game. The cooling coil cools as much as the warming side heats it back up. The reason it gets hotter is the energy input to the motors and friction. It reminds me of a physics test question where a refrigerator is placed in a perfectly insulated room (not possible but work with me here) and the room has one power outlet. What happens to the room temperature if the refrigerator door is left open? It gets hotter.

All that said space is at a premium in my shop so I would get both in one unit.

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houblon

56 posts in 2501 days


#7 posted 08-05-2020 03:43 PM


All that said space is at a premium in my shop so I would get both in one unit.

- controlfreak

Please proof me wrong, but I believe there is no combined unit availabe. I could not find a device that de-humidifies without cooling, or without heating.
AC has the compressor (where heat is created) outside of the building. Inside it is either cooling + dehumidifying, or nothing.
Standalone dehumidifyer has the compressor inside the building to warm up the cooled air, and thus created excess heat.
A truely combined unit must have part of the decompressor outside and part of it inside. I could not find such a device.

View Fred Hargis's profile

Fred Hargis

6415 posts in 3341 days


#8 posted 08-05-2020 03:55 PM

“Many of the ones called a ””portable” unit” are often listed as dual function. These things are not that great. They do blow the heat outside through a hose run to a window vent, but in my case (this is guess work on my part) because they are blowing air out, it leaks into the shop from the outside. If it’s really hot outside, so is that air…making the unit work harder and still not cool. I gave mine to the Habitat Restore and bought a window unit. When it’s not hot enough to cool the shop, I run a stand alone dehumidifier.

-- Our village hasn't lost it's idiot, he was elected to congress.

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controlfreak

1217 posts in 449 days


#9 posted 08-05-2020 04:25 PM


All that said space is at a premium in my shop so I would get both in one unit.

- controlfreak

Please proof me wrong, but I believe there is no combined unit availabe. I could not find a device that de-humidifies without cooling, or without heating.
AC has the compressor (where heat is created) outside of the building. Inside it is either cooling + dehumidifying, or nothing.
Standalone dehumidifyer has the compressor inside the building to warm up the cooled air, and thus created excess heat.
A truely combined unit must have part of the decompressor outside and part of it inside. I could not find such a device.

- houblon


I put in a window unit and it has a “dry” setting but like you I can’t see how that works. My best guess is that it runs the fan more and cycles the cool on and off instead of full on. In my climate it is humid when hot and dry when cold. The change from needing heat or air happens in about a three week span. So I just let the window unit keep moisture down and hop for the best. If I see rust I will add a dehumidifier

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