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Dealing With Heat From a Dehimidfier
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Author:  John Killin [ Sun Apr 28, 2013 2:12 pm ]
Post subject:  Dealing With Heat From a Dehimidfier
I have finally started to work on getting my humidity control in line. On my last guitar I braced it in the winter and although I didn’t have a hygrometer, I believe I was close to being in range. This is something I have to think about if I ever move the guitar to a different climate. That was the first guitar build I did and I was more focused on the construction side, rather than the long term effects of humidity.

I do most of my machine work and sanding in the garage. I have a work table in my office, inside the house, where I do bracing and setup work. Really anything that can be done without making a huge dusty mess. The house has central air, and the humidity this time of year is about 54% inside. This weekend I picked up a used LG Dehumidifier in an attempt to bring the humidity down to the low 40’s in the office. For the most part I can see where it will work. The big problem is the heat. The room gets hot. I can see where this would be great for the winter, but in the summer it isn’t quite going to work.

I’m wondering what other do. I hadn’t really thought about getting an AC unit for the room (since we have central air). My wife has put a stop to my trying to use one in the garage window so I’m pretty sure I’d be pushing it to try and install on in a room in the house. My hope had been that the dehumidifier would solve my problem.

I know several of you are using dehumidifiers in your shop\workspace. What do you do about the heat? I really want to make this work for a couple of reasons. One to control the humidity. Two I need to justify the dehumidifier purchase. I feel like that guy who bought a beer fridge and after he gets it home and talks up the pluses of having such a thing, realizes his keg system won’t fit in (not that I have ever been that guy). laughing6-hehe

Thanks,

John
Author:  Josh H [ Sun Apr 28, 2013 5:07 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
I had this issue at my first shop when I was just starting out. The only solution I found was AC. It helps to dehumidify the air as well meaning I did not have to run a dehumidifier near as much.

I would also invest in a high quality hygrometer. It is a necessary tool to insure that you are building at the proper humidity.

Josh
Author:  Colin North [ Sun Apr 28, 2013 7:01 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
I have a bit of the same problem, partly, I think, because the workshop us very well insulated. It's not a problem when I'm out of it, but my sweat/breathing makes the humidity go up. Then the dehumidifier cuts in, plus my body heat and it can get pretty warm at the end of the day,
At least the workshop has a vapor barrier, floor, walls and roof, so that keeps out the humidity and the dehumidifier it not running just if it's damp outside. I can come home after a month away in a Scottish "summer" and only empty a few pints of water from the reservoir.
Is it possible to put a vapor barrier round the room to keep humidity at bay, so he dehumidifier has less work to do?
Author:  WaddyThomson [ Sun Apr 28, 2013 9:25 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
AC is the only way I know of. Before I got my AC put in, my shop was in the 90's all day while I was working. But it was a dry heat! laughing6-hehe I'm sure a good window unit would work fine. I, however, was not allowed to use a window unit, so I put in a mini split system, which was a dual mode system, so it heats in the winter.
Author:  John Killin [ Mon Apr 29, 2013 8:31 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
Thanks for the replies. I was hoping for some sort of simple solution. I guess I'll start looking for some sort of AC system to combat the heat. I might just try and make something to vent the heat from the dehumidifier out the window. If it looks good, I might get approval to use it. laughing6-hehe

We've started using the AC and the humidity is hanging at right around 55% inside.
Author:  dberkowitz [ Tue Apr 30, 2013 9:36 am ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
John, if you're using one of the typical home 50pt units (Emmerson, Hampton Bay, etc) these are particularly inefficient units that draw a lot of power and generate a lot of heat. A better solution is the Thermastor Santa Fe, with the condensate pump. It pulls 100pts/day, drawing less amps than one of the Hampton Bay units and generating a lot less heat. It won't resolve the need for the AC, but it will give you better control and less heat.
Author:  grumpy [ Tue Apr 30, 2013 2:43 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
How about a combination dehumidifier/air-conditioner? The portable type that looks much like a regular dehumidifier; it requires a small vent to exhaust hot air outside, but that's easily done.

Anyone have and use one of these? My old dehumidifier died at the end of last summer, and I will be needing something soon enough, and these look interesting...

The Thermastor Santa Fe looks like a killer unit, but is over $1500? Really? Also would be overkill for most of us, methinks. Me, for sure, as I only need to pull a gallon a day on the worst days here.
Author:  bobgramann [ Tue Apr 30, 2013 3:37 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
I read a couple of reviews on the Santa Fe where it was great until it died at 3 years and 4.5 years. According to one of the reviews, the only service available was at the factory and they had a backlog. I talked to a guy at Thermastor. He said that while the unit was assembled in the US, some of the parts were Chinese made because they were otherwise unavailable. (All of those dehumidifiers that we have been buying in the big box stores here are made by one of a very few Chinese factories--they crimp dissimilar metal parts together in the "sealed unit" so that the coolant leaks out when they corrode.) I concluded that I was better off buying a $200 unit every year or two than paying $1500 for up to 5 years of dehumification. The last one I bought (a GE), came from Walmart where I also bought the 3 year extended warranty for $30. That warranty just paid off 15 months into the life of the unit. I haven't found a good answer to the problem yet. I would expect the same kind of problems with the small portable air conditioners. If I wanted to work (instead of build guitars), I know a business I could go into that's wide open right now.
Author:  WaddyThomson [ Tue Apr 30, 2013 4:34 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
I had one of those and it was pretty much useless. If you are using it to dehumidify, you need to let it vent inside. More heat than a standard humidifier. It did cool some, but not very efficient. It's for sale, want it?
Author:  John Killin [ Tue Apr 30, 2013 4:44 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
WaddyThomson wrote:
I had one of those and it was pretty much useless. If you are using it to dehumidify, you need to let it vent inside. More heat than a standard humidifier. It did cool some, but not very efficient.


Waddy,

Do you know if you vent the dehumidifier outside, if that would work and cut down on the heat?

John
Author:  bobgramann [ Tue Apr 30, 2013 4:53 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
If you vent the dehumidifier outside, it has to draw in air from outside to replace the vented air. That outside air has moisture (or you wouldn't need the dehumidifier--you could just open the window) and thus rehumidifies the the room you just tried to dry. If air conditioning alone to the desired temperature isn't enough to drop the humidity to your target level, you'll have to dehumidify and air condition the room. If you have to add an air conditioner, the smaller it is, the longer it will have to run to get the temperature down, and the drier it will make the air. One that is large enough that it barely has to run to keep the room cool won't remove much moisture.
Author:  WaddyThomson [ Tue Apr 30, 2013 4:56 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
That's what I was saying(for the reason Bob posted). It does not really work as dehumidifier very well unless you leave it vented inside. That, however, keeps it from cooling. All in all, not worth the money.
Author:  joe white [ Tue Apr 30, 2013 11:00 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
We bought one of the Sante Fe units for our 2400 sf basement. I ran two of the big box dehumidifiers 24/7 and couldn't move the RH below 60%. Put the Sante Fe in the basement and in 24 hours I was at 50% and it easily maintains it without running constantly. Didn't really add heat but that is a big area.

For my shop I have a window unit permanently mounted and it keeps the RH at or below 50% with a little help from a small dehumidifier that runs overnight while the air is off. The shop room is 24x25 with cement floor and 11 foot ceiling. I keep the temp at about 73.
Author:  dberkowitz [ Wed May 01, 2013 7:53 am ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
I've had my Santa Fe since 2002, without a problem. I did have to replace the condensate pump last year, but in all honesty, I think it was because of fine dust that created crud in the reservoir that eventually gummed up the works. And it has to run because I'm in an old carriage house built in the late 1800's that has no vapor barrier whatsoever -- not even on the roof, and with exposed brick walls, it leaks like a sieve in an area that is essentially 1600sq/ft, even though I only have half of it (conjoined HVAC). Worth every penny.

Grumpy, depending upon your shop size and conditions, it may not be overkill. If you're in California where it's generally dry, and you have a modest space that's well insulated and sealed, perhaps. But here in DC where the summers are 95-105 and 70-80% humidity, a small unit won't cut it. Furthermore, the cost of running the home units is more per pint than me running the Santa Fe Classic as it draws less power (typically 6A for the typical 50pt unit, and 6.4A for the Santa Fe at 110pts). The smaller Santa Fe units draw 74pts @ 5.4A, so 50% more capacity at .2A less draw. So at .15/kwh, and a 120 day season, that's a $31.10 savings per season versus the standard home dehumidifier.
Author:  grumpy [ Wed May 01, 2013 9:23 am ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
Yeah, I knew that you were in a wet location and building, so the Santa Fe makes sense for you; what I was saying is that it likely is overkill for most of us. Overkill for me, for sure. At just under 10 cents/kwh, my savings by your calculations would be roughly $20/year. It would have to run 65 years to make up for the extra $1300 in purchase price. In your case, you likely would wear out a regular dehumidifier or two each year, so again, it makes sense. I went 12 or 13 years with a cheap 25 pint unit! My shop is sealed so tight that the door can't be slammed closed, no matter how hard you try to swing it, unless another door is slightly opened(no open-able windows).

Back to the combo units, I hadn't considered that the exhausted air gets replaced by damp air, but that would also occur with a window AC unit.

If not for the dehumidifier, my shop would never reach 80°F, and as it is, it only rarely gets above 80. No AC. But as I get older, I'm finding myself less tolerant of working in Ye Olde Sweatshop, so I'm looking at adding at least a small window AC unit if not a portable one. Looks like I'll still need to buy another dehumidifier also...
Author:  Dave Livermore [ Wed May 01, 2013 3:04 pm ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
Heat is an issue and a by-product.
It would be for and A/C, Dehumidifier or a fridge.
They all have the same exact compressor and evaporator.

So, save yourself the headache, forget the dehumidifier and just put a beer fridge in your shop.
Enjoy the benefit of cold beer and a dry work environment.

enjoy

Dave
Author:  grumpy [ Thu May 02, 2013 9:10 am ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
If only it worked that way, Dave.... ;)
Author:  John Killin [ Thu May 02, 2013 9:48 am ]
Post subject:  Re: Dealing With Heat From a Dehimidfier
John Killin wrote:
I need to justify the dehumidifier purchase. I feel like that guy who bought a beer fridge and after he gets it home and talks up the pluses of having such a thing, realizes his keg system won’t fit in (not that I have ever been that guy). laughing6-hehe


Hmmmmm. I may already own the solution. laughing6-hehe laughing6-hehe laughing6-hehe
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