Yet another HVAC question...

cptlo

cptlo

Pursuit Driver
I may have asked similar questions last year...I can't remember (I don't think I did but I'm getting old and forgetful...).

What is the best way to handle high humidity inside my condo? Right now the little weather station thingy is showing that it is 72% humidity in here. The AC system does a decent job of cooling and can keep it around 70 all day but the humidity is too high. Condo is in a high-rise building and the AC system uses chilled water from the building for cooling (my limited understanding is it opens valves to allow the chilled water to pass over coils and then blows air over the coils...granted this could be completely wrong). The AC unit within my condo is only 2 years old.

I've asked the AC vendor that works in the building if there is any sort of dehumidifier add-on to the AC unit but the answer was no. I have a portable dehumidifier that actually does a pretty good job of getting the humidity down to 45-50% but it has 2 problems: 1) the hot air exhaust heats the condo and the AC doesn't seem to be able to compensate while the dehumidifier is running; and 2) it's annoying having to empty the water tank 2-3 times a day.

So, given all that, are there any alternative solutions or things I should do that would help lower the humidity and keep it lower?

Thanks in advance!!
 
Sadly...
You have a chilled water loop system... and there is not much you can do with it... other than keep a clean filter in it and 'bribe' the maintenance guy to thoroughly clean the innards of the 'air handler' gadget in the utility closet.

The portable dehum is probably the best solution... and they come with a built in pump and a plastic tube that can go to a sink or tub.
I would put the dehum unit close to a return air vent... so the system can swallow some of the heat the dehum makes.
Some experimentation with where the dehum unit is placed... might produce better/worse results... and give you an idea of the better location.

Now if you had your own separate system... we could do some modifications to it... to improve the 'latent' (dehum) capacity.
 
Actually, the system runs chilled water through a coil and your unit blows air over that coil.

To dehumidify with air conditioning, you need two things:

1) For the cooling coil to be cold enough that it condenses the humidity in the room air onto the coil, where it runs off to a drain.

2) Sufficient run time for this to occur

It sounds like you have enough run time, but you might not have the T/D (total difference) in temperature between the return air and the cooling coil to properly dehumidify. You might ask the building engineer if he can make the water colder so you can get a colder coil, but I suspect that the answer will be no.

Check to make sure that you don't have an outside air intake that is open. Often, these are required by code, even when not really necessary. If you do, you're pulling in humid outside air. It can probably be closed, or at least dampened down some.

You can sometimes remove more humidity by "over-cooling". That means turning the thermostat lower and making the system run longer.

There absolutely is such a thing as duct mounted dehumidifiers. But they have to be professionally installed, and you might not have the space for it.

Be sure to run exhaust fans when cooking or bathing, but no more than needed because they will tend to pull outside air into the space. Prevent all the humidity you can so you don't have to deal with it. That includes farting less.

As a last resort...there is such a thing called desiccant humidification. It uses silica gel (you know the little packets of stuff sometimes packed with electronics?) to absorb the moisture. But, the silica gel must be replaced or recharged by drying it out with heat. This could be an expensive and bothersome method.
 
Thanks guys. I appreciate the info. Sometimes I wonder if buying this high-rise condo was the right move. I like it but things like this are really annoying.

I took my little weather station thingy into the hallway and downstairs to the building lobby and the humidity level at both locations was still around 70%. Isn't it true that humidity that high can cause mold growth? It seems like the building system would be setup to not allow it to get that high consistently.

Guard Dad said:
That includes farting less.
Click to expand...

Not sure that's gonna work. :D
 
cptlo306 said:
Thanks guys. I appreciate the info. Sometimes I wonder if buying this high-rise condo was the right move. I like it but things like this are really annoying.

I took my little weather station thingy into the hallway and downstairs to the building lobby and the humidity level at both locations was still around 70%. Isn't it true that humidity that high can cause mold growth? It seems like the building system would be setup to not allow it to get that high consistently.



Not sure that's gonna work. :D
Click to expand...
Yes, mold thrives in humidity that high.
 
The only thing I can offer is that they make portable dehumidifiers with a pump that can pump the water into a sink or tub through a small hose. I have one at the cabin so I can run the dehumidifier while I'm here in Hiram and it works great.

Can't help you with the heat problem though.
 
cptlo306 said:
I've asked the AC vendor that works in the building if there is any sort of dehumidifier add-on to the AC unit but the answer was no. I have a portable dehumidifier that actually does a pretty good job of getting the humidity down to 45-50% but it has 2 problems: 1) the hot air exhaust heats the condo and the AC doesn't seem to be able to compensate while the dehumidifier is running; and 2) it's annoying having to empty the water tank 2-3 times a day.
Click to expand...

Yea condensing that much water from the air will release large amounts of heat. However, once you get the humidity down, I would expect that it would have to run much less and the standard A/C could keep up. Are you getting three buckets a day continuously?
 
The Sound Guy said:
Yea condensing that much water from the air will release large amounts of heat. However, once you get the humidity down, I would expect that it would have to run much less and the standard A/C could keep up. Are you getting three buckets a day continuously?
Click to expand...
The problem is...being that the entire building apparently has high humidity, he might be fighting a losing battle. The building management needs to address the issue.
 
lotstodo said:
The only thing I can offer is that they make portable dehumidifiers with a pump that can pump the water into a sink or tub through a small hose. I have one at the cabin so I can run the dehumidifier while I'm here in Hiram and it works great.

Can't help you with the heat problem though.
Click to expand...

I was looking at them online last night. There is a version of the one I already have with a pump so I may get that one.


The Sound Guy said:
Yea condensing that much water from the air will release large amounts of heat. However, once you get the humidity down, I would expect that it would have to run much less and the standard A/C could keep up. Are you getting three buckets a day continuously?
Click to expand...

Yeah, when it gets down from the initial 70% or so, it does run less. I usually have to empty it twice a day when it's running after the initial couple of days.


Guard Dad said:
The problem is...being that the entire building apparently has high humidity, he might be fighting a losing battle. The building management needs to address the issue.
Click to expand...

I've got a call into them.
 
Guard Dad said:
The problem is...being that the entire building apparently has high humidity, he might be fighting a losing battle. The building management needs to address the issue.
Click to expand...

Sadly... it costs building management more $$$...
To run the chiller at a level that would circulate cold enough water...
To properly de-hum your condo.

Not saying anything...
However I would never allow a management company to have that much control over my life...
NEVER!
 
JawJa said:
Sadly... it costs building management more $$$...
To run the chiller at a level that would circulate cold enough water...
To properly de-hum your condo.

Not saying anything...
However I would never allow a management company to have that much control over my life...
NEVER!
Click to expand...
His cat has control over his life too.
 
There are many advantages in living in a condo and I might consider it myself one day. However the building is only as good as the management. This is your home but it is a business to them so you have to approach them with that mind set. If they can save money by piece milling utilities and systems often they will. I do not know your situation and they may just need time to get the system right but do not let them give you excuse after excuse and drag the issue out until it effects your quality of life or worse your health. Again you have a contract and the owners end should be to maintain the property in reasonable/safe living conditions. Your end is to pay your share and follow the rules. I hope it works out with little effort but if you have to be a little bit of a hard ass then do it. Hope it works out for you.
 
I have never known a water chilled building that was comfortable in the summer. It's highly likely that the system simply cannot produce cold enough air in your condo to dehumidify without freezing out people on another floor.

Just a couple of thoughts though, if you have your own air handler, check the filter. Also make sure all of the vents are completely open. This will make sure you are at least getting all the cool available to you, and then go with a dehumidifier that pumps into a sink. Yeah, it's the Management's problem now, but the likelihood of actually getting it fixed is beyond slim.
 
This is probably not feasible, but just a thought.

You could use one of those portable air conditioners...you know, those upright types that exhaust the hot air through a small duct. But you'd have to have a means of exhausting that duct to the outside or to a building exhaust duct. You'd want a smaller one so you'd get more run time, and it would pull out considerable humidity. A portion of that would be offset because exhausting the hot air to the outside would put your space into a lower pressure and pull air in from hallways, etc. But I think you'd still get a net reduction in humidity. And it would use some electricity.

Circling back, though, the first thing I would do is have your HVAC guy check to see if you have a fresh air intake that can be closed or pinched down.
 
I'm no HVAC expert, but I would check all of the vents (clothes drier, bathrooms and kitchen) for proper function. Determine if the kitchen vents air to the outside, and if it does, run the vent whenever cooking as well as when you run the dishwasher. Always run the bath vent when bathing. Service the drier vent for lint buildup and therefore make it easier to exhaust moist air. Make sure the air handler is getting rid of all the condensation.

Nextly(?), do you have multiple air returns, or one large one at the air handler? If it is one large, I would think that someone makes a cabinet dehumidifier unit that fits in front of that opening and takes out 30 pints of water per day.

Lastly, it's an exercise in logic. You have too much humidity. Eliminate the water mechanically or contain it by eliminating/controlling the source, (as GD suggested, find that fresh air inlet). I would log humidity levels on a 10 minute basis, if you can, along with the outdoor weather and look for a pattern. Determine first why the humidity is that high,,, 72% is like breathing mud!!!!!
 
Update: I've been playing phone tag with the building manager but they must have done something. I got home a few minutes ago to 55% humidity and a cool 68 degrees. I'd prefer even lower humidity but it's definitely an improvement.

Note: that is without running the dehumidifier for the last 2 days.
 
cptlo306 said:
Update: I've been playing phone tag with the building manager but they must have done something. I got home a few minutes ago to 55% humidity and a cool 68 degrees. I'd prefer even lower humidity but it's definitely an improvement.

Note: that is without running the dehumidifier for the last 2 days.
Click to expand...
Best to stay under 50%, but that's definitely much better than before.

Betcha they shut down the fresh air intake.
 
That's good... 55% is about right for the south in summer.

I was thinking you might want to sell your place before the building is overtaken with mold and you can't sell when you were reporting a 70% level. :(

I could always tell when the chiller was not working in the hotel. Once our humidity was over 70%, something needed to be corrected. Either get the water temperature lower or find out what was not working, because it was about to get uncomfortable.

The stupid engineer would claim everything was fine... it never failed that evening as the hotel checked in full and none of the guests could get the rooms comfortably cool due to the high humidity and staleness of the room. 79 degrees with 75% humidity is miserable. I was so happy when they found a new engineer. Guest scores drop when guests can't make the room the temp they want it!
 
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