Dehumidifier in a Fish Room

[Myka]

Do you have central AC? Or a high efficiency furnace that you could leave the fan on all the time without costing a fortune?

Either option will produce positive air pressure in the room provided you make sure the room is sealed well (check the door in particular, maybe lay a towel on the floor to block the air under the door). Then drill a 1" hole in the wall to the outside at floor level, shove a 1" PVC pipe in there and put mesh on the end so that bugs don't get in. Humid air sinks, the positive air pressure will push air out the vent. No additional electricity used.

An HRV is the best long-term option though.

[MarkoD]

well the dehumidifier fills up with water after about 12 hours (i now have it draining directly into a drain. so it must be removing moisture from the air. (a regular fan wouldnt condense and dispense water from the air)

The house has central air but since the fish room is in the same room as the furnace, there are no air outlets in there

[Rogue951]

my room is small (11ftX11) I use a portable air conditioner in the summer.
It's a single exhaust so it's using the air inside to cool itself, evap the moisture and exhaust outside.
When it's cool enough I just have a 6 inch exhaust fan in the top corner of my room, spits air right outside.

Noticed a huge increase in evap when I added the exhaust fan so I'd say it made a difference in humidity.

[sphelps]

Originally Posted by MarkoD

well the dehumidifier fills up with water after about 12 hours (i now have it draining directly into a drain. so it must be removing moisture from the air. (a regular fan wouldnt condense and dispense water from the air

Correct but why remove moisture from air you're pumping outside? The dehumidifier by itself will certainly lower humidity in the room but if you're taking all the air that it is exhausting out of it and sending it outside the dehumidifier is not doing anything more for you than a regular fan would. Yes you're condensing water but unless your goal is to make water you're not gaining anything from using the dehumidifier.

Is this clear? I'm not sure if I'm explaining this well, maybe others can help.

[MarkoD]

no i totally understand. because its not replacing moist air with the dry air, its just pulling more moisture from the rest of the house.

i just dont think theres any way for me to use this. the heat it produces raises tank temp to 81.5.

looks like ill just have to get an AC unit for the fish room.

[sphelps]

But it's not pulling "more moisture" than just a fan alone would. Unless you agree with that statement you don't completely understand.

If heat isn't an issue without the dehumidifier and you have a way of exhausting air outside from the fish room I'd suggest just using an exhaust fan to control humidity. By venting air outside you're exchanging air, new dry air will enter the room as needed from the rest of your house. No need for an HRV, it really won't help in summer months, only winter and more than likely humidity isn't much of a concern in the winter.

[MarkoD]

my issue is that that rest of the house is about 50% humidity. and id like to get my fish room down to 35% because its in the same room as the furnace,boiler, electrical panel.

a fan will just keep it at 50% like the rest of the house, right?

[sphelps]

Originally Posted by MarkoD

my issue is that that rest of the house is about 50% humidity. and id like to get my fish room down to 35% because its in the same room as the furnace,boiler, electrical panel.

a fan will just keep it at 50% like the rest of the house, right?

Yeah in theory but depends if we're talking about real humidity or relative humidity. We measure relative humidity which is a percentage of how much moisture is in the air relative to how much moisture the air can hold at it's temperature. So if air is warmer in the fish room which is typically the case due to equipment then your relative humidity could be lower than the rest of your house. For example 50% humidity @ 20°C is the same amount of moisture as 35% humidity @ 25.9°C

Now if you cool the air with an AC unit you will remove moisture but relative humidity may still stay the same or even increase.

50% relative humility is just fine for your house hold equipment. What you need to be concerned about is if anything the air in the room comes in contact with is cold enough to form condensation but @ 50% relative you'll need a 10°C temperature difference.

[The Guy]

Originally Posted by sphelps

But it's not pulling "more moisture" than just a fan alone would. Unless you agree with that statement you don't completely understand.

If heat isn't an issue without the dehumidifier and you have a way of exhausting air outside from the fish room I'd suggest just using an exhaust fan to control humidity. By venting air outside you're exchanging air, new dry air will enter the room as needed from the rest of your house. No need for an HRV, it really won't help in summer months, only winter and more than likely humidity isn't much of a concern in the winter.

Totally agree with you. I run a 500 CFM exhaust fan, works great and the room air is replaced by the air conditioned area in my home.

[mark]

Originally Posted by MarkoD

The house has central air but since the fish room is in the same room as the furnace, there are no air outlets in there

Outlet won't help but if you drew moist air from the room (inlet on your return air) it would condense on the A coil (just like your dehumidifier).