Venting my fish room.

[BrettDS]

I recently set up a small fish room in a closet off of my garage. Given that it's such a small space with no ventilation, the humidity, heat, and CO2 tend to build up quickly.

I'm thinking that I have a few options for ventilation:

I could run a duct or two through the garage to the outside and pull air in from the outside and allow it to vent out into the garage, or out through another duct to the outside. While this seems like a good option on paper, I live in Florida and during the summer it can be in the mid to upper 90's with 80% humidity outside, which, frankly, would probably wind up making the fish room hotter and wouldn't help at all with humidity.

The easiest option might be to just vent to and from the garage. The garage stays in the low 80's, so that's not bad for temp, but the humidity is also pretty high in there. Plus I'm not super fond of venting the salty humidity to the garage as I'm afraid it would cause tools and other metal to corrode.

Finally I considered either venting to and from the house, or from the house and to the garage or outside. I could open a hole or two in the wall between the fish room and the house and pull in the nice cool, low humidity air conditioned air from the house. I'm not sure that venting back into the house makes much sense though because I don't know that I really want to add the humidity or the salt to the house. I'm thinking that maybe pulling air from the house and then venting to the garage or the outside might be the best option. As I said above, I'd rather not vent into the garage, so I'd probably just run a duct to the outside for the exhaust air.

Of course, I don't want to send all of my air conditioned air outside and see my power bill spike, so I wouldn't want to move a lot of air. Additionally, the wall between the garage and the outside is cinder block, so making a big hole for a vent would be possible, but not fun. I'm thinking that I might just get a 3 inch duct fan (or maybe even a bilge vent fan as it's designed for corrosive salty air) to pull air out of the fish room and reduce the duct to one or maybe two inches where it goes through the cinder block. Then I'll install a small vent in the wall between the fish room and the house to allow the cool air to enter the room.

The fish room is quite small (about 106 cubic feet) so even if I'm only moving 20 or 30 cfm through the one inch hole I'll still be completely changing out the air in that room every 4 or 5 minutes, plus it will not be sending too much of my air conditioned air outside.

Any thoughts on this or options that I'm missing?

 

[cdjim]

Not a pro by any means but seams to me a bathroom vent out through you attic would be much easier than going through a block wall

 

[cdjim]

Allow it to pull in air from garrage and save your ac even

 

[BrettDS]

Garage is on the first floor and the attic is above the third floor... Going up to the attic would definitely be harder than going through the wall

Pulling air from the garage is a possibility, but it's still pretty warm and humid in there, and given that any air I pull out of the garage would be replaced by hot humid outside air I suspect it would just get worse as the system ran.

 

[cdjim]

Second floor does make it a challenge.

 

[BrettDS]

So I had another thought this morning. I wonder about just getting a dehumidifier or portable AC.

I worry about the dehumidifier adding too much heat to the room, since it's already pretty warm. I also worry about the portable AC being too large for a 100 cubic foot room and short cycling so it doesn't pull out enough humidity. Additionally, in the spring, fall, and winter the temp won't be very high, so the portable AC might not run at all so it wouldn't pull out any humidity. I'm also concerned about the additional power draw from either unit, but taking conditioned air from the house would cause my central air to run more often and take additional power as well, so that may be a wash.

Ideally I might have a dehumidifier for the spring, fall, and winter and a portable AC for the summer, but I'd rather not have to buy and maintain two devices. I also worry about how the corrosive salty air will affect the coils on the units.

Does anyone have any experience running a dehumidifier and/or a small portable AC in a small fish room?

 

[BrandonFlorida]

So I had another thought this morning. I wonder about just getting a dehumidifier or portable AC.

I worry about the dehumidifier adding too much heat to the room, since it's already pretty warm. I also worry about the portable AC being too large for a 100 cubic foot room and short cycling so it doesn't pull out enough humidity. Additionally, in the spring, fall, and winter the temp won't be very high, so the portable AC might not run at all so it wouldn't pull out any humidity. I'm also concerned about the additional power draw from either unit, but taking conditioned air from the house would cause my central air to run more often and take additional power as well, so that may be a wash.

Ideally I might have a dehumidifier for the spring, fall, and winter and a portable AC for the summer, but I'd rather not have to buy and maintain two devices. I also worry about how the corrosive salty air will affect the coils on the units.

Does anyone have any experience running a dehumidifier and/or a small portable AC in a small fish room?

I built my sump room and added an ac vent, but that was only because someone put a vent in my closet, which was a very small on at that.

Can you install a closet type door and a fan in that room? Or does it have to be sealed off?

 

[Windy2]

Its pretty easy to install a louver vent in the wall or door. Then a bath fan vented to the house would keep it well turned over. You can put the fan on a timer rather than run it all the time.

 

[BrettDS]

I built my sump room and added an ac vent, but that was only because someone put a vent in my closet, which was a very small on at that.

Can you install a closet type door and a fan in that room? Or does it have to be sealed off?

It's kind of a unique room because the door is off of the garage... and being in florida, you know how hot and humid the summers are. Venting through the door probably won't be terribly effective since the garage is quite hot and humid too. (Although for now, I've been been leaving the door open to get by, but it's staying at about 80% humidity and I'm sure that's not good for the equipment and such in there)

It shares a wall with a hallway, so it would definitely be possible to put a vent or two in between the closet and that inside hallway, but like I said above I'm not really fond of introducing the humid air back into the house. It may still be an option though. For now I'm still considering the portable AC or dehumidifier option.

 

[BrettDS]

Well, I made a quick stop at home depot and bought an 8000 BTU portable AC. It said it can be run as an air conditioner or a dehumidifier, so it sounded like it may be the perfect solution. I got it out to the car and as I was loading it I noticed that it said it was ideal for a 200 square foot room. Assuming an 8 foot ceiling, that's 1600 cubic feet. My room is 106 cubic feet, so I just can't see it working well. It will short cycle and not dehumidify the air at all. I debated just running it in dehumidify mode all the time, but it seemed silly to pay nearly double the price of just a dehumidifier, so I took it back into home depot and returned it and bought a dehumidifier instead.

I figure the dehumidifier will be the easiest thing to just try and see how it works... it won't require making any holes in the wall or venting to the outside. If it works well I'll want to install a drain hose, but for now I can just let the water collect in it's collection thingie. It's not gonna help with the temp at all (actually, I'm afraid it's going to raise the temp too much) or the CO2 level, but I've already got the intake of my skimmer run to the outside, so hopefully that won't be too much of a problem.

I'll let it run for a while and see how we do.

 

[BrettDS]

I got the dehumidifier up and running and the good news is that it was able to take the humidity down from 78 to 45... the bad news is that it brought the temp up from 83 to 97 in the process. I'm thinking that it just ran a pretty long cycle to pull down the humidity by that much, so I'm hoping that as things stabilize it will cycle on and off more and hopefully the temp will come down to a more reasonable level. I suppose I could still open a vent between the closet and the house... with the dehumidifier in the fish room I won't have to worry about excess humidity going back into the house.

 

[HaiD888]

I think you should have the opening to the outside with the fan that have reversible flow, and the opening to the house that can open and close. This way, you can control the air in and out of the room depend on the condition of the house, the room, and the outside.

 

[Shawn O]

Seems like the best option would be to draw air from the house->fish room->outside.
Will use some AC but only during the hot months, will be pulling in dry, cool air from the house and pumping the humidity from the fish room to the outside. Fish room stays cooler/less humid and the house does not get the humidity from the fish room. Running an AC or dehumidifier in the fish room will likely cost you more than what extra electricity the house AC will use. This could probably be run by a temp/humidity switch in the fish room to turn on the vent fan only when needed. Just my $0.02

 

[BrandonFlorida]

It's kind of a unique room because the door is off of the garage... and being in florida, you know how hot and humid the summers are. Venting through the door probably won't be terribly effective since the garage is quite hot and humid too. (Although for now, I've been been leaving the door open to get by, but it's staying at about 80% humidity and I'm sure that's not good for the equipment and such in there)

It shares a wall with a hallway, so it would definitely be possible to put a vent or two in between the closet and that inside hallway, but like I said above I'm not really fond of introducing the humid air back into the house. It may still be an option though. For now I'm still considering the portable AC or dehumidifier option.

Isnt the room actually in the house and under ac? Can you post a picture of this room? Im pretty sure you have before I just cant remember too well..

 

[BrettDS]

Venting my fish room.

Lol... When I originally posted this I intended to include a picture, but apparently I forgot. It is not air conditioned though. It is under the house, but the only opening is the door that goes into the garage. Like I said, though, I can put a vent through the wall into the house.

And I'm thinking that like Shawn said, moving air from the house, through the fish room and to the outside will be best. I've been playing with the dehumidifier a bit and it's just putting too much heat into that small space as it dehumidifies.

 

[salty joe]

Would it be possible to figure out a way to put the dehumidifier in the garage or outside and connect the dehumidifier to the fishroom with ductwork?

 

[Shawn O]

The air inside the house is already cool, de-humidified and paid for. The air in the house needs to be vented to the outside, anyway, to remove the nasties that come with enclosing a space where there are people and appliances.

 

[BrettDS]

Would it be possible to figure out a way to put the dehumidifier in the garage or outside and connect the dehumidifier to the fishroom with ductwork?

Frankly, that's an air conditioner. An air conditioner has a cold side and a hot side... The cold side cools the room and the hot side goes outside (or is vented to the outside on the portable systems).

A dehumidifier is the same thing, but the sides aren't separated... The air goes over the cold coils to cause the water to condense and be dehumidifier, then it goes over the hot coils. The advantage being that it doesn't require an outdid se vent, but The problem is that it's not 100% efficient and the wasted energy generates heat, so the air is heated more than its cooled and the dehumidifier puts out warm dehumidifier air.

 

[salty joe]

Oh, I thought the heat from a dehumidifier was from the motor-did not realize the air was being actively warmed after passing the cooling coil. In that case I agree with Shawn O. You could hook a small bath fan to either a thermostat or a humidistat for control.

 

[BrettDS]

This morning I ran to Home Depot and picked up a cheap ($14) bathroom vent fan that promises to move 50CFM. I installed it moving air out of the fish room into the garage for now. If it works I'll probably try to run it outside, but I didn't want to bother running a duct and all if it's not going to work. I also opened a vent hole in the wall between the house and the fish room to allow cool dehumidified air in. I shut the door and I'll let it run for a while and see how we do. When I shut the door my meter was showing a temp of 82.1 and 78% humidity.