Dehumidifier in a Fish Room
 

so i put a dehumidifier into my fish room and it does a great job lowering the humidity. but it puts out a lot of heat and was heating up the room and tank

so i decided to disconnect the bathroom style fan and vent the dehumidifier all the way outside. but still for some reason it seems to be heating the room a lot. (8 feet of the exhaust pipe is not insulated and probably releasing heat back into the room)

anyone have any suggestions?

I installed an HRV.

Marko, I've never used one, but 2 thoughts

Can the unit push air the 8 feet, or does it need a booster fan ?
Does all the heat created go out the pipe ?

As I said, I've never used one

The total pipe length is about. 40 feet. And it pushes great. Warm air gets out. It's Just the first 8 feet that are not indulated and the pipe heats up

seems you've figured it already, insulate the pipe though HRV are nice

I guess my question is, if I'm venting the warm dry exhaust outside, am I actually lowering the humidity in my fish room?

Is the water still collecting in the reservoir? Ignore my question, I misinterpreted yours

That's a pretty must the most inefficient way of doing it but yes you're lowering humidity however not anymore than removing the dehumidifier and just using the fan would. Whatever goes through the dehumidifier goes outside so why use the dehumidifier which is only heating up the room which will actually increase humidify as warm air holds more moisture. The only difference is you're removing the water first and pumping the warmer and dryer air outside, so unless your goal is to waste energy you're not accomplishing anything more with the dehumidifier. Just use a fan on a humidistat to control the rooms humidity, otherwise you could also use an air conditioner to do the same thing as the dehumidifier but cool the room at the same time which will lower humidity further.

no, not really because you are putting the dry air outside, so you are basicelly removing humidity from the outside air since the dry air it not going inside your home.

That would be like exhausting the cool air from an AC unit outside the house...no point really and a waste of energy.

Mine also create quite a bit of heat but since it's my basement then it's not too bad.

You could be using a portable AC unit instead. These can remove humidity nicely and put out cold air at the same time you would just need to put the exhaust outside, so the hot air would go outside and the cold dry air would cool down your fish room.

I use both, I have central AC and a dehumidifier in the basement so my home is cool and dry.

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. :)

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 :(

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.

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.

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.

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.

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?

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.

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.

I don't really know the specifics. The room is naturally cool (3 exterior concrete walls and interior wall is insulated) and there are no windows. Running LEDs even as room lights to avoid introducing heat

My main goal is to keep the humidity in the room as low as possible to lower the risk of anything being effected by it.

In my old house. I noticed that drawer handles had started feeling rough (like sand paper) even tho they were about 20 feet from the tank.

Anyone know if its possible to disable the heating coil in a dehumidifier?

Would it not be more economical and practical to build some kind of enclosure around your tank equipment to separate it from your mechanical room? The enclosure could be vented separately and you eliminate all your issues and concerns. Keeping the whole room cold will only cut back on evaporation but won't necessarily make much of a difference to protect your house.

Exposed cold water pipes and your water meter are probably the biggest targets, every fish room I've seen that shares space with a mech room had corroded pipes. Next is the furnace ducting. But I think the issues relates to more to the type of evaporation, as salt seems to get evaporated as well it will cause damage much faster. Just sealing the room up and keeping it cold may not make a difference at all, better to have air exchanged. Your house air at 50% humidly won't damage anything, it's circulating through the furnace anyway and would damage other things in your house before your electrical panel or other mechanical room equipment.

Keeping it separate is best option but IMO the next best thing is general circulation. Keep the air exchanged reducing the amount of salt in the air, like I mentioned before this is done with a simple exhaust fan and humidistat.

I think typically the heating is the side effect from cooling process. Just like an ac unit the process involved creates heat during the compressing stage. This heat has to go somewhere and for AC units it's exhausted outside, for dehumidifiers it's used to reheat the air. The air gets hotter due to the inefficiency of the process.

That is 100% correct.

Thanks for the reply. I had an exhaust fan setup in there(which is where the duct that goes outside is from) but it didn't seem to do much. Maybe I just need a more powerful fan

Anyone know where in edmonton I can get a 6" exhaust fan? A bathroom exhaust fan obviously won't cut it

You could try Soper's Supply, they deal with all sorts of exhaust fans for both residential and commercial.

Thanks. I bought a 220 Cfm fan from Home Depot. Doesn't seem like much.

Should this be enought? I had a 70cfm bathroom fan on there before

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).

Pretty sure that's against building code

Depends on the room size, I don't know what the regulation for fish rooms is but indoor "gardens" require the air be adequately exchanged every three minutes. So for a room 10x10x10= 1000cf you need 333cfm.

Becareful with a hi powered exhaust fan in you furnace room. You don't want to put that room into negative pressure, you run the risk of pulling air back down the chimney.

its a high efficiency furnace. theres a sensor in the room actually that'll turn on the furnace on if it causes too much negative pressure

funny how this thread just popped up! with my new open top 160g system running in my condo i decided it was getting kinda humid so i purchased a small dehumidifier from work.. and yea the thing really raises the temp in the room and it fills up with water pretty fast!

pretty sure i'm going to return it and just forget about it.. leave the patio door open and turn on the ceiling fan overnight :p

Marko you still living with your parents ? I can't recall.

If so it would help if people knew that modifying your parents house with something like HRV is prObably not going to happen.

My dehumidifier heats my room like crazy too. Crazy.