Venting Dehumidifier Exhaust?

[Coastie Reefer]

I’ve been setting up a detached fish room (build thread in signature) and I’ve been battling humidity. I now have a dehumidifier that I use and it can maintain 45-50% humidity fairly decent but the issue is the heat it generates. I’m only working with roughly 120 sq ft so the dehumidifier exhaust adds a ton of heat. Today it was 38 degrees outside and 78 inside! Would it be possible for me to duct the exhaust to the exterior, maybe rigging something like a dryer vent?

Advice, experience, and options would be greatly appreciated.

 

[sfin52]

Were are you going to vent the air to.

 

[Coastie Reefer]

Were are you going to vent the air to.

Outside. I was thinking a 4” exhaust pipe just like a dryer uses.

 

[sfin52]

Outside. I was thinking a 4” exhaust pipe just like a dryer uses.

If you do that than you are pushing air out of the house. This will cause air to come in from the out side . I would move the air to adjacent room.

 

[Coastie Reefer]

If you do that than you are pushing air out of the house. This will cause air to come in from the out side . I would move the air to adjacent room.

Well... there is no adjacent room.

 

[cooltowncorals]

I think it’s been done can’t remember who but I’ve heard of people doing that just need to figure out a way to toggle it on and off and some kind of check valve or outside vent that shuts when it’s not running so outside air doesn’t flow back in.

 

[Coastie Reefer]

I think it’s been done can’t remember who but I’ve heard of people doing that just need to figure out a way to toggle it on and off and some kind of check valve or outside vent that shuts when it’s not running so outside air doesn’t flow back in.

A simple dryer exhaust vent is louvered and only opens when air is being pushed through it. It prevents air from back drafting and keeps little critters out too.

 

[ca1ore]

Wouldn’t sending the exhaust air outside rather defeat the purpose of running the dehumidifier (since the hot exhaust air is also the dried air)? Assuming it’s a standard portable unit, that is. I had looked a while back for a ‘split’ unit but could not find one.

 

[Livinlocal]

If you’re going to vent it outside, you may as well just use a normal fan. The air you would be pushing outside, is the dry processed air that you want inside the room to dehumidify the room. They don’t work like an air conditioner, where the exhaust is wasted air.

 

[Livinlocal]

If I were you, I would install a turbine roof vent, and some sort of filtered gable vent. You'll save electricity, and get fresh air inside.

 

[Coastie Reefer]

Wouldn’t sending the exhaust air outside rather defeat the purpose of running the dehumidifier (since the hot exhaust air is also the dried air)? Assuming it’s a standard portable unit, that is. I had looked a while back for a ‘split’ unit but could not find one.

If you’re going to vent it outside, you may as well just use a normal fan. The air you would be pushing outside, is the dry processed air that you want inside the room to dehumidify the room. They don’t work like an air conditioner, where the exhaust is wasted air.

It is a standard portable unit and that's kind of what I was afraid of... I guess I was hoping the heat was more of a byproduct of dehumidifying.

So now I need to figure out a way to mitigate the heat. Back to running the unit on a timer today cycling 30 mins on - 1 hour off. Maybe that will help with heat since it won't run nearly as much as when the unit is set to a particular RH, which is pretty much constantly.

 

[petercl14]

The heat is a byproduct of dehumidifying. It is a heat exchanger. You are removing heat from the unit which causes the cooling coils to get very cold which then causes moisture in the air to condense on them. If you are aiming for a cool house on a hot day you can't get it if you can't exhaust the hot air.
Yes I to am looking for a dehumidifier that will vent the hot air outside the house like an air conditioner. Manufacturers please provide a dehumidifier that vents the hot air outside. Can't see any reason why this cannot be done.

 

[Malcontent]

A portable AC is basically a dehumidifier that exhausts the hot air outside. A dual hose unit won't create negative pressure in the room since it draws outside air to cool the condenser(?).

 

[Paul B]

maybe rigging something like a dryer vent?

Thats what I did. Works great and very cheap.

 

[jda]

Outside air is your friend. Too many make the mistake of thinking that they need to use the fan for a long time to cool down a room, but all that you need to do is exchange the air. In a small room like that, assuming a 8 foot ceiling, there is less than less than 1000 square feet of air... so a 1000 CFM fan needs to run for 1 minute a day to exchange 100% of the air. This is not enough time even if it was 0 degrees outside for your room to cool down much at all. People think that they need to run fans for like 5 hours in the cold winter, but that is just not necessary. This will not only help with the humidity, but also the co2.

 

[snorklr]

depends where you live...if its really humid outside you're not accomplishing much...afraid its time to run the dehumidifier and the a/c unit together, or just resort to exhaust fans and hopefully some filtered intake air so you don't fill the place with pollen

 

[theMeat]

I’ve been setting up a detached fish room (build thread in signature) and I’ve been battling humidity. I now have a dehumidifier that I use and it can maintain 45-50% humidity fairly decent but the issue is the heat it generates. I’m only working with roughly 120 sq ft so the dehumidifier exhaust adds a ton of heat. Today it was 38 degrees outside and 78 inside! Would it be possible for me to duct the exhaust to the exterior, maybe rigging something like a dryer vent?

Advice, experience, and options would be greatly appreciated.

When was house built?

 

[mehaffydr]

Looks like you have a window type AC unit in the wall? That will cool the room and also help dehumidify. You will just need to run the AC on the warmer days.