Large Tank IN a Basement-Ventilation Suggestoin Please oh brethern of the mamoth tank

[capncapo]

Mantis,

Running the fan won't hurt anything to speak of. It may cause your squirrel cage to get some surface rust though IF the paint on it isn't completely covering it.

My biggest concern with doing that would be that you will be taking the basement air and circulating it through the house with no chance of dehumidifying the air until the unit kicks on. You would, in essence, be making the rest of the house as humid as the basement and would need to set your thermostat lower to compensate for the added humidity. It would also most likely increase the evaporation rate of the tank because the air in the basement will become warmer and dryer.

If it were me, I wouldn't do it.

 

[billpa]

capncapo

I have a question for you. I have double returns in all of my rooms in my house (for winter or summer). I guess you call that a high or medium effiecient system as it recirculates either the hot air and cools it or the cold air and warms it. The duct work runs the length of my basement. Half of the basement is framed out as a laundry room where the gas furnace and AC resides. The other half is where my 180g tank is. Ive been running a dehumidifier but it definitely brings the heat up quite a bit. So Im looking to add one or two vents from my return in the basement. Its behind a wall inside of the laundry room. And its the soft ducting...no pipes. What would be the best way to add a vent? Should I add one in the laundry room and the tank room? And would this design eliminate the need to use a dehumidifier down the road (as you said it takes a little while for things to balance out)

Thanks in advance!

billpa

 

[capncapo]

I assume by 'soft ducting" that you are referring to "flex-duct"? Flex duct is the "plastic covered slinky surrounded by insulation covered in plastic.

Or are you talking about the "duct board"? The soft "celotex" looking stuff that resembles a bunch of fiber glued together to form a board.

 

[billpa]

No...its square in shape. Its soft insulation I think...wrapped in the reflective material. Please excuse my ignorance but I know nothing about HVAC. This duct runs 3/4 the lentgh of my basement and then stops. It then looks to go straight up....I think the returns in my rooms are just vents inside of a framed out area. I also have the same soft ductwork for exit from the furnace and the AC. But from that duct, there are metal ducts that are attached and run between joists in my basement and to registers around the house on the first floor. Any ideas?

Thanks!
billpa

 

[billpa]

I did a little bit of searching and it looks like it is made of duct board (possibly fiberglass...have to check). Does this make sense? Also would it be a problem pulling moist air into it because of the possibility that moisture will be trapped inside and creating a place for mold to grow. Perhaps I can trace the duct back to the furnace and see if there is a place for a better connection.

billpa

 

[capncapo]

Billpa,

If it's what I'm thinking of, I may have some bad news for you. Does it remind you somewhat of a soft particle board?

If so, that stuff is not on my list of favorites. With the right tools, that stuff almost installs itself. It's light and extremely easy to work with. I checked into buying the tools to install that stuff. I talked to a local supplier about it and was told that I did not want to use it. I spoke to a friend in the business who works for a company that uses it. He told me that I didn't want to use it. Both told me that it is prone to mold and doesn't hold up well to moisture. That would be my guess as to why you have it mainly being used for your returns.

Make sure that your installation is not using it for some type of sound or thermal insulation. If is not used as insulation ( with tin inside ), I can't say that I would really recommend this modification to you. IF the material that you are using is what I'm thinking of, you could be opening a can of worms by performing this modification.

DO NOT take me at my word on this. It has been a while since I looked into this and the materials may have changed/improved in that time.

I would recommend that you find someone local who can tell you what you have and whether it would create a problem to use it in a high humidity application.

If your particular material will work for this purpose adding a register to it should be a snap. Simply cut a correctly sized hole into it and screw a couple of screws into it. It should be able to support the register with just two screws. If it's too thin, cut a couple pieces of 3/4 inch thick and 2 inches wide wood at least as long as the register is high. Once the hole has been made, put a piece of wood INSIDE the hole and hold it to where the edge of the wood is at the edge of the hole. The wood will be inside the duct and only the edge of the wood should be visible. Put two screws through the duct material and into the wood. That should hold the wood in place. Do that on both sides of the duct opening. Next, place the register in the opening and screw it into place. This will "sandwich" the duct material between the register and the installed pieces of wood. That will hold the register fine.

Before you do anything, make sure you are working with the return side of your unit. Your description almost makes me think that the metal part of your system is the return side.

 

[billpa]

yeah thats what I was afraid of. Im going to research futher to see who makes the duct board. I was researching and saw a few companies that make it with a lining on the inside that prevents moisture from getting trapped inside of the fiberglass. I will look into it.

It makes me wonder. When we first bought our house, we had a piece of our furnace recalled and a guy came out to install an exhaust fan. I dont know how it kicks on (not on all the time) But it basically exhausts outside of the house. I dont know what exactly it is exhausting though. Perhaps I will snap a few photos.

Bummer...I thought I finally figured out how to get it more comfortable down there. I suppose I will just keep running the dehumidifier. Thank god I didnt add a return register down there yet.

Thanks!
billpa

 

[capncapo]

Have someone come out and give you an estimate on replacing it with tin. Or, if you're very handy at all, you may be able to do it yourself. You can buy pre-made sections of duct.

If it's nothing but a straight run from one side to the other, it should not take a pro long to do at all.

It may be possible that you are venting moisture because of the buildup in the ducts. The vent could be running off of a humidistat. It wouldn't surprise me.

 

[capncapo]

Some info for those witth 90% efficient furnaces:

Most furnaces use indoor air to supply the venter blowers ( if they have one ). Furnaces with a standing pilot don't have a venter.

Because these units use inside air in order to exhaust flue gasses, when the furnace runs it is exhausting humidity. Between the air outside being dry in winter and the exausting of flue gasses, it is conceivable that your humidity problem could totally disappear in winter with this mod done. Much depends on how "tight" your home is AND how well it is insulated.

Furnaces with a 90% rating DO NOT use indoor air to supply the venter and therefore will never reduce the humidity in your home. This mod will help you spread humidity throughout your home . The added humidity will allow you to reduce your thermostat setting which, in turn, will decrease tank evaporation rates but you will have to use some other method to exhaust humidity from your home in winter.

 

[hawk66]

You want to open the sheet metal ( provided that it is, in fact, part of the cold air return ). Don't touch the cold air intake.

My n/g furnace is 35 yrs. old. No a/c so not a solution in summer but could help in winter. I have returns upstairs that run to the furnace, tee'd into this ductwork is a 6" pipe to an outside vent. Best as I can tell drawing additional air to the furnace. Is this what you are referring to as the cold air intake. This pipe runs through my proposed fishroom into the return duct. Why is it not a good idea to cut into this to draw from the fishroom? Thanks

 

[capncapo]

First, you'll have to tell me what you mean by "n/g".

 

[billpa]

I think he means natural gas

 

[capncapo]

I thought he meant No Good!

The reason that I told Skippyreef not to cut his is that it is being used to provide "make-up" air to his furnace. This will prevent a negative pressure situation from happening when exhaust air goes out his flue. The air going out has to be replenished from somewhere and without a source to get it from, it tends to draw air in down the flue as the hot air goes out the very same flue. Needless to say, the flue won't be working like it should and will often draw carbon monoxide back down into the house. His is not connected to his furnace and make-up air is flowing into his furnace room as exhaust goes out. I would think his furnace rooom might get pretty cool in winter.

In your case, that cold air would come into your fish room. A situation I think you would want to avoid.

Just an aside.....

I have never seen an intake setup like yours. Why would they want to draw in cold air from outside to heat when they could be re-heating already warm air? Could be that that is how the contractor decided to get some make-up air into your house.

Needless to say, I haven't seen everything.

 

[capncapo]

Hawk66,

One more thing.

IF your air intake is on some type of damper that opens when the furnace is on and closes when the furnace shuts off and IF there is a reasonably good draw on that line, it could be used to draw humidity from your fish room BUT unless your furnace can pull that type of draw, one or the other ( fresh air intake or fish room intake ) will be lacking. You could try to put a sort of "choke" in your cold air return to guarantee that the intake line is bringing in more air than the rest of the cord air return duct.

To do that, you can cut a slit in your return at some point that comes AFTER your Tee. You can bend a piece of tin in the shape of an "L" and slide the top part of the "L" into the slit. The bottom part would be used as a way of holding the piece in place. Just screw through the bottom of the "L" into the duct and then tape up whatever small slit that remains or just simply tape the thing in place. The size of the top of this piece will determine how much air can get past it. You can experiment with different sized pieces to see which gives you the amount of draw that you want.

 

[hawk66]

I agree it is an odd set-up. I'll be checking into it. Thanks for the help.

 

[skippyreef]

This is my make up air return. As Capncapo said I have an additional line for the cold air return. It does pull in more make up air when the furnace is running in the winter and makes it a little chilly by the furnace.

 

[skippyreef]

here is a length shot of the HVAC line on one side of the basement.

And this is my old 180 LOL (found a pic of it in my album) I am hoping to do much better after this new tank is up!

 

[Whaledriver]

If you put in a air to air heat exhanger you can warm the air in the winter or use the heat for to save money in the winter

 

[outtacash]

Ahem.... a very basic question here. Is everyone cutting holes in their cold air return ducts because there are NOT existing vents in the room already?

More specifically, if my tank 270g total vol. is in a room that already has a cold air vent, I don't need to perform this mod? Should I try to hook into the cold are return closer to the tank?

Would it be better to have a good ceiling fan to make sure that the humid air is making it to the cold air vent? or should I spend the money on a local dehumidifier (an less attractive option given what I have read so far) ?

Thanks to those who respond.

 

[capncapo]

Does your tank room have a cold air supply vent or a cold air return vent?

If it's a return vent then you don't need to do the mod. If it's a supply vent then I would add a return vent to remove humidity from your room.

The hottest, most humid air should rise to the highest level in your room. That is where you should locate the return so you can incorporate the hottest and most humid air into your system.

A fan should not be necessary.

A deumidifier may/may not be necessary. I would wait and see how things are after you perform the mod ( if necessary ). A dehumidifier will add quite a bit of heat to your room which will cause your rate of evaporation to become higher.