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Discussion Starter · #1 ·
I have a remodeled basement that is half underground. It has several air vents right above ground level but I feel as though the air vents let in too much dirt/dust as well as insects. My question is, can I somehow close off these vents and just purchase a dehumidifier?
 

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If these vents are there for make up air for the furnace & water heater, you have to leave them open. You can though use cheap blue air filters to filter the air if have to leave them open.
 

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Discussion Starter · #3 ·
If these vents are there for make up air for the furnace & water heater, you have to leave them open. You can though use cheap blue air filters to filter the air if have to leave them open.
They are not there for the furnace/water heater. They are just vent grills to let in fresh air. Something like this

 

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Again, does your furnace or water heater require fresh air, or are they high efficiency types that take in through a fresh air intake. If they are not the later, those vents have to stay open to allow make up air for those appliances.
 

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those are crawl space vents never seen them for make up air or used in full basement
 

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Discussion Starter · #6 ·
Again, does your furnace or water heater require fresh air, or are they high efficiency types that take in through a fresh air intake. If they are not the later, those vents have to stay open to allow make up air for those appliances.
Hmm.. Not sure about what my furnace/water heater requirements are but my furnace/water heater are located in the garage, which has it's own air vents.
 

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I would not close them off, depending on the size of your boiler it needs X amount of sq inches of fresh air for the flame to properly run.

If you seal off boiler room you will be starving the boiler flame for air.


If you HAVE to close them off, and the boiler is in its own seperate room from the rest of the basement you have to put vents in the walls to let the boiler use whatever from the rest of the basement.

Windows will not suffice for ' fresh air vents' since they arent open year round, and would probably be against code.

( i personally dont like that idea, and would leave the outside air vent )

Your boiler mfg. can tell you the specs of how big of an opening you actually need.
 

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alecmcmahon, the OP already stated his furnace & water heater are located in the garage, so in all reality, he can most likely close up those vents, but also, they were placed in the structure for a reason, not just to make it look pretty. I am sure that previously when the home was built, the furnace & water heater were probably either located in the basement, or were going to be placed in there, but things may have been changed during the build.
 

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Discussion Starter · #16 ·
Here, I'll post pictures so you guys can get a better idea. I'm awful at describing things.

This is the water heater and furnace/coil sitting in the garage.


This is the other side of the garage. Entry into the aforementioned basement. You can also see the vents that let in air.


This is the finished basement. It's basically a room inside of a room. The GC did all the wooden framing and the drywalls are attached to said framing instead of the house frame. He framed around certain pipes and ducts and also built a little service entry to give access to the areas. Note the low ceilings.



Here's the access entry


It lead's into this..


So once you're in this crawl space type of area, you will see these vents that I've been talking about.



Those vents are what I would 'like to' close off, while getting some kind of dehumidifier in there to keep humidity levels in check. Currently my hygrometer shows 62% RH @ 70 degrees, which I think is a little high.
You guys are probably right. They might have been placed there for a reason, which is what I'm trying to figure out.

My options right now are to either close them off and add a dehumidifier or to leave them and try to seal off every leak into the finished basement to create an air tight seal.
 

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Hm, strange little area.

Personally, i'd leave it.

Maybe it has something to do with ventilation similar to what'd you see in an attic like a gable vent.

Removing them would probably cut off all ventilation and make the space even hotter and more humid causing mold growth.
 

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Discussion Starter · #18 ·
Hm, strange little area.

Personally, i'd leave it.

Maybe it has something to do with ventilation similar to what'd you see in an attic like a gable vent.

Removing them would probably cut off all ventilation and make the space even hotter and more humid causing mold growth.
I should also state that the vents were there before the basement was finished. Before the basement was remodeled into a room, it used to just be dirt and concrete.

Closing them off would definitely cut off ventilation. Now I'm not too sure about this, I'll have to check later, but I think there might be an air duct from our central ac that blows into here as well. I know that when the air turns on, I can hear a strong gust of wind blowing.

I was hoping that I could take care of potential mold/mildew problems with just a dehumidifier. You can see from those pictures that dust and dirt from outside really get into that area. Along with all sorts of insects. The basement is remodeled to be a living quarter so it just feels weird to know on the other side of the walls is filled with so much dust/dirt and bugs.
 

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I think somebody mentioned it above, why not get one or two of those cheap fiberglass filters and cut it to size and fit it in nice and snug, should prevent crap from getting in, but still ventilate the area if necessary.

as far as having a cold air supply in there, probably un-necessary and lowering the efficiency of your system, maybe cap it off, and then insulate the room, if not fully done already ?
 

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Discussion Starter · #20 ·
I think somebody mentioned it above, why not get one or two of those cheap fiberglass filters and cut it to size and fit it in nice and snug, should prevent crap from getting in, but still ventilate the area if necessary.

as far as having a cold air supply in there, probably un-necessary and lowering the efficiency of your system, maybe cap it off, and then insulate the room, if not fully done already ?
Oh, I had no idea I could just use a fiberglass filter. That sound's like a great solution. If I do go this route, I would not purchase a dehumidifier. So I need to be certain that putting one of these filters to cover the vent will not have any adverse effects. What do you think?

Personally, I don't know the first thing about insulation. I do know that there is hardly any insulation in the room. The grey plastic sheet insulation that you see in some of those pictures is pretty much the only insulation. I have no clue how I would go about insulating the space because some areas are unreachable. The central a/c doesn't blow into the living space so in the future I did want to add a mini split a/c. You're right however, that cold-air supply is probably unnecessary. It doesn't get too hot down there and if there was proper insulation, as you said, would fix whatever minor temperature problem there is. I think having a mini split would however, be a nice little luxury to have.
 
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