Ducting, Air Circulation and Ventilation Systems - basement ventilation system - DIY style?

A friend of mine had a rather basic basement ventilation system installed. Having been in his basement a number of times and experiencing the noticeable dampness/musty smell, with 2 dehumidifiers running no less, I was really interested in seeing what this new ventilation system was all about. I get over to his house, and have to say, first and foremost, his basement was 100% better just walking down there. But when I got to see the unit (for which he paid $1200 installed), I was a bit mystified. Basically, its a fan unit near the floor of his basement, a duct running up the wall, and that duct heading out through the top of the basement wall, with a hooded exhaust. $1200??? I guess the idea is, this thing pushes out the dampest air (bottom of basement), and because it is pulling air out, it causes air to be pulled in from upstairs. He said he found 2 advantages, one being a significantly less moist basement, but also better heating upstairs, as his heat vents are at the ceiling, and better heating in the basement. There are supposedly similar benefits in summer in conjuntion with AC, the key being the removal of the moist basement air. This all sounds attractive to me - but it also begs the question: Why can't I just make one of these myself using a powered vent fan ($75), some ducting up the basement wall, and vent out through a basement window??? Is there some component of this that I'm missing??? Thanks for any thoughts.

First Id have to ask . Did he have heat outlets down there? You also have to have some return air to the furnace and for the AC. Also id say his fuel cost will go up. That fan bloweing out down there has to pull cold air into the home from some where .

Are you sure it wasn't an HRV or ERV? They use a heat exchanger to warm the incoming air with the warmt exhaust.

A straight exhaust fan like that could cause negative pressure in the house and if he has a gas water heater, conventional gas furnace etc., that equipment might not vent properly causing risk of carbon monoxide poisoning.

Thanks for the response. Those are similar questions that I had, and honestly don't have the answer to. He just had it installed because the mild winter was making his basement pretty bad. I do know that he has the ability to heat the basement (there is a vent there), don't know about a return. His furnace is a forced air type in a separate area of the otherwise finished basement, similar setup to mine.

It is those questions that make me wonder, and $1200 seems pretty steep. But, I will say one thing that is an absolute fact, his basement is way more acceptable now, it's a major change and the musty smell wasn't noticeable last time I was over there. Honestly, if it ends up costing more to heat in exchange for a livable basement, I would say that it would be worth it to him, as the basement is a space their family needs.

Since I have gone through similar issues, though nowhere near as bad, the change he experienced seems worth pursuing. One major difference for me is I put down 'Dri-Core' and he just has carpeting on painted concrete. Nonetheless, I experience moisture issues especially in summer that my dehumidifiers can't seem to conquer as well as I'd like. I guess my thought is that if I can fashion something similar for a couple hundred bucks with the chance it could help during the worse months, maybe it's worth a try? If it creates a negative effect elsewhere, remove it, but at least I'm not out $1200.

I wish I knew enough about airflow, pressurization, etc. to determine the true dynamics of adding something like this. The system is called 'Ez-Breathe', and the documentation refers to the website ezbreathe.com. I have to do more reading on it myself. Experience tells me, nothing is ever what it seems. But his basement also tells me, at least this thing does seem to be solving a problem, albeit at what expense?

It would be nice if that web site actually showed a CFM number. I'm surprised that it didn't. If you want to do something like this, why not do it using an ERV or HRV depending on where you live. It's a balanced flow device. Maybe $600 or so if you install it, but I would think it would be much more energy efficient and also safer for your combustion equipment.

If you exhaust your house, then moist cool air gets sucked in through the walls and cracks. As it comes in it has to shed moisture. Do you have fiberglass insulation in your walls? If so, it works far better when it is dry than moist.

I'm going to snoop around a bit more on the ez breath system.

WHO -

I hear you on the venting issue, excellent point. I suspect the answers are out there on the web, now that I know what the device is. I hope the 'professional installers' took all of that into consideration when proposing/installing the system...? I will ask my neighbor tonight and see what he says. You know, my wife always gets on me because I can't make a decision without consulting web forums - but frankly it has kept me from doing a lot of stupid things. I want to keep my basement living area dry - But Macgyver, I am not.

I want to keep my basement living area dry - But Macgyver, I am not.
I dont see why you cant with just the heat and cool from your furnace and AC down there. All basements here are finished out all the time and we have no trouble at all. we take it as part of the home.

I'm guessing 110cfm... I did send them an email asking them the flow and energy consumption. The closest thing on the web site is $2/month... At $0.10/kWh I'd equate that to 25 watts. I lookded up some exhaust fans in that size and they were 110cfm. I don't think this will endanger anyone from backdrafting, but turn on the range hood, a few bath fans... it all adds up.

I was thinking $1200 i a really good price for an installed HRV, but for a small exhaust fan... Ouch! Oh well... the owner's happy. It only cost him an extra grand for the marketing jargon.

Regarding just heating/cooling - out here, it just doesn't quite do enough, unfortunately. The community borders 2 flood plains, and most of the homes are 1960's & 70's, so less technology in the basement of course than newer homes. I've got new gutters, and reworked the grading around the house, etc., but moisture still makes it in there. The finished area in my basement was done 10 years before I bought it, and who knows if it was really done right. It's completely drywalled, walls and ceiling. Everything still looks good, no discoloration evident - but, I really have no idea what's behind those walls, and maybe I really don't want to know. There isn't much smell even when moisture is bad in summer, to suggest there is mold growing behind there, but every year I tell myself I'm going to do something to get that moisture out.

Last year, I did get a quote for an ERV, $2,700 installed. (Not a straight shot install, a little more than I think I'm comfortable with on my own). Decided to wait. My furnace is 20 years old, and I will likely be adding central air when I replace it, so I decided its best to deal with it all at one time.

It sounds like if I were to try making one of these units, I really need to understand how the negative pressure will effect the rest of the house during both heating & air conditioning, and especially how my gas furnace/water heater will react. Oh heck, what am I talking about, I really just want to build this sucker to tick off my neighbor!!!!!! ;-)

THEN GO FOR IT Macgyver, ;)

I agree that you would do well to just install an exhaust fan.

The type I linked to could be neatly mounted at the ceiling with a duct down to the floor and out of the house through a dryer vent with a back draft damper.
This model is available in 100, 140 and 200 cfm.
I would go for the 200 and you could always damper it off.
If you damper the inlet side of a squirrel cage fan it will reduce the air output and lower the load on the motor.

http://www.broan.com/display/router.asp?ProductID=548

Keep us posted if you decide to do this.

Take a look at Dehumidifiers and Humidifiers section old post I just moved it up!! It says Humidex

I too am interested in this. We have B-dry at our home, this is their third and final day. We opted not to have their "patented evironment" deal done, we did pay $500 to stub out our "system" so that in the future we could easily add it.

However they want $3500, extra for that part of the system, which is basically pictured here minus the rest of the 4" pipe to carry exhaust outside, a hole for it to exit, the fan of course, their fancy fan cover, more pipe, and a pipe cap.

Obviously too much $.

http://img.photobucket.com/albums/v228/harleysilo/Basement/bdry3.jpg

http://img.photobucket.com/albums/v228/harleysilo/Basement/bdry2.jpg

http://img.photobucket.com/albums/v228/harleysilo/Basement/bdry1.jpg

So I too, need to locate the proper fan, been searching everywhere but can't get the specifics of what they would install.

No check valve off of that pump!