Proper way to vent basement woodshop
Hi, I am slowly putting together my basement wood shop and wanted to know how I can safely vent the basement without backdrafting my gas fired boiler. I have a humidity problem in the basement and there is some mold growth on the peices of lumber I have down there as well some rusting beginning to occur on some of my tools. As a start, I plan on installing better windows that will allow me to have screens in them. I don’t want to do the de-humidifier route because I hear they just cause my electric meter to spin fast. I was told that an air exchanger might work (the kind they use for radon abatement) , they use less electricity but cost alot. I’m concerned about sucking the exhaust gases from the gas fired boiler back into the basement if I use a vent fan that’s too strong. I live outside of Philadelphia Pennsylvania. Thanks.
Replies
An air exchanger would only help during the winter months. During the summer when the humidiy is highest, it would actually make things WORSE.
During the summer the outside air is warmer than the air in your basement. So when you bring it in, the relative humidity increases.
Your best bet would likely be to deal with the moisture issues outside. Get the groundwater drained away from your basement.
Running an AC vent into the shop might help keep the moisture down, if you have central air.
Then - Like it or not - A dehumidifier is probably your best bet.
I say: Know your enemy and know yourself; in a hundred battles, you will never be defeated. [Sun Tzu]
Based on where you live, the best approach is to seal it up and dehumidify. As a former Baltimoron, I can tell you that humidity will ruin things very quickly. A decent dehumidifier will run at 300 watts. If you use it 12 hrs a day, thats 3.6KWH or about 40 cents, or about $12 a month. At least in the winter that energy will be useful heat. Figure out what your losses will be if you don't dehumidify. I bought a sears dehumidifier 12 years ago and ran it 24/7 in the summer in Balmer. It still runs a couple of 3hr stints a day here to keep things dry and circulated. Air exchange will just bring humid air into your basement in the summer.
I installed one of these at home this summer, and it is like night and day. The water came pouring out when we first turned it on. It is an order of magnitude more efficient than anything you'll find in the store. It's drawback is the price tag, but you'll get your money back in energy savings.
http://www.thermastor.com/DesktopDefault.aspx?tabid=248
Price?Our quarrel with the world is an echo of the endless quarrel within us. - Eric Hoffer
I just compared operating what I can generally find here for $30-50 used (50 pint). Wow! If you'd post your cost I could figure a payback period.PAHS Designer/Builder- Bury it!
Yeah, that was my reaction when I first saw the price. I think I paid something like $1200. I figured I'd save $100-150 per year (at *current* energy prices) over a conventional dehumidifier, so payback in 10 years (or less with the current trajectory in energy prices).
More to the point, my wife was skeptical until we turned it on and she saw the difference it made in the basement environment, even over an existing dehumidifier.
Yeowch! I'm only running $100-150/yr total dehumidification cost now. That difference your wife saw, is why we use a second dehumidifier, occasionally run. We constantly monitor humidity and turn things on accordingly.
Gotta think about this. Thanks for the information, saved the site. I hope the fan is better than the crappy ones Sears uses. Oddly enough I just now unloaded a 30 pint unit onto a neighbor- but it had a replaced fan motor, a good one. 30 pint I quit messing with some time ago. All Sears have the same current draw: 30,40,50 pints are all the same. Go figger. Now I'm down to only 2 spares (plus the 2 in the house). Total investment of $300. <G> I hear you about projected elec costs.
Don't know your possible application, but we installed a heat pump water heater a couple of years ago. Helped immensely with dehumidification, and cooled off the house a little in the process. Not to mention the primary product, cheap hot water.PAHS Designer/Builder- Bury it!
A woodstove is your option to look at..dry heat fast, and not always a long burn..I lived in the same area, had two subterrainian shops, all wood heat..even in july, I could do a small sawdust/scrap fire.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
One other idea for a ventilator in your basement, if you do need a fresh air source down there is an ERV unit from Renewaire (the product is called "Breeze") that uses an enthalpic membrane to transfer only air from inside to outside while keeping not only the heat on the warm side, but also the humidity. Most HRV units only keep the heat on one side, but let the humidity pass thru, meaning that often an HRV unit has to be shut off in the summer months. The enthalpic membrane keeps the humidity on the warm side, good for both summer and winter.
I just installed the Breeze in my workshop this summer (which is a VERY well insulated and sealed space which needed fresh air somehow, but the outside air was too humid to just open a window). The air is always fresh in there now (great when using solvents or painting) and it keeps my inside air dry in the summer and should keep it not too dry in the winter (I'll find out soon).
In a basement you'll still want a dehumidifier though, because of the cool cement surfaces that will try to condense out much moisture regardless of what else you do. I find that I still need one in my workshop, but don't use it quite as much as before, with the ERV running.
Just a thought,
Norm
Haven't noticed the same problem in Colorado. Maybe some ducting from your place to mine with a reversible fan? Could use some of that humidity in our forests. Tyr
Im with sphere.I have the same situation in my shop in town.Done all i could do to mitigate water from outside( believe its just a nearby spring).Ran gas furnace last year which was the first heat Ive ever actually paid for in my life..and Im 50.So I religned and old flue for a woodstove and imdrying the place out with good old free wood heat.As far a summer its anice cool place to work but open the door or run a fan and u can see the color of the cement floor start changing once the hot ouside air hits the cool cement.Ill try some wood heat in summer to keep ambiant humidity down but will see if have to go dehumidifier route.
Brother had an addition done on house. Seems there was something like a layer of shale just below where contractor dug. Ground water plus a small spring sent water along the shale to his new basement. He put in a sump pump just outside the basement in concrete culvert stacked on end. It intercepted the water, pumped it out with a float activated switch. Top of culvert was covered except for a hole for the garden hose. There was just enough pressure to run a little sprinkler so he ran the hose on the lawn downstream from the spring. Basement dried up, lawn was green--everybody happy. Tyr