For years we used portable CINNI fans as our main source of ventilation. We chose these old-fashioned metal fans because they are incredibly durable and can be moved around as need be to break up hot and cold air pockets. We’ve been very happy with these simple, low-tech fans. In 1996 an old fashioned style metal fan was rare, most fans were plastic and broke within a season, luckily now in 2008 durable metal fans are much more available and we still find them to be the best solution for spot cooling or moving air around.
In addition to the CINNI fans, we also have an exhaust fan above our stove. However, we’ve found we must be careful when running this fan. If an exhaust fan is running when all the windows and doors are closed, a vacuum could be created, sucking in toxic fumes from the vent which vents toxic combustion gasses from our propane-powered hot water heater and clothes dryer. We avert this problem by simply cracking open a window any time the exhaust fan is running.
Although our bathrooms lack a ventilation system, moisture monitors indicate that our bathrooms are quite dry, with moisture levels rising up to the normal range only when someone is showering or bathing. In addition, we have never had any mold or mildew problems. The lime plaster kills mildew and mold on contact, and we believe that lime plastered bale walls breathe, sucking up moisture in one part of the house and releasing it to drier parts of the house, as well as outside. In fact, we have never seen or smelled mold or mildew anywhere in the house. Even the indoor air quality specialist who tested our bathrooms found no evidence of mold or mildew. This is most amazing, since one of our shower walls is a plastered bale wall protected only by a shower curtain.
We have had our basement tested for radon, and fortunately none is present. Even if it were, it wouldn’t have been such a problem, since dry laid stone is not airtight and breathes quite nicely.
In our new building we have installed one vent fan in the primary bathroom and will be installing a vent fan above the stove. Our new building will be tighter than our old building and the building scientist we consulted felt that a low energy using bathroom vent fan was the best solution. He felt that a Heat Recovery Ventilation (HRV) system was not necessary in a building of the size and construction methods we are using. While HRV systems are now the norm, we strongly suggest that you spend $100 or so on a consultation with a building scientist, our consultation resulted in our spending about $120 for a single vent fan as opposed to a few thousand dollars for an HRV system.
Because we have a fully insulated basement in the new building we will be testing for Radon.