With the advice of staff at Amre Supply (to help me choose the correct product), I purchased and installed a "Panasonic WhisperCeiling DC Exhaust Fan, 50/80/110 CFM" in the rumpus room of my basement. The fan cost about $220 plus sundry supplies and my time. My goal was to ensure that I have at least 3 whole-house air exchanges every 24 hours to reduce indoor air pollution, which includes radon. The fan runs continuously, however, it has 3 dials that permit a variety of settings and it is switched at the wall to provide a temporary boost in fan speed. I am delighted by this product. Surprisingly, the air is exchanged without the house feeling drafty (it definitely smells better in spite of the dog), the temperature of the house stays more even (I have a variable speed furnace that I run continuously), humidity has dropped to below 35% and when the temperature dropped to minus 25 degrees celsius for a few days, by increasing the fan speed marginally, I kept the ice off the windows (first time in 15 years), and the radon levels have dropped to just above 200 becquerels (200 bq is the limit suggested by Health Canada). Fortunately, the fan is very quiet and we don't notice it operating while we watch tv or read in the basement. This has been a very inexpensive solution to solve my radon problem (which was originally tested at just under 900 Bq) & my humidity problem simultaneously.