You have to love words that don’t go together, words like “sound”, “green” and “free”. Placed in a sentence as in this title, they don’t appear to make sense. The confusion is that you first have to know what the sound of green is to understand why it is free.
If you are thinking “green” doesn’t make a noise, then you have almost solved the puzzle. You see, green constructed homes are extremely quiet, and this wonderful
“sound of silence” is a free result of the green construction with no added cost or design effort. It just happens. In our new generation of Green Verified homes, what results is a sanctuary from outside noise. As we build houses tighter and tighter for energy conservation, we begin to lose the sounds of trucks on the highway, lawn mowers of the neighbours, and those car stereos thumping down the street.
But even as those annoying exterior noises are blocked from entering the house, other things on the inside of the house that make noises can become more aggravating. Things like exhaust fans in bathrooms. The cheap ones are always too loud and can be pathetic excuses for exhaust fans. In highly efficient green homes, they can sound like a 747 taking off. It is here we may find a bit of hidden cost for our free sound of green…a better fan.
Fans are needed in high moisture areas like bathrooms and they are about the only way unwanted moisture can find its way out of these tight houses. And in a quieter house, inside noises may seem louder, so the tendency is to turn that fan off as soon as possible if it’s noisy, thus defeating the purpose. Well, the techno boys knew we needed quieter fans so they made a better selection. They are not all that expensive; $75 to $150 will buy some of the best. A bargain when considering what they do. But how do you know which one to buy since you can’t take one home for a test drive? Effective and quiet, but how can you be sure?
The techno boys have that figured out also. All they had to do was “rate” them and put the sound rating on the box. (They could have placed a “decibel rating” on the box, but a decibel rating of 45 is twice as loud as a reading of 43. It’s a logarithm thing for mathematical geeks.) So instead, the solution was a rating system called “sones” that is logical to all buyers. A fan with a rating of 2 sones is twice as loud as a sone of 1. The loud, cheap fans are about 4.5 sones. So as buyers, we no longer have to mess up trying to save a few bucks by buying an annoying, ineffective fan.
For our new, super-quiet green homes, exhaust fans should have a sone rating under 1, and most ENERGY STAR fans are under .5 sones or less. You can barely tell they are running. Add a smart sensor switch, or timer switch, and you can remove that unwanted bad air and still enjoy the sound of your “free green silence”.
Jim D. Baker, B & G Drafting—HERS Rater, and NAHB Verifier, LEED AP for Homes