Re. "Cities deal with concerns over heat pump noise" (The Tri-City News, March 2).
Fifteen years ago, I worked in an industry where I had to deal with noise complaints from time to time. I can empathize with Timothy Lim of Port Moody, who has a heat pump whose noise is disturbing his neighbour's sleep.
First, the location of a heat pump should be considered carefully prior to installation. Noise decreases with the square of the distance between the source and the ear. The more distance separation, the less noise.
Next, the heat pump unit must be installed carefully to minimize vibration. It should be securely bolted to a heavy, level foundation to reduce vibration of the unit. All panels, grills and doors on the unit must be tightly secured to prevent vibration (and rubber shims added, if necessary).
Third, a sound barrier may be installed between the heat pump and the offended ear. Mr. Lim has installed a tall wood fence. The devil is in the details. The fence must be without gaps and long and tall enough to break the line of sight between the noise source and the ear. A pre-cast, modular concrete fence would offer superior noise-dampening performance.
Another way to add a sound barrier would be to upgrade the bedroom window on the neighbour's house. A non-opening, triple pane window installed carefully with insulation in all spaces around the frame would significantly reduce the noise level inside the neighbour's bedroom. Mr. Lim could, of course, offer to share the cost of the window upgrade.
Finally, the heat pump needs routine maintenance. The accumulation of dirt and debris on the fan's blades will cause imbalance and noise. Worn gaskets will permit vibration and noise.
People expect peace and quiet in their home for restful sleep. It is not appropriate for civic officials to suggest that noise complainers just have to grimace and bear it. Every community must have a carefully thought out noise bylaw that ensures a level of 45 to 55 decibels at the exterior wall for new installations.
D. B. Wilson, Port Moody