Q. My neighbor has a noisy through-the-wall air conditioner that runs day and night. So that I could get a better night's sleep, I thought I would offer to build him a soundproof box he could place around the AC unit, before I resort to more drastic measures. Is it possible to build a simple structure that will reduce noise, provide the necessary ventilation, and be weather-resistant? The unit is located below a glass-block wall, on the first floor above a concrete walkway with ample space around it.
A. Fernando Pages Ruiz, a building contractor in Lincoln, Neb., and the author of Building an Affordable House, responds: Unfortunately, you cannot build a soundproof enclosure of any kind that would also provide adequate ventilation for the AC unit. Noise travels through air, so by definition a soundproof enclosure would have to be airtight.
The solution to your neighbor's AC noise output lies at your own bedroom window. First, check that your window seals tightly. You'd be amazed how much sound you can block with good weather stripping. Remove the casing around your window and seal the area around the jambs with caulking or expanding foam sealant. If that doesn't help, consider installing heavy, solid shutters that can be sealed tightly. You could also replace your existing window with a vinyl window frame (vinyl provides better sound attenuation than wood) and laminated glass. For a surefire solution, Soundproof Windows (soundproofwindows.com) makes add-on window units (they're used in conjunction with your existing windows) with sound-attenuating frames and glass that can reduce sound infiltration by up to 90 percent.
Otherwise, if your neighbor's unit is showing signs of age, you could ask him to replace his air conditioner with one that has a lower sone rating (sones are used by appliance manufacturers to indicate the relative noise level of their products; a lower number signifies a quieter machine).
