QUESTION: Our laundry/furnace room is directly below our bedroom. I have recently installed Roxul Comfort Batt Safe & Sound batting in between the ceiling joists under our bedroom to reduce the noise from the electric furnace. I would like advice on how to further reduce the noise. There is no fixed or suspended ceiling in this area. The laundry/furnace room is separated by two-by-fours from the rest of the finished rec room. Would it help if I moved the batts down to the level of the bottom of the joists, creating an airspace above them, or install a second layer of batting? Thank you for any help you can give me.
Sincerely, Jack Middleton
ANSWER: I may be able to offer some advice about further improvements to your soundproofing attempts, but I think your focus may be on the wrong subject. Electric furnaces are normally very quiet when operating, so modifications to it or the other components attached may yield better results.
Electric furnaces are almost silent in their operation, with the exception of the air-handling components. This includes the electric motor and blower and the ducts through which the air moves to heat the home. If your furnace is noisy when operating, I would suspect that either the blower motor is in need of maintenance or repair or the ducts are at fault. If you hear a whining noise when the furnace kicks in, it is likely due to the blower motor. As this common electric motor operates, the lubricant may begin to deplete. Many motors can be quieted simply by lubricating the motor, as per manufacturer's instructions. If the whining is very intense, and the motor housing becomes quite hot to the touch when operating, the bearings may be worn out and replacement of the motor will fix the issue.
Alternatively, the blower or its attachments to the furnace housing or motor may be at fault for the excessive noise. Many older furnaces have a flexible belt that connects the blower to the motor. These belts become worn over time, can stretch and make a racket due to the looseness or deterioration. Again, simple replacement of the belt may make the unit quieter. Lastly, blowers often sit on adjustable mounts or other connections to the furnace housing and may become loose, corroded or damaged. When this happens, the blower can vibrate or rattle, creating loud noises that reverberate through the entire duct system. Calling a licensed HVAC contractor to adjust or repair the rattling blower should quiet this issue and make life more bearable.
The other noise complaint related to forced-air heating systems I often hear from homeowners is the sound of the air movement itself. This can be due to initial design of the ducting, with too many sharp turns or poorly secured ducting. It is also a common occurrence when fan motors or blowers are replaced, and is due to the increased performance and higher velocity of the air moving through the ducts. If any of the older ducts are loose, partially disconnected or have dampers closed, then addressing these issues may calm the problem. If you have recently upgraded the heating system or blower components, there may be little you can do to stop the annoyance.
It is not a bad idea to insulate between the joists below the main floor to prevent sound transmission, and covering the ceiling will further improve the soundproofing. Installation of a drop ceiling, with tiles designed for acoustic improvements, should help the mineral-fibre batts in decreasing sound transmission between rooms. If you don't have enough height for a suspended ceiling, installation of thin, sound-absorbing materials such as burlap or cork may help. Again, it surprises me that only the furnace noise is mentioned when the washer and dryer in the same room can make equal or greater noise than the heating system. Perhaps they are not often used at night when quiet is most desirable in your bedroom above. This may be another way to test -- turn on the washer and dryer just before going to bed to see if further soundproofing is warranted. If little noise from these two appliances is heard in the bedroom, addressing the furnace itself is the solution.
There are many components in our homes that appear to cause issues when the true culprit is something entirely different than many homeowners assume. Home inspectors are trained to look at the entire house as a system comprised of many smaller systems. This approach, while straightforward, can help analyze and pinpoint issues that may arise. Very few components in our homes work in isolation, and almost all have effects on other systems within our living spaces. Though it may seem that the annoying transmission of sound from the furnace room to your bedroom is due to lack of proper acoustic insulation, it may simply be that the heating system itself is in need of repair or upgrades.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and president of the Canadian Association of Home & Property Inspectors-Manitoba (www.cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358, or check out his website at www.trainedeye.ca
trainedeye@iname.com
