Heat pumps are often touted as the heating and cooling system of the future. Not only are they better for the environment—and often cheaper than their furnace and boiler counterparts—their highly-efficient designs have been embraced by governments. This year, the Ontario government even announced a new rebate program that could save cottagers up to $12,000 in ground-source heat pump installation.
But with all the highs of heat pumps, one issue has loudly emerged (no pun intended): noise concerns.
Just last month, the Vancouver Island District of Oak Bay amended its municipal noise bylaw to limit how loud heat pumps can be. The systems are now restricted to 50 decibels between 7 a.m. and 10 p.m., dropping to 45 decibels at night.
The move follows complaints from locals concerned about sounds emitting from heat pumps in the community. Oak Bay isn’t the first to set a noise limit on the heating system—Ottawa, Victoria, and more have also amended their bylaws.
So, just how noisy are heat pumps? And is there a way to quiet them down? We sat down with Jeff Hunter, the co-founder of Evolved Thermal Energy and president of the Ontario Geothermal Association to find out.
How loud are heat pumps?
Each type of system has a different sound level rating. Geothermal heating is the quietest option, though outdoor air-source heat pumps tend to be more popular.
Most modern outdoor heat pumps emit around 60 decibels of sound. For comparison, 40 decibels is compared to a quiet library while 60 is similar to a refrigerator hum. Indoor units can be particularly quiet, as low as 18 decibels.
Both systems use compressors and fans to circulate heat, creating a low humming sound. When these systems are under more pressure to move energy on hotter or cooler days, the motor has to ramp up to full load condition. “That’s when they’re the noisiest,” says Hunter, though he expects most systems to hit this peak less than five per cent of the year.
Overall, the sound emitted from a heat pump isn’t too different from a traditional air conditioner.
Are there ways to reduce noise output from a heat pump?
Some noise from a heat pump is inevitable, but there are strategies to keep yours quieter. Most experts recommend placing outdoor units away from windows and nearby buildings—B.C. requires a three-metre distance—to reduce output.
“Be smart about the positioning of the heat pump on your property,” says Hunter.
It’s common to instinctively install a new heat pump where your old air conditioning unit used to sit, but it might be too loud. “We’re used to A/C running in the summer, but hearing a heat pump running on a cold, winter night can be jarring,” says Hunter.
The type of unit also matters. A side-discharge air-source pump that faces the direction of an adjacent property could be bothersome to your neighbours, while a top-discharge unit may be louder for you as the sound moves upwards in your home. Sit down with your HVAC technician to figure out the best location for your property.
As the technology continues to advance, many “smart” systems are fitted with nighttime or low sound modes, insulated compressors, and decibel limits. Placing an outdoor heat pump on a concrete pad or vibration-absorbing mat can also help reduce noise.
If your heat pump is making any unusually loud or rattling noises, it may be time for a tune-up.
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