Shopping around for a new central residential heating system to replace your aging furnace requires you to consider dozens of different factors and features among different models. If you're considering a heat pump for its energy efficiency and option for ductless installation, you may be worried that switching to a system with an outdoor unit will create extra noise that bothers you or the neighbors. Learning the facts about how loud a heat pump really is will help you make the right choice for your heating needs.
Inside the Home
The indoor unit that blows the warm air around each room is a little louder than the noise you'll hear from furnace registers, but the noise level is about the same as you get from a furnace once you factor in the quiet rumble of the blower. Heat pumps produce around 17 to 20 decibels of noise from their indoor units, which is quiet enough most residents will rarely notice it at all above the ambient noise factor inside the average house. Even if you're sitting right under the indoor unit, it won't interrupt your enjoyment of a television show or music.
Outside the Home
It's the outdoor unit that most people are concerned about being too noisy since it's likely to be located relatively close to your neighbor's home as well. The exact decibel level produced by a heat pump is rated as a maximum number that the system should stay below. For example, most heat pumps sold in the US are rated to offer an outdoor noise level of 50 to 60 decibels or less. A refrigerator is around 50 decibels when actively cooling, so no one in your neighborhood should be bothered by a heat pump running normally, even when they have the windows open.
A heat pump will get a little louder when it switches into defrost mode to remove any ice accumulating on the condensing coils. This should take only a few hours at the most, so a heat pump that suddenly becomes louder and doesn't go back to its normal quiet operation needs professional attention. Louder noises are definitely a sign that there's something going wrong inside the unit.
Each model varies in noise, so check the manufacturer's decibel ratings if noise is a major concern to you. The mid to upper 40s are usually the lowest sound level you'll find from a heat pump, but most people are hard-pressed to really hear a 10 or 15 decibel difference, especially in an open environment like the outdoors.