The quietest heat pump is the ductless or mini-split heat pump. But, are you asking about a ductless or a full system with duct work? New standards and competition have made most any of the new heat pumps quiet enough for most home owners and neighborhoods.
The Trane XV19 has passed some of the most stringent tests for noise in Seattle, Washington. The Trane company worked with the city to develop a heat pump to work in closely knit neighborhoods where heat pumps had been banned because of noise.
The XV19 outdoor unit looks just like a ductless heat pump but will match up to an indoor unit for a complete duct system.
The problem with some manufacturers, in my opinion, is their planned obsolescence. Try to get some parts when your system ages some. If you can get them plan to spend dearly.
Before I go too far here let me interrupt this thought pattern of finding a quiet heat pump or air conditioner, especially if you’re thinking of buying a new HVAC system, just read my article about questions you should ask before you buy. There’s 30 great questions in this article.
Now back to finding a quiet unit.
Why are heat pumps noisy? Most noise complaints are about outdoor units not a noisy heat pump indoor unit. If your is 10 to 15 years old that is part of the reason. Newer heat pumps are just flat out quieter.
I did some research into noise levels of 14 SEER heat pumps, so if you’re curious about how some of the major brands compare, check it out.
We’ll talk about buying other new heat pumps and also how you can make an old heat pump much quieter.
For your old heat pump, that works okay but just sounds a little noisy here are three things you can do now so you and your neighbors can sleep better and still be friends.
- Compressor Blanket
- Forward Swept Fan Blade
- Outdoor Unit Sound Barriers (Fence like stuff)
This gray compressor blanket is a universal fitting noise suppressor. It’s available on Amazons website and has simple Velcro attachment to itself after wrapping around the compressor. Read on to find out more about these noise suppressing ideas.
This is a discussion about whole house air to air systems with duct work, not the new mini split or ductless heat pumps that actually are so quite you have to look at the fan sometimes to see if it’s on.
If you want to learn a bit about ductless mini splits, I wrote an article covering there application. You can read it here.
I’ve done quite a bit of research and even though each manufacturer claims they have the lowest decibel rating for heat pumps, let me show you there is just no way you are going to set up a scenario so that you can determine which one is quieter than the other.
Consider first what a decibel actually is. Not the gradual scale you may have supposed.
What is a decibel? Zero decibels (0 dB) is the quietest sound audible to a healthy human ear. From there, every increase of 3 dB represents a doubling of sound intensity, or acoustic power.
noisehelp.com
That means a heat pump with decibel rating of 58 has twice the intensity or acoustic power of a heat pump at 55 decibels.
The weakness of these ratings in regards to heat pumps comes into play when you consider that there is no governing body that has a set of rules to measure decibels for all the different brands.
I just watched a video of a supplier for a popular brand name piece of equipment, holding a sound meter near a heat pump to measure it’s decibels. In the demonstration he said that he was holding the meter about three feet away from the running machine.
Conversation in restaurant, office, background music, Air conditioning unit at 100 feet.
Industrialnoisecontrol.com
One test at 3 feet and now one at 100 feet. How far away from the machine do those who test their equipment hold their sound meter?
What are the surrounding conditions for the test? Warehouse? Small testing room? An open parking lot? An installed unit on a house?
It hasn’t been until very recently that those who measure furnace filter efficiency have created a standard method to measure filters called the MERV rating.
Until manufactures of heat pump get together and set up a universal testing criteria then who really knows which one is the quietest.
What Does My Heat Pump Compressor Location Have To Do With Noise?
Improper installation location is the primary reason for heat pump noise complaints.
With housing set backs as small a 5 feet it really complicates the installation of outdoor units. Picking the ideal location to satisfy your noise requirements as the home owner can keep the neighbors up at night.
Even with larger lots and open areas, sound travels in mysterious ways. It can turn a nice neighbor into a grump.
So, if location has more to do with noise reduction then maybe finding the quietest heat pump could be less of a buying factor than you may suppose.
Manufacturers allow as much as 50 feet from the furnace to the outdoor unit and sometimes even more can be allowed and still maintain warranties.
Your installer will know the proper size and length for refrigeration lines to the outdoor unit.
Such a distance offers most home owners a lot of choice in outdoor unit location to focus the noise to the best area. Even the front of a home can be a good location with proper shrubs or bushes to conceal it’s location.
Building fences around units to quite them down offers another set of obstacles. Airflow around the unit should not be impeded. Designing fencing that allows all the air a heat pump needs to stay efficient is critical.
Shrubbery or bushes around the outdoor unit need to be loose in density allowing air to flow and not grow into the equipment.
Forward Swept Fan Blades For Quieter Heat Pump Operation
QHSF stands for Quiet High Speed Fan. Tested by NASA with the objective of achieving a 6% reduction in fan noise. This is probably a test you could trust.
Although NASA’s test was in conjunction with a other special features, many brands of heat pumps and air conditioners have adopted this design to aid in noise reduction.
Every increment of noise reduction, no matter how small can improve your quiet times and that of your neighbors. Much the same way as the auto industry has improved fuel consumption slowly over time.
These fan blades are an easy DYI project but I wouldn’t change out your current blade without checking with tech support for your particular unit. Changing fan blades can change air flow which can relate to refrigerant pressures.
What Is A Heat Pump Compressor Sound Blanket?
Sometimes referred to as a compressor acoustical jacket, these blankets are constructed of a weather proof material and insulation to limit the noise produced by your compressor. The simply wrap around the compressor and are generally held into place with Velcro.
Some people ask if a blanket wrapped around the compressor in the heat of summer will overheat the compressor? The answer is no. If the unit has the correct refrigerant charge it is cooled internally by the refrigerant returning to the compressor.
Some manufacturers include a compressor blanket in their heat pumps. But blankets can be bought separately and installed on any system.
A compressor blanket is an easy DIY project. Turn off the power. Remove the top of your outdoor unit and carefully prop it up out of your way. A second hand would be helpful. Put the blanket on the compressor and your set. Reassemble the heat pump. Have your forward swept fan blade at the same time and make a big difference in your noise problem.
If your heat pump is older you may have a reciprocating compressor. It’s pretty easy to tell the difference. Do a google search for reciprocating vs scroll compressors. You can peek down inside the unit and readily tell. If it is reciprocating, get a sound insulating blanket.
Reciprocating compressors have a piston with a crank and valves. More moving parts means more noise.
Scroll compressors have made heat pumps not only quieter, but more durable and longer lasting.
So, when you’re buying a new system find the contractor and the price you like, it’s not always necessary to have found the quietest system. Pick the quietest location for the outdoor unit and be sure it has a compressor blanket and a forward swept fan blade.
If you’re sticking with the old heat pump, add the appropriate accessories and make it last as long as you can.
