Are Heat Pumps Noisy
Before we can answer the question “Are Heat Pumps Noisy”, it may be best to understand how noise works, or at least noise levels.
Noise is created through vibrations. The vibrations create wave patterns in the air and travel through it till they reach us and we hear these vibrations as noises. These waves have energy levels that dictate how load the noise will be at our end. The good thing is that as sounds travel then begin to lose energy and will eventually peter out till they are inaudible.
Sound is recorded in Decibels or dB for short. The lower the number the quieter the noise, and the higher the number the louder the noise. They measure dB in what is known as the logarithmic scale rather than a linear one.
In a rough rule of thumb every increase of 10 dB is about double the last one. so 10 dB doubles to 20 dB and doubles again to 30 dB. So a sound attenuation that reduces the dB rating by 10, is halving the sound output of the equipment.
Sound and Heat Pumps
Heat pumps are usually rated under dbA @ 1m. This means the noise free to air at 1 meter distance from the heat pump.
However, the sound of concern is often, will it annoy my neighbor, or keep me awake at night. So the sound level several meters away from the heat pump is the noise level to be considered.
Starting at 1 meter away, for every doubling of distance the dB level reduces by about 6 decibels.
Thus a noise at 75 dBA @ 1m will reduce to about 57dB by it is 8 meters away. Or from noisy to about the same as a normal conversation level.
Heat pumps noise levels will vary with the size of the system being used, as well as type of compressors and fans being selected.
For example, a Sanyo compressor is quieter than a Copeland compressor and a centrifugal fan is quieter than a prop type fan. Fan selection is one of the key criteria of heat pump noise.
A small home heat pump will typically have a dB rating of around 50 to 70 dBA, and a larger commercial system up to say 90 dBA.
To put this in perspective a normal domestic refrigerator hums at around 40 dBA and an air-conditioner would run at about 60 dBA. And noises usually do not become annoying till they are above 70 dB, which is about where most noisy washing machines run at. Car noise and heavy traffic sit at around the 80 to 90 dBA level.
Sound Attenuation & Heat Pump Noise.
Toyesi heat pumps have dBA ratings from about 60, for smaller heat pumps, right up to about 87 dBA for our larger commercial heat pumps.
These levels are fairly typical in the heat pump industry. Some brands offer very quiet systems by using inverters to slow fan speeds, and slow compressor speeds. This however can reduce the output of the heat pumps performance. Not wanting to risk the capacity our our heat pumps, Toyesi designed our sound attenuation kit.
The sound attenuation kit covers several key things to reduce sound level.
- Vibration Pads – Reducing vibration to the surrounding floor.
- Sound Attenuation foam – Using sound dampening foam inside the heat pump reduces vibration noises from the compressor or fan motor. Some companies offer sound reducing jackets for compressors.
- Fan Upgrade – Prop fans are very noisy as they chop at the air. We remove the prop fan and replace it with a highly efficient centrifugal fan. These fans hum rather than chop at the air, again reducing the sound levels without compromising performance.
- Sound Attenuation Box or Kit – A metal box with sound foam through out, designed to break up the air flow, and disperse the air significantly.
We find the sound attenuation kit can reduce the sound output of our heat pumps from 10 to 20 dBA depending on the size of the equipment. In general, the larger they system the better the sound reduction.
Other Sound Reducing Ideas
There are a few other ways you can reduce heat pump noise levels.
- Distance the equipment away from sensitive areas. Remember the dB level reduces the further it away from a sensitive area.
- Point fans away from any sensitive area. Since air carries sound and the noisiest part of a heat pump is the fan. By pointing the fan away takes the noise away form the sensitive area.
- Sound screens or walls can be used to break the air flow and thus reduce sound levels. The patterns, although often pretty, on the walls around roadways is just that, a sound barrier to break apart traffic noise.
- Bushes or plants – just like a sound wall, plants break noise in their leaves and disperse the noise around.
- DO NOT place the heat pump in a place close to walls that might echo the sound. These areas will only increase the noise levels.
- Install the heat pump in a plant room. First being indoors it supplies a natural sound barrier walls around, but also properly designed and fitted implant heat pumps (See Indoor options) will act as a mini sound attenuation kit reducing noises levels significantly.
Understanding peak use COPs is your best ammunition for selecting the correct heat pump for your swimming pool project.
Inverter technology, offer even higher COPs. however these again are based on lowest heat loads and lowest demands, making it easy to achieve these values. However, once you realise the COPs in mid winter under full load, they do not differ significantly form standard non-inverter heat pumps.
The other significant factor that makes Toyesi heat pumps have higher standard COPs is that we size a unit based on a few factors.
- Pool location and environmental conditions.
- Desired heat load at peak use period.
- We design the system around the compressor capacity, rather than a generalised system.
- We select components to support the maximum output based on the compressors capabilities.
- Rather than a extra large coil, we use a 5-deep coil for maximum heat absorption from the air.
- We have our trade-feature water balance COP kit. allowing for fine water trimming to maximise COP all year round.
- And other in house trade secrets.
- Side or end mounted fans rather than top fan. This prevents the cooler discharge air falling back down and being recirculated through the heat pump super chilling the system in the process. Known as the mushrooming effect, that decreases significantly a heat pumps performance.
So to answer the question “Are Heat Pumps Noisy”, comes down to size, installation location, sound barriers used and whether or not you use sound attenuation.
However, you will find at about 10 meters distance plus the noise levels are often less than that of air conditioners and with care and forethought will not annoy your neighbors or yourself. With that said many people opt to use the heat pumps during the day, and only at night when needed.
One key thing you can do for yourself is the use of a pool blanket. They help keep the pool clean, reduces heat loss, reduces running cost of the heat pump by at least 40%, and all those facts means less operating time and thus less noise produced.
Want to Know More?
Sample collection of Toyesi & Trident Heat Pumps and Chillers..
If you want to now how Toyesi can help you and your water or pool heating project increase energy efficiency, reduce running costs or minimise your waste energy then give us a call.