It's oh so quiet
Since introducing the new Greensource series of air to air and air to water heat pumps this year, one of the questions commonly asked by installers enquiring about product performance relates to sound levels emitted by the units in operation.
As air source technology is still relatively new to the UK market, and installers are just starting to attend the training courses Worcester is now running around the country, it’s understandable there may yet be a few misconceptions amongst installers and consumers alike about exactly how quiet Greensource air source heat pumps are in operation.
Mitch Cogger, product manager for new technologies, explains why he and the team are keen to demonstrate how low sounds emitted from the Greensource air source heat pumps actually are, especially when compared to other everyday noises. He explains:
“When we started work on perfecting the new Greensource series of air-to-water and air-to-air heat pumps, one of the prime considerations was to do everything we could to keep the operating noise of the fans featured in both units to an absolute minimum.
“The result of keeping a close eye on performance throughout development was that we were able to keep sound levels to 53dB(A) for the Greensource air-to-water heat pump outdoor unit (6kW, 7kW and 9.5kW ratings) and to 49/50dB(A) for the Greensource air-to-air heat pump outdoor unit, when used for cooling or heating.
“Importantly, the sound levels recorded from the Greensource indoor air-to-air unit registered even lower on the decibel scale. On a low fan speed for cooling or heating, sound levels reach between 27/35dB(A). This increases only slightly to 39/41dB(A) when operating at medium speed and to 43/46dB(A) when the indoor unit is operating on the highest fan speed setting.
“To get a better idea of how the sound levels emitted by Worcester’s Greensource air source heat pumps compared with some of the everyday noises we hear, here’s a quick guide together with a few facts as a useful point of reference:
Everyday noises in perspective
(Decibels (dBA) / Noise)
150 Gunshot / artillery fire
140 Plane take off / fireworks
130 Pneumatic drill
120 Thunder / loud stereo / nightclub / chainsaw / rock concert / emergency siren
110 Football crowd / personal stereo / car horn / shouting in the ear
85 At this level, protection must be worn in the workplace (Caution: Prolonged exposure above 85dB(A) can damage hearing)
80 Ringing phone / hoover / hairdryer / doorbell
70 Washing machine / dishwasher / television
60 Normal conversation / Greensource air to water heat pump outdoor unit 53 dB(A)
50 Rainfall / Greensource air to air heat pump outdoor unit 49/50 dB(A)
40 Refrigerator / library / Greensource indoor air to air unit between 27-4 6dB(A)
30 Soft whisper
20 Broadcasting studio / whispering at 5 feet
10 Normal breathing
0 Threshold of hearing
Did you know?
• All sound levels are measured in decibel units dB(A), which is logarithmic. This means that an increase of 10 on the decibel scale corresponds to the intensity of the sound increasing by a factor of 10. Generally speaking, 0 dB(A) is the softest sound a person can hear and 150 dB(A) is associated with the kind of noise level you’d expect from gunshot or artillery fire.
•The rock band, The Who, were credited with the loudest recorded decibel level for a live concert with 117 dB(A) at an open-air concert at Charlton Athletic football ground in 1973.
•Brushing your teeth with an electric toothbrush is actually noisier than sitting next to Worcester’s indoor air to air unit. An electric toothbrush will produce between 50-60 dB(A), and a normal conversation will register at around 60 dB(A). Makes you think, doesn’t it.
•According to guidelines published by the World Health Organisation, a loud radio will hit levels of between 65-75 dB(A) and a heavy lorry around 7 metres away can expose ears to around 80 dB(A). Both are far higher levels than Worcester’s Greensource air source heat pumps.
Date published: 14th August, 2008
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