"Residential air conditioning noise issues are a common complaint or query – with people often demanding to know who is responsible, what are the penalties, and exactly how much noise, at what time, is acceptable."
INDOOR NOISE
Indoor units contain a fan for moving room air over the heat exchange coil and distributing it throughout the room being served. Fans can generate noise, as can turbulent air flows. Modern air conditioners are generally designed for quiet operation, but indoor noise can be an issue if an air conditioning unit is over sized for the room or zone, or is installed in an inappropriate location.
Ducted systems also have particular noise considerations. Fan noise can be transmitted down the duct, noise can be generated at dampers and air control devices. Also, particularly when systems are not operating, there is the potential for noise generated within one zone or room to be transmitted through the duct to another room. This may be an issue when family or entertainment rooms and bedrooms are served by a common ducted system. Proper duct design, unit selection and the addition of noise attenuates to duct work systems can all help solve indoor noise issue.
OUTDOOR NOISE
Air conditioner noise complaints made to local councils, the police and other government authorities have greatly increased over the past few years. This may be because of increased high density living, and less space between homes, as well as a general increase in the installation of air conditioning in the residential areas. Additionally, poor or inappropriate installation practices, and a poor understanding of environmental noise issues, can also contribute.
Homeowners often aren’t aware that their noisy air conditioner is impacting neighbours, or that by exceeding noise levels they may be breaking the law and could be penalised. However, by raising people’s awareness of noise nuisances and the potential penalties, these nuisances may be reduced.
Limited advice from retailers and installers, and a lack of forethought and planning by owners, retailers and installers on the location and use of air conditioners also contributes to noise issues. Manufacturers, installers and retailers should provide responsible advice and service at the beginning and throughout the air conditioning selection and installation process to prevent noise nuisance.
Any air conditioning manufacturer, supplier or installer claiming compliance with these guidelines should know the sound power level of the unit, and be able to determine whether a unit/location combination is compliant with local noise regulations.
ENVIRONMENTAL NOISE
Noise by definition is sound that is unwanted or unpleasant in some way.
When environmental noise reaches elevated levels in our living spaces, it can have significant impacts on our health and well-being by disturbing sleep and interfering with relaxation and communication. Noise can also affect our performance, learning and stress levels.
The level of annoyance experienced from the noise depends on the level of the noise, type of noise, how often it occurs, how long it goes for, time of day or night and the individual’s own tolerance.
Noise annoyance can result in changes in behavior, such as closing windows, not using balconies and turning up the television volume. In some cases, annoyance can be extreme and can lead to aggression.
MEASURING NOISE
Due to the range of noise that can be heard by the human ear, a scale called the “decibel scale” is used to represent how loud a particular noise is. A decibel rating describes the relative loudness of the sound.
The sensitivity of the human ear to sound depends on the frequency or pitch of the sound, and some people hear some frequencies better than others. If a person hears two sounds of the same sound pressure but different frequencies, one sound may appear louder than the other. Noise measurement readings can be adjusted to correspond to this peculiarity of human hearing, using the measurement dB(A). The dB(A) unit provides a scale for noise level as experienced or perceived by the human ear, see Table 1 for examples of the dB(A) rating of common sounds.
Most modern air conditioners are designed to operate much more quietly than in the past. However, there is still a significant variation in noise levels across a product size range, and between different manufacturers. Manufacturers test the performance of their products and generally include the operating noise levels in their product literature along with the other performance data.
In some countries, manufacturers must display the noise performance data of their equipment on the units.
Noise labelling of residential air conditioners is a legal requirement in some countries and the introduction of a national noise labelling scheme is currently being considered by some countries
Where noise labelling is mandatory, residential air conditioners should have a clearly displayed label which shows the sound power level (Lw) of the outdoor unit.
The sound power level will give you an indication on how noisy the air conditioner will be outside the house. The higher the number, the louder the air conditioning unit will be.
Noise labelling for residential air conditioners provides consumers with more information in order to make informed purchasing decisions. Most of the techniques for estimating noise levels and for determining compliance with local noise regulations will require that the sound power level of the unit is known.