Many clients raise concerns about noise from a neighbour’s outdoor air-conditioning unit, heat pump, or swimming pool pump. A common question is: How loud is too loud? The answer depends on where you live.
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Noise From Outdoor Air Conditioners and Heat Pumps
This article focuses specifically on noise from stationary sources, particularly outdoor air-conditioning units, heat pump units, and swimming pool pumps. The Ontario Ministry of the Environment, Conservation and Parks (MOECP) document NPC-300 – Environmental Noise Guideline, and municipal noise bylaws cover a wide range of noise sources and situations. This article provides a simplified summary intended solely for general understanding. It is not legal advice. For full and accurate interpretation, readers should always refer to the original MOECP guidelines and applicable municipal bylaws.
Ontario Provincial Noise Guidelines
In Ontario, the Ministry of the Environment, Conservation and Parks (MOECP) provides guidance on environmental noise in the document NPC-300 – Environmental Noise Guideline: Stationary and Transportation Sources. Many municipalities base their noise bylaws on this guideline, although some municipalities modify or supplement it with local requirements.
What Is a “Stationary Source”?
NPC-300 defines a stationary source as:
“A source of sound or combination of sources of sound that are included and normally operated within the property lines of a facility and includes the premises of a person as one stationary source, unless the dominant source of sound on those premises is construction.”
In simple terms, this is a broad definition that covers most permanently installed equipment on a property, such as HVAC systems, provided that construction noise is not the primary sound source.
For residential noise complaints, outdoor air-conditioning units, heat pumps and pool pumps clearly fall within the definition of a stationary source, provided the sound is emitted beyond the property boundary.
Local variations to the definition of stationary sources
Most GTA municipalities follow the NPC-300 definition. Here is an example of a variation of the definition: Oakville defines a Stationary Source as:
“A source of sound, whether fixed or mobile, that exists or operates on the premises, property or facility, the combined sound levels of which are emitted beyond the property boundary of the premises, property or facility, unless the source is due to construction as defined in this By-law.”
This definition explicitly includes sound generated by backup or reverse alarms on vehicles operating on a property (with specific exclusions) and excludes certain qualitative noise sources, such as dog barking, noisy parties, domestic power tools, radios, and televisions.
Where Sound Is Measured?
Understanding where sound is measured is just as important as how loud it is, because measurements taken only a few metres apart can differ significantly.
All GTA cities use the concept of Point of Reception, meaning the point on a neighbouring property where the noise is received (e.g., the backyard near living areas). Toronto also specifically outlines examples, such as outdoor areas near a building façade.
What Is a “Point of Reception”?
Ontario’s MOECP NPC-300 – Stationary and Transportation Sources defines a "Point of Reception" as any location on a property where noise from a stationary source is received.
This typically includes outdoor areas of a neighbouring property where people may reasonably expect quiet enjoyment, such as backyards, patios, or near bedroom windows. In practical terms, this means that sound is assessed on the receiving property, not on the property where the equipment is located. Any location on the neighbouring premises where the noise is heard may qualify as a Point of Reception.
Local variations in the definition of the Point of Reception
The City of Markham distinguishes between:
- Points of Reception on the source property, and
- Points of Reception on a neighbouring (receiving) property
The Town of Oakville defines a Point of Reception as: “Any point on the premises of a person where sound originating from other than those premises is received.”
Both definitions align closely with the general intent of the MOECP NPC-300 and reinforce the principle that compliance is determined by the impact on the neighbour, not by the sound level at the source equipment.
Noise Limits in Urban Areas
The MOECP provincial guideline establishes noise exclusion limits for stationary sources in urban environments, referred to as Class 1 areas. These limits are based on time of day and are intended to protect nearby residents from excessive noise while allowing normal operation of equipment such as air conditioners and heat pumps.
Exclusion Limit Values of One-Hour Equivalent Sound Level (Leq dBA) Plane of Window of Noise Sensitive Spaces
Time of Day | Class 1 Area dBA |
|---|---|
07:00 - 19:00 | 50 |
19:00 - 23:00 | 50 |
23:00 - 07:00 | 45 |
Local variations to noise limits
The City of Toronto uses two-tiered limits as outlined in NPC-300 — quieter at night (45 dB) and slightly louder during the day (50 dB) — and also prevents equipment from exceeding the existing background noise level.
The City of Vaughan takes a different approach. For residential air conditioners, heat pumps, and similar devices, the bylaw states: "The noise level must not exceed 61 dBA when measured at the Point of Reception".
This limit applies specifically to residential HVAC equipment and does not vary by time of day. The bylaw was amended in September 2023 to confirm this requirement.
The City of Markham defaults to 50 dBA but allows an equipment’s noise to match the local background sound level if it is higher than the equipment's noise level.
Time-of-Day Rules
Toronto explicitly varies HVAC noise limits by time of day, with stricter limits at night. In Toronto, a heat pump that is 50 dB(A) during the day could be fine — but that same noise at 2 a.m. would have to be no louder than 45 dB(A) and not louder than the background sound around it.
Vaughan and Markham do not use different daytime/nighttime thresholds for their HVAC equipment limits — Vaughan uses a single fixed limit, and Markham ties to background levels, which naturally vary by time of day.
In Vaughan, the machine may be louder (up to 61 dB(A)) but must remain below that fixed level at all hours.
In Markham, if the background noise (e.g., from traffic) exceeds 50 dB(A), the unit may be louder up to that level; otherwise, it must remain at or below 50 dB(A).
How Is Noise From Air-Conditioning Units Tested?
To the best of our knowledge, most municipal noise bylaws do not prescribe a detailed test procedure for measuring noise from stationary sources, such as air-conditioning or heat-pump units. The MOECP NPC-103 procedure presumably applies.
While bylaws typically state a noise exclusion limit, they often do not explain:
In reviewing municipal noise bylaws across the GTA, it is not always clear that noise from residential air-conditioning or heat pump units is explicitly regulated under every general noise provision. In some cases, these units are not directly addressed, and provincial guidance under Ontario Ministry of the Environment (MOECP) documents is presumed to apply.
This can create uncertainty for homeowners, neighbours, and enforcement staff — particularly regarding how noise measurements should be conducted.
Use of NPC-103 Procedure
To address this issue, the MOECP publishes NPC-103 – Procedures, which is referenced by NPC-300. NPC-103 describes a short-duration measurement procedure that typically lasts only a few minutes, with the results extrapolated to an equivalent one-hour Leq.
This approach recognizes that:
- stationary equipment may not operate continuously, and
- short-term measurements, when properly conducted, can reasonably represent longer-term noise exposure.
As a result, many practitioners rely on NPC-103 procedures when assessing stationary-source noise, even when the municipal bylaw does not explicitly reference a test method.
The Meaning of “One-Hour Leq (dBA)”
Most municipal bylaws express noise limits in terms of One-Hour Leq (dBA), which represents the average sound energy over a one-hour period.
Taken literally, this would imply that:
For outdoor air-conditioning and heat pump units, this presents a practical challenge. These systems typically cycle on and off, operating for several minutes at a time. If measured over a full hour, the resulting average sound level may be significantly lower than the sound level produced while the equipment is actually running. This would not accurately represent the equipment's noise as perceived by people.
Use of the ASTM E1014 standard
Some acoustical consultants also follow the tet procedures outlined in ASTM E1014, a widely recognized standard for measuring outdoor noise from stationary sources.
ASTM E1014 provides guidance on:
While ASTM E1014 is not typically referenced directly in municipal bylaws, it is often used as a best-practice technical standard, particularly in professional noise assessments and expert reports.
In practice, noise testing for outdoor air-conditioning and heat pump units typically relies on factors such as:
can all affect whether a particular air conditioner or heat pump is considered compliant.
For this reason, proper assessment of HVAC noise complaints requires not only accurate sound measurements, but also a clear understanding of the specific municipal bylaw and how it applies the Point of Reception concept.
Because bylaws rarely specify detailed testing methods, professional judgment of an acoustical consultant and adherence to accepted standards are critical in determining whether a particular unit is likely to be considered compliant.
Key Takeaway for Clients
Across the GTA, outdoor air conditioners, heat pumps and pool pumps are generally regulated as stationary sources, but the allowable sound levels, measurement rules, and enforcement thresholds vary by municipality.
Some cities rely on:
As a result, the allowable sound level may vary depending on the measurement location, even for the same piece of equipment. This approach recognizes that noise impacts are generally more significant when sound is received on a neighbouring residential property rather than within the source property itself. A unit that complies in one municipality may not comply in another, even if the equipment and operating conditions are identical.
Sensitivity to noise is very individual. When a noise source is declared compliant with regulations, it does not mean it will not be annoying to some people. Sensitive individuals may complain about any noise, as discussed in this article on oversensitivity to noise.
