FAQs

Got questions about generators, hire, compliance or servicing? Find quick answers below, organised by topic.

Can you retrofit acoustic treatment to an existing enclosure

Often yes. Options depend on the existing enclosure design and the target noise reduction. Common retrofit measures: upgrading inlet/outlet attenuators, adding acoustic absorption lining, improving door and access panel seals, fitting a higher-performance exhaust silencer, and installing anti-vibration mounts. Contact us with details of your unit and noise target for a feasibility assessment.

How does acoustic packaging affect ventilation and cooling

This is the central challenge of acoustic design. Every cubic metre of air the generator consumes for combustion and cooling must enter and exit through openings — and every opening is a potential noise path. We design inlet and outlet attenuators (baffled silencer sections within the airflow) to reduce noise without restricting airflow below what the engine needs. Getting this wrong causes insufficient noise attenuation or engine overheating — neither is acceptable. iPower models both acoustic and thermal performance for every enclosure we design.

Can iPower achieve better than 65 dB(A) at 1 metre if...

Yes. Our 65 dB(A) at 1 metre is our routinely achieved standard performance for units up to 550 kVA. Where planning or site sensitivity demands lower noise levels, we can engineer to tighter targets — but this involves more complex attenuation, potentially powered ventilation, and increased cost. There is always a trade-off between acoustic performance, thermal performance and cost. We will be transparent about what is achievable and at what price.

What dB(A) level will a planning authority typically require

Common conditions in residential or semi-urban areas target 45–55 dB(A) at the nearest noise-sensitive receptor (a neighbour's boundary or window). Working back from that target depends on the distance and any natural barriers. In a typical suburban installation 20 metres from the boundary, you might need 60–65 dB(A) at 1 metre from the enclosure. In dense urban sites, stricter requirements may apply. iPower designs to the specific planning condition for your site.

What does dB(A) actually mean

dB(A) is sound pressure level weighted to reflect human hearing sensitivity across frequencies. The (A) weighting reduces contribution from very low and very high frequencies and emphasises the midrange where hearing is most acute. It is the standard measurement for environmental noise assessments, planning conditions and generator specifications. Every 10 dB increase represents a doubling of perceived loudness — so 75 dB(A) sounds roughly twice as loud as 65 dB(A), even though the number is only 10 more. Sound pressure level varies under the inverse square, so that every doubling or halving of distance from the rated distance will give a 6dBA decrease or increase (respectively) to the rated sound pressure.

MYTH: More acoustic lining inside the enclosure equals...

To a point. Increasing absorption material reduces reflected noise, but there are rapidly diminishing returns. The biggest gains come from treating the ventilation openings and the vibration path from generator to enclosure. Beyond a certain point, more lining delivers minimal further reduction while adding weight and cost. Good acoustic design targets where noise is actually escaping — which is almost always the ventilation, not the walls.

MYTH: dB(A) figures from different manufacturers are...

Not always. Noise levels depend heavily on measurement conditions — distance, reflective surfaces, and whether the test was free field (open air) or semi-reverberant. Some manufacturers measure at 7 metres; others in an anechoic chamber that bears no resemblance to a real site. iPower quotes real-world figures at 1 metre based on free field (non reflective) performance. When comparing specifications, always check the measurement distance and test conditions before comparing numbers.

MYTH: The exhaust is the main noise source. TRUE OR FALSE

Partly true, but incomplete. The exhaust is often the loudest single source on a bare engine, but a proper exhaust silencer typically reduces exhaust noise below the mechanical and combustion noise of the engine block. Once that's done, the dominant noise sources are: mechanical noise from the engine and alternator (structure-borne and airborne), cooling airflow through ventilation openings, and radiated noise from enclosure panels. All need to be addressed. A good exhaust silencer alone will not achieve 65 dB(A).

MYTH: Bigger enclosures are always quieter. TRUE OR FALSE

Not necessarily. Size helps in that it provides more distance from the noise source to the enclosure wall, and more room for acoustic lining. But the critical acoustic paths are almost always the ventilation apertures, not the walls — and those are governed by airflow physics, not enclosure volume. A well-designed compact enclosure with properly attenuated ventilation will outperform a large but poorly designed one. Acoustic performance is about engineering, not square footage.

MYTH: I can put my generator in a shipping container and...

False — at least without significant acoustic treatment. A standard ISO container is a steel box with no acoustic absorption and provides perhaps 10–15 dB of attenuation at best. It will also act as a resonant cavity that amplifies certain frequencies. Without proper acoustic lining, attenuated ventilation apertures, vibration isolation from the floor and a correctly silenced exhaust, a containerised generator can actually be noisier than a well-canopied unit. iPower builds acoustically treated containerised solutions when warranted — but they require the same engineering rigour as any other acoustic solution.

MYTH: An acoustic canopy is just a metal box. TRUE OR FALSE

False. A proper acoustic enclosure is an engineered system. The enclosure itself must be lined with acoustic absorption material, but the bigger challenge is ventilation. A generator produces enormous heat and needs a large volume of cooling air — typically 10–30 cubic metres per second for a large unit. Every cubic metre that enters and exits the enclosure is a potential noise leak. Inlet and outlet attenuators must be sized to reduce noise without restricting airflow to the point where the engine overheats. Getting this balance right is an engineering exercise, not a metalwork one.

MYTH: A quieter engine means I don't need a proper...

False. There is no such thing as a quiet diesel engine at generator scale. Combustion, mechanical vibration and exhaust noise from any bare diesel generator are significant — typically 95–110 dB(A) at 1 metre. Engine manufacturers can reduce this to perhaps 80–85 dB(A) with a basic factory canopy, but achieving 65 dB(A) or below requires a purpose-engineered acoustic enclosure with proper absorption lining, vibration isolation, attenuated inlet and outlet ventilation, and a correctly designed exhaust silencer. There are no shortcuts.

What is acoustic packaging for a generator

Acoustic packaging — also called a sound-attenuated canopy or acoustic enclosure — is a purpose-built housing designed to contain and reduce the noise produced by a generator set. iPower manufactures its own range of acoustic canopies in Dungannon, built to project specification. We routinely achieve 65 dB(A) at 1 metre for units up to 550 kVA, and 75 dB(A) at 1 metre for 1 MVA installations.