Silent vs Open Type Diesel Generator: Choosing the Right Enclosure
By Tommy, Export Sales Manager at Zhiqiang Power · tommy@zhiqiang-power.com · Last reviewed 2026-09-17 against factory load-bank data
The enclosure is the cheapest decision to get right and the most expensive to fix later. It decides where the set can physically sit on your site, what your neighbors will hear, and how a technician will reach the filters on service day.
The short answer
Order an open skid when the set lives in a dedicated engine room or shelter; order a silent canopy when people work or sleep within about ten metres of it. The canopy decision must be made before the build, because it cannot be added later.
- ›Open type: lowest cost, best cooling airflow, easiest maintenance access, needs a weather shelter or engine room.
- ›Silent canopy: steel enclosure with rockwool lining and a residential muffler, typically 68–75 dBA at 7 metres depending on size.
- ›Containerized (ISO 20ft / 40ft container housing): the usual answer above about 500 kW outdoors, with walk-in service space.
- ›Retrofitting a canopy onto an open set means redoing exhaust, cooling airflow and lifting points, so it rarely saves money.
When an open skid is the right call
If the generator goes into a purpose-built engine room, a mine workshop or a farm shed where noise is already tolerated and airflow is adequate, the open skid gives you the most machine per dollar. Everything is reachable: oil filters, injectors, the alternator terminal box. The trade-offs are exposure (it needs a roof) and noise (typically well above 90 dBA at 7 m without a muffler enclosure).
When the silent canopy pays for itself
Hospitals, hotels, offices, resorts and any urban plot with a boundary close to the set need the canopy. Our canopies use heavy galvanized steel, rockwool acoustic insulation and a residential-grade muffler, landing in the 68–75 dBA range at 7 metres depending on the power class. Plan for the extra footprint, the louvre airflow path and the canopy doors opening fully for service.
Containerized sets for the megawatt class
Above roughly 500 kW, an ISO 20ft or 40ft container becomes the practical choice outdoors: it ships as one lift-ready unit, walks a technician inside, and integrates the fuel tank, switchgear and sometimes the transformer room. Mining camps and island power stations mostly order this way.
Related reading
Power ratings follow ISO 8528-1:2018 (Prime PRP / Standby ESP), and the fuel figures are stated at ISO 3046-1:2002 standard reference conditions. Both are confirmed unit by unit on our load bank, and the test record ships with the set. Standby figures are the engine's factory standby rating from the model spectrum table — never a computed 110% of the rated output. Noise figures are typical open-type reference values, not a guaranteed sound-power level.
Frequently Asked Questions
How noisy is a silent type diesel generator?▼
Typically 68–75 dBA measured at 7 metres, depending on the power class and canopy design. For comparison, an open set of the same size sits well above 90 dBA at the same distance. The exact figure for each canopy we build is printed on the datasheet that ships with the set.
Can I add a soundproof canopy to an open generator later?▼
In theory yes, in practice it rarely pays. The exhaust routing, radiator airflow, lifting points and door access all change with a canopy, so a retrofit costs more than ordering the set enclosed from the start. Decide the enclosure when you place the order.
Which type do hospitals and hotels need?▼
Silent canopy, and in dense urban sites sometimes a containerized acoustic solution. Hospitals also want the standby rating, an AMF panel for automatic start on mains failure, and a fuel tank sized for the outage duration they plan for.
Get a technical quotation for your project
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