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Open Frame Vs Closed Frame Generators

What’s the difference between open frame and closed frame generators? Read this blog post to know the exact answer.

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If you’re looking for a new generator, you’ve certainly noticed there are countless variations available: portable, standby, standard, inverter, open frame, closed frame, dual fuel, and more. It’s easy to become lost in all the terminology. Fortunately, professionals at BISON can help you out.

Today we will focus on the difference between open-frame and closed-frame generators. Both types of generators provide quieter, cleaner power compared to conventional generators. However, there are a few things to consider when deciding whether an open-frame or closed-frame generator is right for you.

Open frame generators

Open generators are the most common solution on the market. They have two significant advantages: low cost and quick access to internal components. The open design consists of a solid metal frame welded from hollow metal tubes. Its main task is to secure the motor and alternator, preventing them from loosening during work.

The frame is also used as a transport handle for low-power models. It can be fixed to the floor with suitable metal brackets – this will ensure the generator’s high degree of stability, even when working under maximum load.

Advantages of open frame generators

Open enclosure design

Open enclosure design provides unobstructed access to key plant components for quick equipment maintenance. In addition, no obstacles are created for effective heat dissipation, almost eliminating overheating;


Simple design and no need for additional enclosures make open-frame models more affordable than closed-frame models.

Lighter weight

Available in a lighter design version. This indicator is especially important for low-power models, which are often carried by hand, such as in country houses, mobile outlets, etc.

Disadvantages of open frame generators

High noise

No additional noise protection. There is significant acoustic discomfort when operating near people or for long periods at night.

Fragility of components

Despite the metal frame, the unit, alternator, and other components are not protected from all kinds of mechanical damage. Also, since high humidity from precipitation can negatively affect the device, it should not be run under open skies for extended periods of time.

Generator ignition coil display-2

Closed frame generators

Closed frame generators are enclosed in soundproof enclosures and are also common on the market. But they are a more powerful solution with a complete set of features and advantages compared to open frame generators. A significant advantage is that the noise level is reduced by 15-20 decibels, which significantly improves the acoustic performance of the device during operation.

The main difference between an enclosed generator and an open generator is the presence of a casing. It is made in the form of a solid perforated metal structure with several layers of soundproofing material inside. The type and number of layers of sound-absorbing material directly depend on the generator’s manufacturer and model. Generally, the more expensive the model, the higher the quality of the enclosure and the more soundproofing.

Advantages of closed frame generators

Quiet operation

The high-quality soundproof enclosure reduces noise levels by 15-20 dB and, in some cases, 30dB. They are ideal for use in residential premises: summer houses, private houses, villas, etc. The noise level of low-power devices is only 40 decibels, which is comparable to that of ordinary washing machines.

Alternator and motor protection

Frames serve as additional protection for internal components from mechanical damage.

Longer lifetime

Not only from mechanical damage but also from moisture, dust, and wind due to higher protection of internal components.

Disadvantages of closed frame generators

High cost

Due to the presence of additional housing elements, closed frame generators will cost more than open units.

Possibility of overheating

Additional sound insulation automatically reduces the cooling quality of the device. If not appropriately operated or maintained on time, the generator can overheat, leading to unpleasant consequences until it fails.


Comparison: Open frame vs. closed frame generators

Noise levels

The main difference between open and closed inverter generators is noise. Closed-frame generators will run quieter than their open-frame counterparts.

A closed-frame inverter generator usually produces about 57 decibels (dBA), while a similarly sized open-frame generator produces about 67 dBA.

Engine access

An open-frame generator is like a traditional one because the body design exposes the engine. This makes maintenance more manageable as the engine is more accessible.

The closed frame completely encloses the engine. It better protects the unit from external forces like dust and wind. Furthermore, this design difference is the main reason for the difference in noise levels between the two styles.

Price point

In general, closed-frame inverters tend to run on the higher cost side. If you’re on a tighter budget but still want a generator’s clean, low THD power, an open-frame model might be the way to go. However, if you plan to use the generator for hunting, camping, or any other application that requires low noise levels, it may be worth spending a little extra on a model with a closed frame.

Conclusion: Open frame vs. closed frame generators

In the end, your demands will determine which generator is best for you, including the type of equipment you want to power, how much power you need, acceptable noise levels, and more.

But no matter what you need, BISON has the generator for you. If you need assistance selecting the best generator for your needs, please email [email protected] to talk to our friendly and knowledgeable technical support team.

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