Last updated: 16/10/2022

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Whether at home, at work, when travelling or during a medical attendance, the fact is that electric power is essential. But what about when a power failure occurs? That is where the importance of generators comes in. And among so many models, one deserves your attention: The diesel generator.

Welcome to ReviewBox! In today’s article, we will show you what you should take into account when choosing the ideal diesel generator, whether for your home or business.


  • The diesel generator is essential equipment to ensure that the electric power is never interrupted.
  • Because of diesel, this type of generator is essential in industries and commerce, but can also be used in homes.
  • And as the variety of models is great, it is necessary to understand what differentiates a diesel generator from another

The Best Diesel Generators: Our Picks


Buying Guide

When buying a diesel generator, it is necessary to understand about its operation and the variables that differentiate one model from another. This is because, nowadays, there is an ideal generator for each objective.

For this reason, we have prepared this Buying Guide. Below, you will discover how and where to use a diesel generator, the price of this type of equipment and the best place to buy it.

Mulher pegando bebida em geladeira de comércio.

The generator can avoid losses in commerce in case of a power outage. (Source: Robert Nagy/

What is a diesel power generator?

A generator is a piece of equipment that provides uninterrupted power to premises and electronic appliances when a blackout occurs.

But there are several generators that, among other factors, are differentiated by the type of fuel they use to generate the required energy. One of them is the one that uses diesel.

The diesel generator offers uninterrupted energy.

The diesel generator offers uninterrupted energy. Therefore, it is most useful in homes, industries, small businesses, campgrounds and so on.

This is because the main characteristic of this type of generator is precisely the diesel, which is more economical.

Diesel is also more efficient in providing energy for long periods and not only when there is a power outage.

How does a diesel generator work?

A diesel generator works through a combustion engine, that is, it has an alternator that will transform the mechanical energy of the engine’s rotation into electric energy.

In practice, the air inside the generator is pulled until it is compressed, and then diesel is injected. With this combination, a strong heat is generated, which leads to the combustion of the diesel, making the generator work.

From this process, power is generated and distributed to the appliances connected to the generator.

What is the difference between diesel, gasoline and gas-powered generators?

As we have seen, a generator engine can run on different types of fuels. So it’s important that you understand the difference between them.

Generally speaking, each fuel will be more or less efficient according to the use you will make of the power generator.

For example, if you only use the equipment when there is a power failure at home, a gasoline generator may be the best option. But if the idea is to use the generator on a daily basis, the ideal model is a diesel-powered one.

This is because gasoline generators tend to be cheaper, quieter and less polluting.

Aeroporto sem energia elétrica.

The diesel generator is ideal to avoid inconveniences and damages in case of a blackout. (Source: Claudio Schwarz/

On the other hand, the diesel generator is more economical, since the fuel is cheaper. It is also a more durable piece of equipment than the gasoline-powered model.

In addition, there is the natural gas-powered generator, which is less used and even more expensive. This option emits far less pollutant gases, but offers a greater risk of fire.

To illustrate the differences between the diesel generator and the others, we have created the following table. Please see:

Diesel Gasoline Gas
Advantages More economical, efficient and durable Cheaper, quieter and less polluting Emits even less polluting gases
Disadvantages More expensive, larger and polluting Less economical and less efficient Risk of fire is higher

For whom is a diesel generator recommended?

As we have seen, due to its robustness, power and efficiency, the diesel generator is indicated for those who need to use the equipment constantly.

Therefore, it is essential in industries, shops and shopping malls, which may have serious losses if they are without power.

But because they can be used for hours, weeks or until the power supply is restored, diesel generators can also be used in homes and on farms.

Where to install a diesel generator?

It is important to take some care when installing the generator. The main one is not to leave the equipment in a closed place.

This is because during its operation, the diesel generator emits toxic gases, which can be harmful to health. In ventilated places, the damage is less.

Did you know that it is necessary to perform the maintenance of power generators periodically?

This is important to ensure correct operation and to avoid possible failures

What are the dangers of a diesel generator and how to protect yourself?

In addition to the care in the installation, to avoid intoxication, it is necessary to protect yourself from accidents, after all, diesel is an inflammable fuel.

The fact is that it is possible for a diesel generator to cause electric shocks and explosions. To avoid accidents and protect yourself, follow the instructions:

  • Make sure the engine is properly grounded to prevent electric shock
  • Keep the diesel generator away from combustible or other flammable mixtures;
  • Do not touch the generator while it is running, especially not if it or your hands are wet;
  • The equipment should not be run at full capacity;
  • To avoid accidents, the power generator must not exceed 20° of inclination;
  • The equipment must have its fuel tank isolated and its indicator lights working.

What are the advantages of a diesel power generator?

One of the advantages of a diesel generator is the low cost of the fuel. In addition, this device is ideal for those who need an efficient equipment that works for long periods.

Another positive point is that this type of generator has a more durable structure, which further increases its cost-benefit.

As it guarantees electric power for longer periods of time, the generator keeps electronic devices and home appliances such as TV, radio, computer, refrigerator and microwave oven running without any damage.

The biggest disadvantage of the diesel generator is the level of noise emitted by the equipment and the emission of pollutant gases.

To summarize the main advantages and disadvantages of a diesel generator, we have created the following table:

  • Guarantees electric power, without interruptions, even with blackouts
  • High power
  • Great efficiency and durability
  • Low fuel cost
  • Large, heavy and expensive
  • Noisy
  • Emits polluting gases

What is the price of the diesel generator?

The price of the diesel generator will depend on the brand, size and technical specifications of the equipment. But, generally, it is possible to find models that cost between £4 thousand and £45 thousand.

Purchase Criteria: How diesel generators compare

Now that you know how a diesel generator works and what it is used for, it is now time to find out what differentiates one model from another.

We have listed for you the main aspects that should be taken into account. They are the following

From here on, we will explain how to assess these items.


Check the voltage of the place where the diesel generator will be used. This is because the voltage of the equipment should be chosen according to the voltage of the appliances that the generator will serve in case of blackout. When in doubt, opt for a bivolt generator.

Power and sizing

Next, analyze the power of the diesel generator, measured in kVa (kilovoltampere). To choose the ideal you should calculate the sizing, which is how much is expected from the consumption of your generator.

To do so, follow the step by step below:

  • Make a list of all the appliances that can be connected to the generator;
  • Add up the wattages of all the appliances;
  • Divide the total power of the equipment by 1,000;
  • There you go, the result will tell you the value of the kVA needed for the diesel generator.

For example: If you add 2,000 Watts from a microwave, with 3,000 Watts from an electric grill, 1,000 Watts from an electric shower and 3.5,000 Watts from a clothes dryer, the total of 9.5,000 Watts divided by 1,000 will result in 9.5 kVA.

Remember that the higher the power of the generator, the higher the fuel consumption will be.

Single-phase, two-phase or three-phase

Both the voltage analysis and the sizing are also important when choosing the power supply mode of the diesel generator, which can be single-, two- or three-phase.

In the single-phase generator, for example, the power supply is only efficient for networks of, at most, 127 V and for a power of up to 8,000 watts.

The generator also varies according to its supply capacity.

The two-phase power supply, on the other hand, can have electrical voltages of 127 V or 220 V. In addition, the supply capacity of this type of generator ranges from 12,000 watts to 25,000 watts.

In the case of the three-phase generator, the voltage can also be 127 V or 220 V, but the capacity ranges from 25,000 watts to 75,000 watts.


If you want to avoid as much as possible that the appliances connected to the diesel generator can burn out, you should ensure that the equipment has a good voltage regulator.

The regulator is responsible for making sure that the power reaching the appliances is constant, making it so that the equipment can be turned on more safely.

In this regard, the best is that the generator comes with the AVR (Automatic Voltage Regulator). It is this that will leave the network stable, similar to the electrical network.

Tank and autonomy

Another criterion that we recommend you take into account when buying the best diesel generator is the autonomy of the device. The autonomy is the period of time that the generator can work without needing to be refueled.

Generally speaking, diesel generators are designed to provide between 5 and 10 hours of continuous power.

But to get it right, you need to consider that the range depends on the size of the fuel tank. Therefore, you will find diesel generators with a tank capacity ranging from 4 to 25 litres.

(Image source: Henadzi Pechan/