Updated:04 November 2026
Rank 1-11 of the best Diesel Generators
Our recommendation Price Customer rating
1. Comparison winner
WITKOWSKI KDE8500DP 8.5 kVA Diesel Generator
WITKOWSKI KDE8500DP 8.5 kVA Diesel Generator
Available immediately
free shipping
Our rating
9,8
very good
No reviews yet
KS 9300DE-1/3 ATSR Diesel Generator, 7,500 W, 400/230 V
KS 9300DE-1/3 ATSR Diesel Generator, 7,500 W, 400/230 V
Available immediately
free shipping
Our rating
9,6
very good
3. Bestseller
Hyundai 7.5kVA/5.8kW Diesel Generator (230V/400V), Electric Start, Long Runtime, Portable
Hyundai 7.5kVA/5.8kW Diesel Generator (230V/400V), Electric Start, Long Runtime, Portable
Available immediately
free shipping
  • Runtime: up to 30 hours on a full 25 litre fuel tank
  • Noise level: 70 dB at 7 metres
  • Fuel consumption: approximately 1 litre of diesel per hour
Our rating
9,6
very good
Warrior 12.5kVa Diesel Generator, Model 296cc, Electric Start
Warrior 12.5kVa Diesel Generator, Model 296cc, Electric Start
Available immediately
free shipping
  • up to 24 hours of running time with 60-litre tank at 50% load
Our rating
9,6
very good
No reviews yet
5. Best value
Stephill SSD6000S 6.0kVA Ultra Silent Diesel Generator
Stephill SSD6000S 6.0kVA Ultra Silent Diesel Generator
Available immediately
free shipping
  • Runtime 17.0 hours at 75% load
  • Noise level 59 dBA at 7 metres
  • Start mechanism key start for quick ignition
Our rating
9,6
very good
No reviews yet
Könner & Söhnen KS 9200HDES-1/3 Power Generator, 18HP Diesel Engine
Könner & Söhnen KS 9200HDES-1/3 Power Generator, 18HP Diesel Engine
Available immediately
free shipping
  • continuous operation time at 50% power: 11.1 hours
  • noise level measured at 7m: 69 dB
  • engine is diesel-powered with a fuel tank capacity of 20 litres
Our rating
9,5
very good
Warrior 6.25kVa Diesel Generator, Model 186cc, Electric Start
Warrior 6.25kVa Diesel Generator, Model 186cc, Electric Start
Available immediately
free shipping
  • up to 12 hours run time at 50% load with 16-litre fuel tank
  • designed with soundproof canopy and anti-vibration mountings offering quiet operation
  • features wireless remote start and key start facility for easy starting
Our rating
9,0
good
Silent Diesel Generator 6kVA/6500W, Single-Phase 230V with ATS, 115V/230V Electric Start, Closed-Frame, 4-Wheel Portable, 20L Fuel, Tool Kit and Funnel
Silent Diesel Generator 6kVA/6500W, Single-Phase 230V with ATS, 115V/230V Electric Start, Closed-Frame, 4-Wheel Portable, 20L Fuel, Tool Kit and Funnel
Available immediately
free shipping
  • up to 16.5 hours of operation on a full 20 litre fuel tank
  • low noise operation thanks to a soundproof canopy
  • automatic transfer switch provides instant back-up power; optional electric start allows manual ignition if preferred
Our rating
8,9
good
Hyundai Silenced Standby Diesel Generator 5.2kW/6.5kVA, Electric Start, Single Phase, Low-noise Canopy, 13L Fuel Tank
Hyundai Silenced Standby Diesel Generator 5.2kW/6.5kVA, Electric Start, Single Phase, Low-noise Canopy, 13L Fuel Tank
Available immediately
free shipping
  • Up to sixteen hours of runtime with a thirteen litre fuel tank at fifty per cent load
  • Quiet operation with a sound attenuated canopy to reduce noise for domestic use
  • Electric start for easy engine starting
Our rating
8,8
good
Portable Diesel Generator 5kVA 10HP
Portable Diesel Generator 5kVA 10HP
Available immediately
free shipping
  • provides power for up to 14 hours with a 12.5-litre tank
  • noise level of 77 decibels at a 7-metre distance
  • optional electric start for easy manual operation
Our rating
8,4
good
Neilsen CT1848 3kW Diesel Generator, 230V
Neilsen CT1848 3kW Diesel Generator, 230V
Available immediately
free shipping
  • 10 hours of continuous operation
  • Low noise level for quieter use
  • Efficient fuel consumption for extended running time
Our rating
7,5
satisfactory

Similar Diesel Generator comparisons

Diesel Generators buying guide: How to choose the right product from the above Diesel Generators test or comparison

Understanding Diesel Generators: The Basics We All Need to Know

What is a Diesel Generator?

A diesel generator is essentially a combination of a diesel engine and an electrical generator. Its primary function is to convert diesel fuel into electrical energy, which is especially useful when electricity from the grid isn’t available or reliable. We often see these generators powering construction sites, emergency backup for businesses, and even rural areas where the power supply is inconsistent.

Why Choose Diesel?

Diesel generators are known for their robustness and efficiency. Diesel fuel is more energy-dense than petrol, meaning these generators provide longer runtime per litre of fuel. If we need a reliable solution for continuous power, especially in critical situations like hospitals or telecommunications, diesel generators often stand out. They typically have a longer lifespan than petrol generators, which makes them a wise investment.

Key Features to Consider When Choosing a Diesel Generator

Power Output

When selecting a diesel generator, one of the first features to evaluate is its power output, measured in kilowatts (kW). It’s essential to match the generator’s output with our needs. For example, a small generator might suffice for basic appliances like lights and refrigerators, whereas larger setups are necessary for workshops or industrial use.

Fuel Efficiency

Fuel efficiency is another crucial factor. Some generators consume more fuel than others for the same output, which directly impacts our operating costs. Look for models that maximise fuel efficiency to save money in the long run.

Maintenance Requirements

Each generator model comes with different maintenance needs. It’s essential to consider how often we might need to service the unit and the ease of finding replacement parts. Choosing a model with straightforward maintenance can significantly reduce operational headaches.

Noise Levels

Noise can be a significant concern, especially in residential areas or during night-time operations. Generators are available with varying noise levels; hence, if we’re sensitive to sound, it’s wise to pick a quieter model.

Sizing Your Diesel Generator: How to Determine the Right Power Output

Calculating Total Wattage Needs

To determine the right size generator, we need to first calculate our total wattage requirements. Start by listing all the devices we intend to power simultaneously and their respective wattages. This helps in avoiding the common pitfall of under-sizing the generator, which can lead to power shortages.

Understanding Starting vs Running Watts

It’s also worth noting that some appliances, particularly those with electric motors, require a higher starting wattage than their running wattage. Understanding the difference between these watts ensures we choose a generator capable of handling both initial starts and continuous operation.

Portability and Installation: What We Should Look Out For

Weight and Mobility

Portability is a significant consideration, particularly if we need to move the generator frequently. We should evaluate the weight and whether it has wheels or handles for easy transport. For instance, if we plan to use the generator at different job sites or events, a lightweight and portable model is beneficial.

Installation Requirements

Installation can vary significantly from one model to the next. Some diesel generators can be easily set up with minimal tools, while others may require professional installation, especially if they need to be connected directly to the electrical system. Understanding the installation requirements upfront can help us avoid unexpected costs.

Maintenance Tips for Your Diesel Generator: Ensuring Longevity and Reliability

Regular Checks and Servicing

To keep our diesel generator running smoothly, regular checks are essential. This includes monitoring fluid levels, such as oil and coolant, and ensuring filters are clean. We should establish a routine inspection schedule to maintain optimal performance.

Fuel Considerations

Using high-quality diesel fuel can make a significant difference in the generator’s performance. Poor quality or contaminated fuel can lead to clogs and reduced efficiency. Always ensure we store diesel in proper conditions to avoid any degradation.

Storage Practices

If we don’t anticipate using the generator for an extended period, it’s crucial to follow specific storage practices. This includes draining the fuel system, checking the battery, and storing it in a dry, cool environment. Proper storage will prolong the life of the generator and ensure it’s ready for use when needed.

Table of contents
  1. Understanding Diesel Generators: The Basics We All Need to Know
  2. Key Features to Consider When Choosing a Diesel Generator
  3. Sizing Your Diesel Generator: How to Determine the Right Power Output
  4. Portability and Installation: What We Should Look Out For
  5. Maintenance Tips for Your Diesel Generator: Ensuring Longevity and Reliability

Overview

1. Comparison winner
WITKOWSKI KDE8500DP 8.5 kVA Diesel Generator
Our rating
9,8
very good
No reviews yet
WITKOWSKI KDE8500DP 8.5 kVA Diesel GeneratorAvailable immediately
KS 9300DE-1/3 ATSR Diesel Generator, 7,500 W, 400/230 V
Our rating
9,6
very good
KS 9300DE-1/3 ATSR Diesel Generator, 7,500 W, 400/230 VAvailable immediately
3. Bestseller
Hyundai 7.5kVA/5.8kW Diesel Generator (230V/400V), Electric Start, Long Runtime, Portable
Our rating
9,6
very good
Hyundai 7.5kVA/5.8kW Diesel Generator (230V/400V), Electric Start, Long Runtime, PortableAvailable immediately
Warrior 12.5kVa Diesel Generator, Model 296cc, Electric Start
Our rating
9,6
very good
No reviews yet
Warrior 12.5kVa Diesel Generator, Model 296cc, Electric StartAvailable immediately
5. Best value
Stephill SSD6000S 6.0kVA Ultra Silent Diesel Generator
Our rating
9,6
very good
No reviews yet
Stephill SSD6000S 6.0kVA Ultra Silent Diesel GeneratorAvailable immediately
Könner & Söhnen KS 9200HDES-1/3 Power Generator, 18HP Diesel Engine
Our rating
9,5
very good
Könner & Söhnen KS 9200HDES-1/3 Power Generator, 18HP Diesel EngineAvailable immediately
Warrior 6.25kVa Diesel Generator, Model 186cc, Electric Start
Our rating
9,0
good
Warrior 6.25kVa Diesel Generator, Model 186cc, Electric StartAvailable immediately
Silent Diesel Generator 6kVA/6500W, Single-Phase 230V with ATS, 115V/230V Electric Start, Closed-Frame, 4-Wheel Portable, 20L Fuel, Tool Kit and Funnel
Our rating
8,9
good
Silent Diesel Generator 6kVA/6500W, Single-Phase 230V with ATS, 115V/230V Electric Start, Closed-Frame, 4-Wheel Portable, 20L Fuel, Tool Kit and FunnelAvailable immediately
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Our tests and comparisons are objective and fact-based. Manufacturers have no influence on the ratings. We aim to provide greater transparency in the market, thereby promoting product quality.
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In our tests & comparison tables, we only include products that meet our minimum standards. This ensures that you can find the perfect product for your needs from a wide selection.
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