When your business relies on power, a good generator is a lifeline. But with so many models, brands, and fuel options available, choosing one can feel like a big task.
This guide breaks it down into simple, practical steps so you can make a confident decision based on your business’s real power needs.
1. Start with your power requirements
Before you even look at brands or prices, you need to know how much power your business actually uses. The easiest way to do this is to list every piece of equipment you’d want to keep running during an outage ( lights, servers, machinery, refrigeration, heating, security systems) and note their power ratings in kW or kVA.
If you only need to keep essentials running, a smaller standby generator might do the job. But if your business can’t afford any downtime, you’ll need a full-load generator that can handle peak demand.
A good rule of thumb:
- Office buildings: 50–200 kVA
- Retail units: 100–250 kVA
- Small manufacturing sites: 250–500 kVA
- Large industrial sites: 500 kVA and above
If you’re unsure, it’s worth asking a professional for a load assessment. PowerTech’s engineers, for example, can calculate the exact capacity you’ll need based on your daily usage and peak loads.
2. Choose the right fuel type
Industrial generators typically run on diesel, natural gas, or bi-fuel systems. Each has its own pros and cons depending on your location, usage, and budget.
Diesel generators
Diesel is the most common choice for industrial settings. These generators are powerful, reliable, and built to handle long hours of operation. Fuel is easy to store, and diesel engines are known for durability.
However, they do produce more emissions than gas units and can be noisy, so they’re better suited for outdoor installations or remote sites.
Best for: factories, farms, construction sites, and areas with unstable power supply.
Gas generators
Natural gas generators burn cleaner than diesel and are quieter too. They’re often connected directly to the gas mains, which means no need for on-site fuel storage. The trade-off is slightly lower output power and a higher upfront cost.
Best for: hospitals, data centres, and businesses in urban areas where gas lines are available.
Bi-fuel or hybrid systems
Some modern generators can switch between diesel and gas, offering flexibility and efficiency. They’re ideal for businesses that want lower emissions but still need the reliability of diesel backup.
Best for: mixed-use sites or organisations with sustainability targets.
3. Compare trusted generator brands
When you’re investing in a generator that may run for years, brand quality matters.
Let’s look at three of the most trusted ones:
FG Wilson
FG Wilson generators are known for solid engineering and consistent power performance. They’re a popular choice for commercial and industrial use, offering both diesel and gas models from 6.8 kVA to over 2,500 kVA.
Pros:
- Strong build quality
- Easy maintenance
- Wide range of sizes and configurations
Best for: businesses that want dependable standby power with low maintenance costs.
Cummins
Cummins is one of the biggest names in the power generation world. Their generators are designed for both heavy-duty and continuous use, with a reputation for efficiency and low emissions. Cummins units also come with advanced control systems for precise load management.
Pros:
- Excellent fuel efficiency
- Smart control options
- Global service network
Best for: businesses needing long-term performance and advanced monitoring features.
Perkins
Perkins engines are used in generators from many different manufacturers. They’re valued for their smooth running, easy servicing, and availability of spare parts worldwide. Perkins-powered units tend to be slightly quieter and are well-suited to mixed commercial environments.
Pros:
- Reliable and efficient engines
- Good fuel economy
- Widely available parts and support
Best for: SMEs or sites where consistent, quiet operation is essential.
Let’s say you run a food processing facility that can’t afford to lose refrigeration even for an hour. You’ll likely need a diesel generator around 400–600 kVA, installed outdoors with an acoustic enclosure.
If you run a small office or retail unit, a Perkins-powered 80–120 kVA diesel generator might be plenty. It’ll handle lights, tills, air conditioning, and security systems without breaking a sweat.
The key is matching the generator’s capacity to your critical load, not over or under-buying.
4. Think about installation and location
Where and how the generator is installed makes a big difference.
- Space: You’ll need enough room for the generator, exhaust systems, and ventilation.
- Noise: Check local noise regulations. Acoustic enclosures can reduce sound if you’re near homes or offices.
- Fuel access: Make sure refuelling or gas line connections are safe and accessible.
- Safety: Install on level ground with fire safety and emergency shut-off measures in place.
- Weather protection: Outdoor units should have canopies or shelters to protect them from rain, heat, and frost.
Professional installation ensures your system meets both electrical standards and environmental regulations.
For expert setup and long-term reliability,see our Generator Installation & Maintenance Services.
5. Plan for maintenance and servicing
Even the best generator won’t last without care. Regular maintenance keeps it efficient, extends lifespan, and prevents breakdowns during critical times.
Basic checks should include:
- Oil and filter changes
- Coolant and battery checks
- Load testing
- Exhaust system inspection
- Control panel calibration
Diesel generators generally need servicing every 250–500 hours of operation, while gas units can go slightly longer between checks.
It’s wise to work with a provider that offers a maintenance plan, including scheduled visits and 24-hour emergency support. PowerTech’s service packages cover new and used generators, giving you peace of mind long after purchase.
6. Think about the future
When you size your generator, consider not just today’s needs but where your business will be in three to five years. If you’re planning to expand production, add new equipment, or open another site, choose a unit that can handle a little extra load.
Oversizing by around 20% gives you flexibility without wasting fuel. A modular setup, using multiple smaller units that can be linked together, also makes it easy to scale up as your business grows.
Also read: How to Calculate What Size Generator You Need
7. New or used generators?
Buying a new generator gives you the latest technology, full warranty coverage, and often lower running costs. But used generators can be excellent value if they’ve been properly tested and refurbished.
PowerTech offers both options. Every used generator is fully inspected, serviced, and load-tested before sale. You’ll find detailed specifications, photos, and test reports online so you know exactly what you’re buying.
Upgrading your system? You can also Sell Your Generator to PowerTech for a fair, fast valuation.
Find your next generator with PowerTech
Generators are a long-term investment, and expert advice makes a world of difference. A good supplier will help you size it correctly, install it safely, and keep it performing for years.
At PowerTech, we specialise in supplying, installing, and maintaining both new and used industrial generators across the UK. We have a wide range of new and used generators from trusted brands like FG Wilson, Cummins, and Perkins.
Discover our full range of Generators for Commercial & Industrial Use. Tested, reliable, and ready to power your business.
FAQs
How do I know what generator size my business needs?
List every machine, light and tool you’ll run, then total their wattage or kVA. Always include a bit extra for startup surges and future growth. If that sounds tricky, PowerTech can do a quick site load test and tell you exactly what capacity you need so you don’t waste money on the wrong size.
What’s the difference between kVA and kW?
kW is usable power, kVA is the total power including inefficiencies. Most generators are rated in kVA. To estimate kW, multiply kVA by 0.8. For example, a 100 kVA unit gives around 80 kW of real output. Knowing this helps you match your load properly and avoid overloading or overspending.
Can I use the same generator for backup and everyday power?
Only if it’s rated for both. Standby generators are built for short bursts during power cuts. Prime-rated models are made to run for long periods or daily use. If you’re off-grid or running machinery often, go for a prime unit as it’s designed to handle the strain.
How long can a diesel generator run non-stop?
Most can run between 8 and 24 hours, depending on the tank and load. Larger industrial models with external tanks can go much longer. For long runs, you’ll need regular checks and refuelling breaks to prevent overheating or wear. Continuous use without servicing is never a good idea.
Are used industrial generators worth buying?
Yes, if they’ve been properly serviced and tested. A good used generator from PowerTech, for instance, comes fully inspected, load-tested, and with a report to prove it. Look for low operating hours and maintenance records, a used unit can be great value if it’s been looked after.
How noisy are industrial generators?
Most produce between 65 and 90 decibels, just like heavy traffic. You can cut that down with soundproof enclosures or barriers. If you’re in a built-up area, we can recommend low-noise models that meet UK noise limits without compromising performance.
What kind of base or foundation does a generator need?
A flat, solid concrete base with good drainage. It should be slightly wider than the generator and have anchor bolts to stop movement. For outdoor setups, weatherproof covers help extend lifespan. A proper base keeps the generator stable and reduces vibration.
How often should I service my generator?
At least once a year or every 250–500 hours of use. Servicing includes oil, filters, coolant, and a full test run. Regular maintenance keeps your generator efficient and ready when you need it. PowerTech offers flexible service plans for both standby and continuous-use units.
Can a generator safely power computers or medical equipment?
Yes, but it needs stable output. Go for a model with an automatic voltage regulator (AVR) or inverter control. These prevent voltage spikes that could damage sensitive kit. You can also use a UPS alongside it for total peace of mind.
What do I need to know before installation?
Installations must follow UK electrical and environmental rules, proper earthing, fuel storage, and ventilation are key. Always use certified professionals. PowerTech’s installation team handles everything from base prep to compliance checks so your generator runs safely and legally.