Generator Buyers Guide: Which Generator Should I Order?

Here at SGS we have a wide variety of generators for a number of domestic and commercial applications, so we understand that finding the perfecting one for your requirements might seem daunting at first. We’ve spent some time putting together a simple check-list of considerations to help you narrow the choices.

Working out what you need

 

  • Wattage – determine exactly how much power you’ll require for the items you wish to run.
  • Domestic or professional – some generators are designed specifically for hobbyists and leisure use, others are perfect for workshops and commercial use.
  • Equipment – do you want to run sensitive equipment such as computers or televisions straight from your generator? We have a range of inverter generators for sensitive electronics.
  • Petrol or diesel – you need to consider the total cost of ownership when investing in a new generator. With a comprehensive petrol and diesel generator range, you’ll be able to pick the most cost efficient fuel source for your power requirements.

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Your total required wattage

blenderAll of our generators are rated to run at a certain wattage. The first thing you must consider is what wattage you need your generator to produce to power the equipment you wish to run. Regardless of whether you’re going to be running camping equipment or a whole construction site, this is a vital step in the buying process – otherwise you might end up with a generator that isn’t fit for purpose.

  1. You can find the individual wattages of an item on the equipment itself, in the user manual, on a manufacturer’s website, or by contacting the manufacturer by phone.
  2. What items do you want to run together? For example, if you want to run a slow cooker and a fan at the same time, you need the combined wattage of the equipment. If you’ll only ever run each item independently, then you just need to worry about the item with the highest wattage.
  3. Do the items have a starting wattage? Any piece of equipment with an induction motor will have a starting wattage, and therefore a higher wattage requirement. This includes chop saws, air compressors, vacuum cleaners, pressure washers, and freezers - anything with a motor in it. Simply multiple the items wattage by three to find it’s starting wattage.
  4. Give yourself some headroom. Just because your car can go 120 miles an hour, it doesn’t mean that it’s suitable to drive at the maximum all the time. Your generator will be very much the same; a 4200W generator shouldn’t be used to power 4200 watts worth of equipment. Give yourself at least 20% head room.

So your final required wattage is:

All the individual equipment wattages for the items you wish to run together (x 3 if the item has an induction motor), + 20% head room = minimum wattage generator you require

For example, to run a 250W slow cooker with a 650W hand drill the maths is:

650W (drill) x 3 (starting wattage) = 1950W

1950W (drill total) + 250W (slow cooker) = 2200W

2200W + 20% = 2640W total required watts required

Typical Power Ratings

 

This is an approximate guide only. Wattages can vary massively, so it's always worth looking up your specific piece of equipment.

Electrical Equipment Approximate Wattage Electrical Equipment Approximate Wattage
Air con 1hp 2500* Iron 1000
Angle grinder 125mm 1100* Iron (steam) 2200
Angle grinder 230mm 2200* Jigsaw 600*
Belt sander 1100* Kettle 2500 - 3000
Cement mixer (small) 1500* Lawn mower 600 - 1200*
Central heating pump 800 Lawn raker 500
Chain saw 1600* Light bulb-domestic 25 - 100
Concreate poker 2500* Microwave 900W 1500
Cooker 12,000 (minimum)* Orbital sander 500*
Computer and VDU 700 Planer 1000*
Coffee machine 1300 Power drill 500 - 900*
Dehumidifier 3000* Power float 1500
Deep freeze 1500* Photocopier 1600
Demolition breaker 2400* Pressure washer 3000 - 6000*
Dish Washer 2000 - 3000* Printer 400
Fan heater 2 bar 2000* Radiator (oil filled) 1000 -2000
Fax Machine 600 Router 1600 - 9000*
Flood light TH 500 Saw (chain) 1500*
Flood light MH 1000 Saw (masonry) 4000*
Fluorescent tube 60 Saw (mitre) 1600*
Floor sander (200mm) 2000* SAT TV receiver 25
Food mixer 500* Strimmer 500*
Fridge 700 - 1000* Television 200
Hair dryer 1500 -2300* Toaster 1050 - 1500
Hair straightners 150 Treadmill (domestic) 2300*
Hammer drill 1000* Tumble dryer 2500*
Hedge trimmer 600* Vacuum Cleaner 1000 - 1300*
Hi-fi 300 Washing Machine 4000*
Hot air gun 3000 Water heater 3000
Electrical Equipment Running Watts Starting Watts
0.25 HP motor 250 800
0.50 HP motor 500 1600
0.75 HP motor 750 2300
1.00 HP motor 1000 3000
1.50 HP motor 1500 4500
2.00 HP motor 2000 6000

*These items will normally have a starting wattage so remember to multiply the wattage by 3.

kVA, kW and Watts:

Now we know the total watts required to run our equipment, we need to match it up with a generator. Generators are often listed in kVA (kilo-volt-amps) or kW (kilo-watts). These are both measurements of power, so just slightly different numbers for the same thing. To convert Watts (W) to KiloWatts (kW) divide by 1000 - Eg. 1000W = 1kW To convert KiloWatts (kW) to Kilo-volr-amps (kVA) divide by 0.8 – Eg. 1000W = 1kW = 1.25kVA Now we know the total watts required to run our equipment, we need to match it up with a generator.

Generators are often listed in kVA (kilo-volt-amps) or kW (kilo-watts). These are both measurements of power,  just in slightly different formats. 

   - To convert Watts (W) to KiloWatts (kW) divide by 1000 - Eg. 1000W = 1kW
   - To convert KiloWatts (kW) to Kilo-volt-amps (kVA) divide by 0.8 – Eg. 1000W = 1kW = 1.25kVA

Domestic or Professional Use?

We split our range of generators in two ranges; domestic and professional use – each with their own warranty specific to its intended use.

If you want a generator for doing occasional jobs requiring power tools, for your hobby, or as a short back-up generator for outages, a SGS generator will be exactly what you’re looking for. SGS generators are fantastic value for money and perfect for home and hobbyist use. Designed to be run occasional, they are perfect for back up use or working in the garden at the weekend.

If you’re planning to use the generator every day or commercially, we have a whole range of generators perfect for the task. If you need a power source regularly, or for a prolonged period of time, we’d suggest a Stephill generator. They’re made in the UK to the highest of standards, with energy efficiency and performance in mind. They’re fitted with Honda, Yanmar or Lombardini engines and come with a three year commercial use warranty.

We also offer a range of budget Hyundai generators that are perfect for lower end commercial use and serious hobbyists. They’re great for backup power or more sporadic commercial applications.

Electrically Sensitive Equipment?

Anything with a microprocessor in it is considered sensitive to electrical power, meaning computers, phones, TVs, games consoles, printers, DVD players and even some kitchen appliances and power tools, shouldn't be run directly from a conventional generator.  A simple solution is to run them from an inverter generator to prevent damaging them. These generators "invert" DC power back into AC power, resulting in a much "cleaner" power (pure sine waves).

We have a range of our own inverter generators, as well as some powerful Honda and Hyundai inverter generators. View Now

Petrol or Diesel Generators?

Choosing between a petrol or diesel generator may seem arbitrary, but in reality it will seriously affect your total cost of ownership. Diesel generator tend to cost more out of the box than petrol alternatives, but when you think about the long term running costs it’s not quiet that simple. Over the long term, diesel will give you a considerable saving on fuel if you’re using the generator often, especially if you have access to red diesel. Diesel engines require less maintenance and will generally stand up to more regular use, especially with high end engines and generator models. As a rule of thumb, it you’re looking for a generator under 10 kVA then you would purchase a petrol model, and over 10 kVa you would look at diesel generators. Choosing between a petrol or diesel generator may seem arbitrary, but in reality it will seriously affect your total cost of ownership. Diesel generators tend to cost more out of the box than petrol alternatives, but when you think about the long term running costs it’s not quite that simple.

Over the long term, diesel will give you a considerable saving on fuel if you’re using the generator often, especially if you have access to red diesel. Diesel engines will generally stand up to more regular use, especially with high end engines and generator models.

As a rule of thumb, it you’re looking for a generator under 10 kVA then you would purchase a petrol model, and over 10 kVa you would look at diesel generators.

 SPG3200  

Petrol Generators

Petrol generators come in 1 to 10 kVA models and are available as great value domestic use models as well as professional models design for high usage. Available in 110 and 230V sockets, you would also need a fly lead for use with a standard 3 pin plug. View Now

 SE3000D  

Diesel Generators

Diesel generators tend to be larger and are more expensive than petrol generators. However, they offer better fuel economy and longer run times. Large capacity diesel generators (10kVA+) are available, such as "welfare cabin" models. We have diesel generators available made by Stephill here in the UK, as well as by Hyundai. View Now

Standby Generators

There’s nothing more frustrating and disruptive to a busy life than a long power outage. Waiting around in the dark and being completely reliant on the National Grid can be quite the headache – but there is a cost effective solution! Standby generators allow you to use your household lighting and appliances in the home, completely independently of the grid, meaning you’re always prepared for a power-cut.

The simplest way of providing back up power to your home is to install two products; a standby generator and a transfer switch.

transfer switch Manual Power Transfer – A manual transfer switch (MTS) allows you to switch between utility power and backup power at the touch of a button. They’re simple to use and relatively easy to install – the only drawback is that you might have to find the switch in the dark if you have a power-cut at night!

Automatic Power Transfer – With an automatic transfer switch (ATS), the process is even simpler; the ATS senses when the power goes down and automatically starts the generator. Within a few seconds your home has power again and you can continue your day as normal. When the primary power for the home is restored the ATS will switch back to utility power and shut down the generator, leaving it in a standby state, until it’s needed again.

 

dhy6000se-main_2As well as providing you with convenience and security, a stand-by generator power system can reduce home-owners insurance rate and even boost the value of your house. You can see a full range of SGS standby generators here. Beware; installing a standby generator and/ or a transfer switch should only ever be carried out by a competent electrician. View Now

Specialist Generators

As our range of generators has grown over the years, we’ve added more and more specialist generators. As well as a comprehensive range of petrol, diesel and inverter generators we now stock a range of LPG, welder, rail approved, welfare and export generators, to suit more specialist requirements.

 SE2700-LPG-with-tank  

LPG Generators

Bottled gas offers a considerable saving compared to petrol or diesel fuel sources. On average LPG is 30% - 50% cheaper to run, and as the price of petrol and diesel steadily increase, an LPG generator becomes an ever more attractive solution. If you’ve got LPG gas canisters readily available, like many caravan enthusiasts do, the LPG range can be a great mobile power solution. View Now

 SW200AC  

Welder Generators

Stephill offer a small range of generators specifically designed for the welders. They’re rugged, purpose built generators made in the UK, perfect for commercial use on site.  We also offer a range of compatible welding leads in AC and DC varieties. View Now

 RT2700HMC  

Rail Approved Generators

Here at SGS, we’re one of the few suppliers of Network Rail approved generators in the UK. Designed to be robust, dynamic and overall incredibly safe to work with, these specialist generators are perfect for commercial use around and on the railway. View Now

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Welfare Generators

These specifically designed diesel generators are great for powering accommodation or welfare units. They’re all made in the UK and powered by super-silent Yanmar and Kubota engines. They’re simple to use, single phase, low vibration units available with delivery straight to site. View Now

 6500HMS-2  

Export Generators

Specifically designed for operation outside of the UK, these export generators offer great value for money, considering their impressive power output. Made by Stephill in the UK, they all come with 3 years' commercial warranty and an unparalleled build quality. View Now

Still not sure which generator to choose?

SGS Engineering are the UK based experts in generators. As well as designing our own range of generators, we’ve stocked some of the biggest brands around, so we really know what we’re talking about. Call us today for unbeaten customer support and advice. Our technical team are available for individual consultation, so call on 01332 576 850 to discuss your requirements today.