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The Ultimate Guide to Buy the Right Generator

If you depend on your Generator as a back up power unit in the event of power outage or for your mobile business or for an event or even camping, you will know the importance of having the right generator for the job when you need it. There are numerous domestic as well as large scale applications of generators. At a glance it may seem extremely difficult to discover the generator that is perfect for your needs. This is precisely the reason why we have decided to shortlist necessary considerations and essential parameters that one should be vigilant of when buying a generator.

Identify Your Requirements

  • Application
    Since generators are meant for both domestic and industrial applications. You should know whether you are looking for one for backup power for homes, leisure use, or to power your factory.
  • Wattage
    It is essential you know exactly the type of load you need to run for which a power analysis should be done. Overloading a generator is the most common cause of failure and can cause damage to your appliances or the generator itself. Just as you would not run your car at maximum speed all day, it is the same for generators. Most appliances demand a higher current when they start, this is called surge. So your generator must have enough spare capacity to cope with that demand We have a handy calculator to help you work it out.
  • Fuel Type
    It is important to figure out the fuel type of the generator because it helps in estimating the fuel cost. There are wide-ranging fuel and cost -efficient diesel, LPG, and petrol generators that may lie within your range.
  • Load Type
    The nature of the load also impacts significantly over the type of generator. For instance, you may either need generator to power robust devices such as tools or for sensitive electronic equipment. If you are running sensitive electronics you will need an inverter generator or the electronics will be blown. Inverters produce higher quality AC current.

Electrical Usage

There are different types of generators even we are discussing domestic applications. A portable generator helps in running some applications but it will not be able to power the entire house. Portable generators can supply power from 1 KW to 15 KW and are used to power electrical machines, such as drills, saws, fans, lights and grinders. Ideal for construction or home improvement projects where there is no available electricity supply. Another kind of residential generator is a whole house back-up generator, also known as a standby generator which runs all the appliances in case of a power failure. Standby generators can supply power from 7 KW up to several hundred KWs. These generators enable you to use electricity completely independent of the electrical grid. You can operate house lighting as well as appliances effectively when there is a power cut-off.

Backup Power with a Transfer Switch

A transfer switch is also installed along with the generator. A manual transfer switch helps to switch from the utility power supplied by the grid to the backup power when you press a button. It is easy to use but you will have to locate the button yourself when there is a blackout. An automatic transfer switch (ATS) senses automatically when there is a power-cut and turns on by itself with minimal delay. When the utility power gets restored, it switches back to the grid power and shuts the generator off.

Backup Power With Switch

The backup generator powers the load when the power is cut

Power Requirements

It is important to figure out the power that you will need to power the appliances. Individual watts are specified on the electrical equipment. Some devices have additional starting watts that should be added to the total watts. The starting watts are found by multiplying the individual watts by 3. Also keep in mind that if your estimated total wattage is equal to 6000 watts, you head out and buy 6 KW generator. Generator KVA should be at least 20% greater than the estimated power.

Here are some of the appliances and their approximate watts to give you an idea about typical watts. However, you will have to assess your home or commercial requirements properly. The watts are specified on the equipment labels

Electrical Appliance Estimated Watts
Toaster 1050 - 1500
Vacuum Cleaner 1000 - 3000 + Starting watts (multiply individual watts by 3)
2 HP Motor 6000 (starting watts) and 2000 (operational watts)
1 HP Motor 3000 (starting watts) and 1000 (operational watts)

Water Heater

Iron 1000
Fridge 700 - 1000 (starting watts)

After you have figured out the watts, you will have to find a generator that meets these requirements. Generators are normally rated as KVA or KWs. To converts watts into KWs simply divide the total by 1000. However, to convert watts into KVA you will have to first covert watts into KWs and then divide by 0.8, which is the power factor.


– 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

Choosing from LPG, Diesel and Petrol Generators

In the UK, Honda, Hyundai, Kipor, Strom Swift Kraft, Güde GSE generators are extremely popular.

  • LPG: Liquid propane generators are connected to the main electric house panel and a fuelled by the liquid propane gas or natural gas. You may consider buying LPG generator if you want to buy a portable generator or standby home generator. LPG generators are cheaper to operate. LPG is gaining in popularity and is considered more ‘Green’.
  • Diesel: These generators are normally preferred for commercial applications as they are large in size. The run time of diesel generators is long and fuel economy is also good so the cost can be justified.
  • Petrol: Petrol generators can be used for domestic and commercial applications. Typically, these generators are available for power outputs of 1 KVA up till 10 KVA. Petrol is the most common fuel type, but bear in mind it can go off if it is stored for long periods of time.

Silent Generators

Most people prefer silent generators, which do not producing loud whirring noise. Silent generators reduce the noise to no more than that of the central air conditioning units. People who like to camp often, small business owners, large enterprises, and home owners buy standby silent generators. These generators also have long run times and keep the power supplied for long durations in case of a blackout.


Cold climate zone residents need generators for operating furnaces and other heat-producing devices when there is a power outage. On the other hand, people living in hurricane prone zones need power back up for outage caused by storms and tornadoes. Generators can supply power to areas when there is no power for weeks. A proactive investment will enable you to monitor the news in even of a disaster because you can watch television and charge your laptops.

Generator Pro provides high-quality, robust generators for domestic and commercial applications. We are a leading supplier of generators in the UK and have a stock of best first-class generators from top brands. Why not use our Generator selector tool or the first time buyers tool to find the right generator for you. For customer support and individual consultation contact us by calling at +44(0)800 980 3446 or 01342 713310. Our technical experts will discuss the specifications and requirements with you in depth to make sure that you are able to find the right product.