Seven key differences between a UPS system and an inverter

Faced with the gloomy prospect of load shedding until 2027, many South Africans have somewhat reluctantly realised the need for alternative energy-efficient power solutions.

Forget about insurance being a grudge purchase. Buying a reliable source of backup power has become something of an unwanted necessity for many of us.

There is simply no choice if you need to run a household, maintain a lifestyle or stay productive in the workplace. A source of backup power is crucial in these dark times.

We need a source of power to charge our mobile devices and run appliances such as washing machines, fridge-freezers and air conditioners – not only during scheduled load shedding but also during unplanned power outages.

For domestic and office users, in particular, the discussion about a source of backup power is usually about whether to invest in a UPS (uninterruptible power supply) system or an inverter to help them stay connected during a blackout.

These two solutions make up what is commonly known as backup power. By definition, backup power refers to any device that provides instantaneous uninterruptible power.

Both a UPS and inverter provide a backup supply to the electrical system. They are used for the same purpose.

However, there are some main differences between them. From the time it takes for them to start supplying power to the duration for which they can operate, to name but two.

Here are seven key differences between a UPS system and an inverter:

  • Description: Most notably, a UPS is designed to provide clean, stable power to critical loads in the event of other power sources failing or not being available. An inverter, on the other hand, is designed to convert DC power into standard AC power in order to charge and run equipment and appliances.
  • Application: A UPS is used mainly for computers and IT-related systems (such as routers) to provide electric power just long enough to enable you to save your data and shut down your computer when there is a power failure or load shedding kicks in. An inverter, on the other hand, typically provides power backup to various domestic and commercial electrical appliances such as fans, lamps and coolers.
  • Backup time: A UPS provides less backup time and therefore supplies power for a short duration. An inverter can supply power for much longer, depending on its capacity. Therefore an inverter supplies power for a longer duration.
  • Switching time: A UPS provides near-instantaneous power. An inverter, meanwhile, has a longer time delay before providing power.
  • Types: The types of UPS solutions available are:
    • Single Phase:
      • Off-Line UPS
      • Line Interactive UPS
      • On-Line UPS
    • Three Phase:
      • On-Line UPS

There are multiple types of inverters. These include:

    • Battery Backup Inverter Solutions
    • Inverters for Solar Solutions
    • Inverters with Generator Control
    • Grid Tied Inverters
    • DC Coupled Inverters
    • AC Coupled Inverters
    • Hybrid Inverters
    • Off Grid Inverters
    • Plug and Play Inverter Solutions
  • Connection: A UPS system is directly connected to the appliance, whereas the inverter is first connected to the battery and then connected to the circuit of the appliance.
  • Charging: A UPS can charge the battery from the main electrical supply. An inverter cannot charge a battery itself. It needs an external charge controller to charge the battery.
  • Read about more the differences between a UPS and an inverter


Since load shedding is here to stay for now, investing in a backup source of power is more important than ever. The cost, your power needs and your level of protection should be considered before making a decision to purchase a backup power solution.

  • Need some advice as to which backup power source you should purchase? Talk to us

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