The Difference Between UPS and Inverter: Understanding the Power Backup Systems

Dial A Contractor
Go to content

The Difference Between UPS and Inverter: Understanding the Power Backup Systems

Leading Construction and Building Group
Published by Francois Heyns in Power Backup Systems · Tuesday 14 Feb 2023
Tags: invertorupsPowerBackupSystemseskomblackouts

Electricity has become an essential part of our daily lives, powering various appliances from laptops to electric cookers, mobile phones, and more. However, when the power goes out unexpectedly, it can cause a great deal of disorder. To ensure uninterrupted electrical power supply during a blackout, power backup systems like UPS and inverter have been developed. Although these systems serve the same purpose, people often remain confused about the difference between them. In this article, we will highlight the differences between UPS and inverter, helping you make better use of them.

How do UPS and Inverters Work?


A UPS, or Uninterrupted Power Supply, is designed to stop the interruption caused by a power blackout to electronic devices like computers. The system consists of a rectifier that converts AC into DC to charge the battery. The battery is then connected to the inverter, which converts the DC back into AC. A controller is provided to manage the system's functioning.

UPS is mainly intended for IT systems and electronic devices that can get damaged with sudden power out conditions. It provides power supply for up to 10-15 minutes.


An inverter, on the other hand, is a power electronic device used to convert DC to AC. AC power supply is taken from AC mains and converted into DC by a rectifier. This converted DC charges a battery. As the industrial and household systems work on AC power, the DC from the battery is converted into AC by the inverter. During a power cut, the inverter receives supply from the battery and provides power supply to the electrical equipment. These systems are used in the household to get the power supply after the blackout of electricity. No external power supply is needed for the inverter to work.

Key Differences Between UPS and Inverter

Use Case & Backup Time

  • If you don’t have frequent power cuts, a UPS is an ideal solution to safeguard your computer from any major hardware failure. The switch to UPS is almost instant, and this doesn’t shut down your computer. UPS typically offers a backup of around 30 minutes or so.
  • The switching of UPS from the mains supply to the battery is immediate, whereas the inverter takes more time. For computers, the switching time of the inverter is more than it can handle, and it will usually reboot due to the interrupted supply. Thus, UPS is preferred for PC and inverter for homes as lightbulbs will not care about the switching delay.
  • UPS can provide backup for your devices for around 15 minutes, whereas an inverter can provide backup for hours depending on its capacity. The inverter allows you to power the complete house depending on the capacity. So if your area has a more extended power cut, you can use it to keep a couple of lights and fans running.

Maintenance & Lifespan

  • UPS is maintenance-free, while inverters need more wiring and require distilled water to be filled at regular intervals. However, some advanced versions of inverters have freed consumers from distilled water maintenance.
  • The disadvantage of UPS is that since the battery is continuously being charged and discharged even when there’s no power cut, the battery will wear out 4-5 times quicker than the inverter battery.


  • Compared to inverters, UPS is cheaper. There are different types of UPS and inverters available, and they are available at competitive prices.
  • The factors to look into when buying them include backup time, capacity, charging time, power requirement, crating (quantity of charge in a fully charged cell), and warranties.

Other Differences

  • UPS has a rectifier for providing the backup power to the system, whereas the inverter converts DC into AC.
  • The main function of the UPS is to store electric supply, whereas the inverter converts AC power into DC power.
  • During power outages, the UPS immediately switches over from the main supply to the battery, whereas the inverter has a time delay.
  • The UPS provides electrical backup power, and the inverter provides electronic backup power supply.
  • The offline, online, and line interruptive are the types of UPS, whereas the inverter is of two types, i.e., the standby inverter and grid tie inverter.
  • The UPS is directly connected to home appliances, whereas the inverter is first linked to the battery and then attached to the appliance circuit.
  • The UPS is more expensive than the inverter.
  • The rectifier and battery are inbuilt in the circuit of UPS. The rectifier converts the AC into DC and stores the energy into the battery, whereas the inverter has an external battery for storing the DC power.
  • The UPS provides backup supply for a very short duration, whereas the inverter supplies power for an extended period.
  • The UPS does not have voltage fluctuation because its input is independent of the output supply, whereas the inverter has voltage variation.
  • The UPS is used for domestic purposes, in offices, and industries, whereas the inverter is used in the office.

How Dial a Contractor Can Help

Whether you are looking for a UPS or inverter for your home or office in Cape Town, Durban, Pretoria, or Johannesburg, Dial a Contractor can help you. Our expert team of electricians can provide you with the best power backup solutions based on your specific needs and budget. We can help you choose the right type of UPS or inverter, install it, and provide maintenance services to ensure it works efficiently for years to come.


UPS and inverter are two different devices that serve the same purpose of providing power backup in case of power outages. While UPS is ideal for IT systems and electronic devices that can get damaged with sudden power outages, an inverter is better suited for households as it provides power for an extended period. UPS is cheaper and maintenance-free, but the battery wears out faster. Inverters need more wiring and require distilled water to be filled regularly, but they provide longer backup times. Understanding the key differences between the two devices can help you choose the right power backup system for your needs. Contact Dial a Contractor for professional advice and installation of power backup systems in Cape Town, Durban, Pretoria, or Johannesburg.

Back to content