UPS vs. Inverter: What is the difference?

Did you know? One of the first things Andre de Ruyter did in his position as Eskom CEO, was to order a paint job for the main board room at Megawatt Park, reported Businesstech.

The fact that he didn’t want to work in a “dirty and shoddy-looking” environment says a lot about the man’s meticulous nature, but we are still not seeing light at the end of the Eskom tunnel. 

That is, of course, because the power is off. We have no choice but to make a different plan.

ups vs inverter 1

The case for solar power

Load-shedding and cable theft are not the only power-related problems we are facing. The effects of climate change and global warming are becoming a very real concern.

Global warming today is happening at a much faster pace than ever before, and we are to blame. 

“Natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades,” NASA said last year.

Finding a way to produce electricity with reduced carbon emissions is not really optional anymore, and the good news is that it will, in time, boost your bottom line.

In fact, more than 100 of the Fortune 500 companies have already benefited from switching to solar, including the likes of Walmart, Target, Apple and IKEA.

Here at home, brands like Anglo Platinum, Makro and the City of Joburg have also taken steps to go green and break free from Eskom, and these companies are seeing a difference in their utility bills.

Businesses can reduce their overall energy costs by up to 75% by opting for renewable energy. Yes, there will be a significant investment needed from you to get your solar system installed.

However, once it is paid off, you have free electricity for the lifetime of your solar system – and this could be over 30 years. And there is no better place to do it than here in sunny SA.

10 things to know and questions to ask before going solar

  1. Establish the amount of energy your home or business uses every month. Remember to include future changes in your energy use, such as new family members.
    This will help with planning the number of solar panels and the size of the solar system you will need.
  1. Ask whether the type of roof you have might affect the cost of installation. You might also want to consider the condition of your roof and whether it needs any repairs.
  1. Find out how much extra you will have to pay for insurance to ensure that your solar system is covered as well.
  1. Do you want to go completely off-grid, or do you still want to be connected to the grid? This decision will also affect the cost of your system.
  1. Find out if there are warranties in place for the products you choose to purchase.
  1. Choose a trusted contractor to handle your installation. It’s always worthwhile to do some research on your chosen company and see what kind of reviews they get.
  1. You needn’t be too concerned about cloudy days, as your panels will still work, in the same way you can still get sunburned on cloudy days.
    Rain has the benefit of cleaning dust and debris that can block the sun from your panels.
  1. Ask about the maintenance required to keep your system functioning optimally. Generally solar panels don’t require much maintenance, but best to ensure that you can do any upkeep that is required.
  1. What type of solar panels should you get? Your chosen solar company will advise, but there’s no harm in doing your own reading to better your understanding.
  1. Ask whether there are any problems that have occurred in the past with your chosen solar system.

Components of a solar system

Going solar is a bit more elaborate than slapping some solar panels on the roof. 

You will have components such as the panels, mounting racks, possibly a backup generator, batteries, an inverter and perhaps a UPS (uninterruptible power supply), among others.

How does it all fit together? For the purposes of this article we will take a closer look at the inverter and the UPS, both of which provide backup supply to your electrical system.

An inverter allows you to continue using various appliances in the event of a power failure. The main function of the inverter is to convert direct current power (DC) into alternating current (AC).

The inverter is usually powered by batteries, which, in turn, can be charged by solar panels or other conventional sources of power supply.

There are different types of inverters on the market: 

  • String inverters. Solar panels are installed in rows, each of which is on a ‘string’.
    Multiple strings can be connected to one string inverter. The solar panels produce DC power which is carried to the inverter via the string.
  • Central inverters. They are larger and can support more strings of panels.
    With string converters the strings run directly into the inverter, but here they are connected together in a common combiner box that runs the DC power into the central inverter. 
  • Microinverters. If you are making use of these, you will have a microinverter installed on each of your solar panels.
    They convert DC power to AC power right there at the panel, so you won’t need a string inverter.
    This also has the added bonus that the overall performance of your solar panels won’t be affected by one panel that might be underperforming due to being in the shade.
  • Battery based inverter. These are bi-directional, include both a battery charger and an inverter and need a battery to operate. They provide for continuous operation of critical load irrespective of the condition of the grid.
inverter installation 1

The main function of a UPS is to provide protection when the main power source is lost. Your computer, for example, will keep running if the power goes off unexpectedly, but only for a short time. 

This gives you time to save what you were working on and shut down the computer in a proper manner.

Apart from power failures, the UPS also protects your appliances from these common power problems: 

  • Power sag/low voltage issues.
  • Power surges.
  • Under voltage and over voltage. 
  • Electrical line noise.
  • Frequency variation. 
  • Switching transient – instant under-voltage happening within nanoseconds.
  • Harmonic distortion – distortion of a normal power wave, typically transmitted by unequal loads.

As with inverters, there are different types of UPS:

  • Offline/standby UPS. This is the most basic UPS, and works well for computers.
  • Online/double conversion UPS. The most reliable option that offers the best protection.
  • Line-interactive UPS. Reliable and efficient, but with a lower electricity consumption, making it more cost-effective.

One of the most significant differences between UPS and inverter is that the UPS switches from the main supply to battery instantly, while the inverter takes time to do the same thing.

9 differences between a UPS and inverter

The experts at identified the following key differences between the UPS and inverter:  

  1. The UPS is an electric device that has a rectifier for providing the backup power to the system, whereas the inverter converts DC into AC.
  1. The main function of the UPS is to store the electric supply whereas the inverter converts the AC power into DC power.
  1. The UPS provides the electrical backup power, and the inverter provides the electronics backup power supply.
  1. Each of the two devices are available in different types. You get an offline, online and line interruptive UPS, and two types of inverter: standby and grid-tie.
  1. The UPS is directly connected to the home appliances whereas the inverter is first linked to the battery and then attached to the appliances circuit.
  1. The UPS is more expensive as compared to the inverter.
  1. The rectifier and battery are built into the circuit of UPS.
    The rectifier converts the AC into DC and stores the energy in the battery, whereas the inverter has an external battery for storing the DC power.
  1. The UPS provides the backup supply for a very short time, whereas the inverter supplies power for a longer period.
  1. The UPS does not have voltage fluctuation because their input is independent of the output supply, whereas the inverter has voltage variation.

UPS vs inverter: what should you get?

According to some sources a home inverter can be seen as just an offline UPS system. 

This means that the load is usually fed by mains 220V AC power, and when the power fails, the inverter switches on and runs off the connected battery to supply AC power. 

The inverter switches off when AC mains power returns.

A home inverter is typically fitted with a big rectifier so that it can charge big backup batteries for long discharge run times. This is the same thing as a UPS with extended backup battery charger.

Generally speaking a UPS is more expensive than an inverter, and they come with the possibility of a slightly higher electricity bill.

A UPS is necessary in applications where continuous power is needed, but if you don’t necessarily need that, an inverter with external batteries is the more cost-effective option. 


When it comes to powering your home or business, you have to consider a few different ways of doing things.

The easiest solution is always to know exactly what your needs are. This empowers you to get only that, and not waste money on extras.

Know somebody that can benefit if you share it with them?


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