UPS vs Inverter: Which One Do You Need for Load-Shedding?

Load-shedding interrupts work, drops video calls and can corrupt files when a computer loses power without warning. A UPS and an inverter both help, but they are built for different situations. This guide explains the difference and helps you choose the right one for your home or office.

What Is a UPS?

A UPS (uninterruptible power supply) is a box with a built-in battery. Equipment plugs into it, and when the power fails it switches to battery within milliseconds, so your computer does not even blink. It also protects against surges and dips. A UPS is designed to give you minutes to a few hours of power for low-wattage equipment, enough to save your work and shut down safely, or to keep a router and a laptop running through a short outage.

What Is an Inverter?

An inverter converts the power stored in a separate battery (or battery bank) into mains power. Because the battery is separate, you can use a much larger one and run equipment for hours. Many inverters are hybrid and can also take solar panels, so the batteries recharge during the day. An inverter system suits longer outages and a wider range of devices, including lights, TVs, routers and computers.

UPS vs Inverter: The Main Differences

• Switch-over: a UPS switches instantly, so computers keep running. Some inverters have a short switch-over delay, so check this if you plan to power desktop computers directly from one.
• Runtime: a UPS gives minutes to a few hours. An inverter with a large battery can run for many hours.
• Cost: a small UPS is cheaper to start with. A full inverter system costs more but covers more of the house or office.
• Best for: a UPS protects one desk or one rack of equipment. An inverter covers circuits, lights and several devices.
• Maintenance: both rely on batteries that wear out over several years and need to be replaced.

What to Protect First

Start with the devices that matter most and use little power:

• Router and fibre equipment: they draw very little power, and keeping them online means you can keep working on a laptop battery or by phone.
• Desktop computers: a power cut shuts down a desktop instantly. A UPS gives time to save and shut down. See our desktops and all-in-one PCs.
• CCTV recorder and cameras: a security system is least useful when the power is out. See CCTV and security.
• Point-of-sale equipment: keep the terminal, card machine and router running so you can keep trading. See point-of-sale equipment.

Avoid connecting heaters, kettles, geysers and stoves. They use far too much power for a UPS, and for most inverter systems.

How to Size a UPS or Inverter

1. List each device you want to keep running and note its power in watts (usually on its label or power supply).
2. Add the numbers together, and choose a unit rated comfortably above the total.
3. Decide how many minutes or hours you need. Longer runtimes need a bigger battery.

UPS capacity is often listed in VA, and the usable watts are typically 60 to 70% of the VA rating, so allow for that. Devices that use extra power when they start, such as fridges and pumps, need extra headroom on an inverter.

Do You Need Either If You Use a Laptop?

A laptop has its own battery, so it keeps running during a short outage. Your router and fibre box, however, will not. A small UPS or inverter for the router is often the most useful purchase. If you rely on a laptop during outages, also look after its battery. See our guides on laptops for working through load-shedding and laptop battery care, and browse replacement laptop batteries and chargers.

Where to Start

Browse our UPS units and inverters, and keep your connection going with networking equipment. If you are unsure what size you need, contact us with a list of the devices you want to protect and we will help you choose.