How to Choose Between a Surge Protector and a UPS for Your Mac

| MGG Answers


How to Choose UPS vs Surge Protector Mac

Ernesto writes: I’m about to purchase a new 27-inch iMac to replace my current 24-inch model from a few years ago. I have many devices attached to my current iMac that I will migrate to the new one, including speakers, external hard drives, powered USB hubs, and an external Blu-ray drive. Everything is connected to power via several standard surge protectors that are about five years old.

As I prepare to set up my new Mac, would you recommend that I keep the existing surge protectors, swap them out for new ones, or use something like an uninterruptible power supply (UPS)? What benefit does a UPS provide over standard surge protectors other than battery backup?


To start, let’s identify the difference between standard surge protectors and a UPS. Surge protectors provide protection by dissipating any excess power (surges) and preventing it from reaching your connected devices. Electronic equipment, especially sensitive equipment such as a computer or a hard drive, is designed to operate within a certain power range. If too much voltage reaches a device, it can permanently damage or destroy it.

APC UPSAn example of a consumer-grade UPS from APC.

A UPS provides protection against surges as well, but also includes a built-in battery with varying capacity based on model. Many people recognize the benefit of a UPS as providing extra power in the event of a blackout, giving a user time to save their work and shut down or keeping a computer running throughout the blackout if the UPS battery is large enough or the blackout lasts only a short time.

However, the use of a battery also means that the devices connected to a properly-functioning UPS will receive steady voltage and current in the event of a brownout or blackout. In simplistic terms, the UPS receives electricity from the wall, passes it through the battery, and then feeds it to connected devices. Because the battery is technically powering the devices at all times, the power levels are delivered in proper and steady amounts, regardless of what happens to the power coming from the wall.

A surge protector can therefore be thought of as providing protection from excessive levels of electricity only, while a UPS provides protection from both excessive and insufficient levels of electricity. This, of course, is in addition to the benefit of keeping a computer functional during a power loss.

Those interested in purchasing a UPS should note that not every outlet provides battery backup power. Many UPS devices, especially those targeted at consumers, only provide battery backup (and thus the benefits of both high and low power regulation) via one or two outlets. The rest of the outlets provide only surge protection. Therefore, read the technical specifications of a UPS carefully before purchasing to ensure that it will meet your needs and take care in setting it up so that your most critical devices are attached to battery-backup outlets.

Another factor to consider is financial compensation. Many surge protectors and UPS systems come with limited insurance policies offered by the manufacturer. If a surge protector or UPS is properly configured and connected to appropriate devices, the manufacturer will compensate you for any equipment damaged or destroyed in the event of a surge protector or UPS failure, or in the event of more serious power surges that overwhelm the capacity of the unit.

The manufacturer's liability is limited to a set dollar amount and only applies in certain situations, but the added value of an insurance policy is an important factor to consider when making a purchasing decision.

In summary, surge protectors are a minimum requirement for all important electronic equipment. Those with the ability to add a UPS to their computer setup should strongly consider doing so, especially if the user lives in an area prone to electrical issue. While neither a surge protector nor a UPS will provide complete protection against devastating events such as a direct lightning strike, using one will give your electronics and computers the best chance at a long, trouble-free life.

If only this edition of Mac Geek Gab Answers had been available to the engineers at the Superdome on Sunday night…

Teaser graphic made with help from Shutterstock.

This question was originally answered on MGG 434: The Calm Before The Storm

About MGG Answers:

Each week Dave Hamilton and John F. Braun provide some great troubleshooting advice to listeners of the Mac Geek Gab podcast. Here with MGG Answers we share some of those tips with the rest of the world!

Popular TMO Stories



Some UPSs pass power through the battery and provide regulation, but not all do. For example, some will provide power if utility power is cut but won’t compensate for low voltage. More expensive ones will adjust for too-high or too-low voltage.

So check carefully and match the UPS model to your needs.

Lee Dronick

There is another difference to consider when deciding between a surge protector and a UPS.

If I understand it correctly, as the slight power surges that come through on a daily basis the surge protector uses up its buffer. Eventually it will not be protecting from surges, but becomes simply a power strip. The user thinks that they are being protected when indeed they are not. Now I may incorrect about that and if so I will admit it, but I learned that from an electrical engineer.

One other thing. I have a UPS for my modem, Airport, and MicroCell. If there is a power outage that affects cell towers I may still be able to make calls via the MicroCell and the internet. I still have POTS, traditional telephone service, that almost always works during blackouts, but I am considering canceling it.


Lee - I remember hearing the discussion about “using up” surge protection.

I have more recently seen discussion that says that newer surge protectors use different electrical components and so do not suffer the deterioration. But I haven’t seen anything definitive, and maybe both kinds are still available at different price points (similar to the situation with voltage correction in UPSs).

Can anyone contribute up-to-date information?

Lee Dronick

“Can anyone contribute up-to-date information?”

Well my information goes back to the days of Apple II and an electrical engineer who was a guest speaker at our user group. That is why I included a disclaimer. smile

Yes there may be difference in the technology used and the price of the surge protecter. I see some home surge protectors approaching the price of a UPS

Another thing to look for in a UPS is one that has a silence alarm switch feature. I can usually tell when the power is out and don’t need the UPS beeping at me like a smoke detector with a low battery.


UPS is great, but they sure as hell weigh a lot.
Surprising someone hasn’t figured out a lighter technology.


Airzone är en av de ledande varumärkena på den nordiska marknaden inom saneringteknik. Vi har ett sortiment av ozongeneratorer som vi själva har utvecklat som med fördel kan användas för att sanera olika typer av lukt och mögel.

Abhishek Mukherjee

There is some talk about using a UPS that produces a true sine wave. Supposedly the Mac power supply needs it. Cheaper UPS devices produce a simulated sine wave which could harm the power supply. I don’t know what kind of harm it may produce. In my research, I have found the APC Back-UPS to have the simulated sine wave which is not recommended. The APC Smart-UPS (previously APC-SUA) seems to produce a proper sine wave.

Also, the 27inch iMac needs 365W of power. I don’t know if this holds true for the late 2013 models with the Haswell chips (which need less power). So, when buying a UPS, be sure to get something that produces more than 600W of power to give you ample time to back up before the battery runs out.

Scott Waschlerner

Thank you for such useful information! In our area the surges are very common thing and sometimes they are enought to turn off the computer. I decided to buy UPS.  And as see APC is the most qualitative one. I have found APC model here and I want to order it. But tell me please can I connect to it more than one computer?

Log in to comment (TMO, Twitter or Facebook) or Register for a TMO account