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Back in the day, Symantec and McAfee were the industry leaders in providing paid antivirus solutions. Running free antivirus programs for assured protection was considered questionable.

Then, Microsoft released Security Essentials, included for free starting with Windows 7. Independent lab test scores increased with each passing month. Windows users gradually began forgoing paid subscriptions for their antivirus needs. Around the time Windows Defender replaced MSE on Windows 8, however, the scores started to suffer. It got so bad that in 2013, Microsoft itself recommended users use something else.

Nowadays, not only are free antivirus programs viable — market growth having spurred healthy competition among vendors to best each other’s lab test scores — we even recommend them over paid options for protecting your students’ computers.

Free vs. Paid Antivirus Solutions

The benefits of paying for antivirus typically include telephone technical support, parental controls, and a much better detection rate of zero-day malware — threats whose signatures have yet to be analyzed because they are so new. (Antivirus software relies upon patterns of signatures to identify malware for inclusion in virus definitions.)

Since the learner population you deal with consists mostly of low-income users, chances are their computers are not that fast. Because of this, free antivirus programs are more than ideal — they take up less disk space and consume less resources (paid offerings tend to include non-antivirus components such as a firewall and internet security).

Reputation Is Important

Installing a free antivirus product is only practical if it’s from a reputable company. NQ Mobile, for example, inflates metrics to enhance perception of legitimacy to further their ulterior motive of distributing spyware — malware that enables a user to covertly steal your data.

Others, like Qihoo, have been around since 2005 but are still prone to unethically cheating AV-Comparatives tests — by supplying a custom scanner that used a Bitdefender engine — even after Anonymous Analytics, a division of the Anonymous hacker collective, published a 2013 paper revealing that they regularly overstated volume of traffic in order to attract advertisers.

Finally, some products themselves are outright malware — Anvisoft’s founder was exposed to be none other than elite hacker Wicked Rose, leader of the Chinese state-sponsored hacker group NCPH.

Criteria for Our Recommendations

When considering the best free options, the factors we considered, in order of priority, were

  • System resource usage
  • Malware detection rate
  • Frequency of pop-ups

All of our recommendations are developed by reputable companies, light on system resource usage, capable of detecting at least 99 percent of post-zero-day threats that paid software is capable of detecting, with minimal intrusions prompting the user to upgrade.

Bitdefender Antivirus Free Edition

Bitdefender Antivirus Free Edition is developed and maintained by a Romanian company founded in 2001. It scored the highest of all our recommendations in threat detection. It is able to protect against an astounding 100 percent of AV-TEST’s zero-day threats, and 99.9 percent of both AV-TEST’s and AV-Comparatives’ real-world tests.

BAFE uses approximately 11 to 16 MB of RAM when idling (for comparison, AVG, which we do not recommend, uses three times that much) and less than 200 MB of disk space.

In order to stay protected beyond the 30 days given upon installation, the learner has to create an account by clicking the Bitdefender system tray icon and then the Create a new account link.

Bitdefender create a new account link

Bitdefender new account window

A confirmation link is sent by email, so the email address provided must be a working one that the learner can access.

Avira Free Antivirus

Avira Free Antivirus is offered by a German company founded in 1986. It scored 5.5/6 for protection on AV-TEST, uses around 7.6 MB of RAM while idling, and occupies less than 300 MB of disk space.

In the past, you had to uncheck boxes like adding the Ask toolbar during installation and uninstall its browser extension afterward. Now, you can skip all of the bloat components from a single window after Avira Free Antivirus is installed (still annoying but consolidated).

clicking the Skip link


One notable feature of Avira Free Antivirus is its cloud-based security. Operations like threat signature analyses don’t consume your local computing resources because they are performed on Avira’s servers.

Avast Free Antivirus

Avast Free Antivirus is produced by a Czech company founded in 1988. It scored 6/6 for protection on AV-TEST, uses an average of 7.3 MB of RAM idling, and occupies 1.36 GB of disk space.

Avast main window


Free registration is required for protection beyond 30 days, giving the user a 12-month license, which can be renewed annually for free. Avast seems to be following Avira’s lead, recently announcing “From now on, we’ll be running a significant portion of our analysis in the Cloud — and not on your system where it can slow you down.” They acquired AVG earlier this month to enhance its mobile protection solutions.


Panda Free Antivirus 

Panda Free Antivirus is offered by a Spanish company founded in 1990. It scored 6/6 for protection on AV-TEST, occupies less than 150 MB of disk space, and uses under 2 MB of RAM while idling. 

Panda main window


During installation, all the checkboxes must be cleared before clicking Accept and Install in order to maintain unobtrusiveness.


Panda installation checkboxes


Popup ads seem to appear at a slightly higher rate than the other recommendations, but it happens rather infrequently.


Panda upgrade ad


User registration is not required to maintain free protection, but every time you run the program, a prompt will ask for your email address in order to create a free account.


Panda sign-in request

False Positives from Free Antivirus

Some users of free antivirus programs have reportedly experienced a higher number of false positives than from using paid antivirus programs.

If students aren’t entirely sure whether a suspicious file is safe to delete or not, a workaround that they can learn is to upload the file to VirusTotal (a subsidiary of Google), which then uses multiple antivirus engines to determine whether malware had truly been detected.

Internet Security Solutions

None of the recommended antivirus programs include an internet security program like the full-blown paid suites do. This is not a problem: files downloaded off the internet are still automatically scanned by the free antivirus programs.

What the paid internet security programs offer are things like a firewall and site rankings — things meant to prevent not just malware, but phishing attempts. In phishing, scammers try to obtain financial or other confidential information via spoofed emails or fraudulent websites that appear to be legitimate ones, with fields where sensitive information is entered by the victim.

Their methods work because they cast a wide net and only need a small percentage of “hooked” victims to prosper. They look for exploits in natural human behavior — such as the tendency of users to make typos when entering URLs (especially longer ones). Rings of phishers own thousands of domain names — all variants of URLs of legitimate, highly trafficked websites — sold and traded in darknet marketplaces across the world.

Avast Online Security is a Chrome extension highly effective at preventing such exploitations of natural human behavior.

Avast extension operating in a browser window


The extension not only adds reputation dots next to search results to lower the chances of learners being phished, it also automatically redirects them to legitimate sites if URLs are mistyped in the omnibar.

Avast Online Security can be downloaded from the Chrome Web Store. It is automatically added to Chrome if Avast Free Antivirus is installed.

Installing Software Is Just the Beginning

Installing an antivirus program and an internet security browser extension are like two steps on a flight of stairs. Achieving digital security zen requires climbing the entire flight.

By teaching fundamental security practices — from learning to create secure, unrepeated passwords, to keeping software updated — you greatly reduce the chances that students ever get phished or their computers get infected.

Share Your Thoughts, Gain Wisdom

Do you have any thoughts, ideas, or anecdotes involving your own learners? Share them by tweeting at us. Want to learn more about security best practices? Volunteer with us to gain wisdom while making a difference!

Free Antivirus — What’s Best for Slow PCs?

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Adam Lui