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Safari is the browser of choice for many Mac users thanks to its energy optimizations and deep integration with Apple services like iCloud. Occasionally, Safari will warn you that a website is using significant energy, but what does that mean and how do you resolve it?

What Safari’s “Significant Energy” Warning Really Means

This warning will appear at the top of a tab, right above the content of a web page. It doesn’t mean that the web page has crashed or has become unresponsive, but rather, that the web page is consuming more resources than you might be comfortable with if you’re running on battery power.

Example of the macOS Significant Energy Warning

Safari is telling you that keeping this web page active will deplete your battery faster, likely due to some element on the page like a script or embedded video. Advertisements can cause this problem as well since they often introduce a lot of overhead to a website.

RELATED: How to Show the Battery Percentage on Mac

You can see the effects of Safari by opening Activity Monitor (Search for it in Spotlight or find it under Applications > Activity Monitor.). Click on the “Energy” tab, and then click on the “Energy Impact” column to reorganize it in descending order to see the most energy-intensive processes at the top.

Energy Usage in Activity Monitor on macOS

At any time, you can also click on your battery icon in the top-right corner of the screen to see a list of apps that are using significant energy.

Things You Can Try

If you’re using the web page in question or you would like to keep it open regardless, there’s no harm in plugging your laptop into the mains and carrying on with whatever you were doing. This will counter the added power usage so that you can finish what you’re doing without losing battery power.

RELATED: How to Check Your MacBook's Battery Health

Sometimes, the warning is triggered by an error and reloading the page can fix the issue. Don’t be surprised if the warning comes back again, though, particularly in the case of web applications like Google Sheets or Spotify’s web playerRebooting your Mac can also help.

Restart your Mac and you may see an improvement in energy management.

If Safari is out of date, it’s possible that the warning was caused by an incompatibility with an element on the web page. Try installing any outstanding updates under System Preferences > Software Update and trying again.

There are a few other things that you can try to improve Safari stability, too. While these are unlikely to fix this particular error, disabling plugins can keep you safe, and removing unused extensions might speed up your browser.

Keep a Second Browser Handy

Safari is probably the best browser for the majority of Mac users. It’s well-optimized for energy usage, integrates with Apple services like iCloud, and generally performs well in terms of compatibility and responsiveness.

With that in mind, it’s always a good idea to have a second or even a third browser installed for those times that you run into issues. We’d recommend Chrome or Firefox, the two best-supported browsers on the web.

Profile Photo for Tim Brookes Tim Brookes
Tim Brookes is a technology writer with more than a decade of experience. He has covered a wide range of topics including Apple, security, productivity tips, gaming and more for publications like How-To Geek, Zapier, and MakeUseOf.
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