Quick fixes to "Webpage using significant energy" error

Remember the days when every time we’d open a new webpage in Safari it would launch a new window? Just a few of those and you’re completely lost! But since the adoption of tabs, everything became more organized, which in turn allowed us to keep dozens of them open at once.

If only we’d known the toll it would take on our machines. Some people today pay a lot extra for powerful rigs with the only goal to support their 100+ tab habit. You might be a bit of a tab hoarder yourself (no judgement, I am as well) if you’ve ever seen the “This webpage is using significant energy. Closing it may improve the responsiveness of your Mac.” message in Safari. But don’t run to the Apple Store for an upgrade yet — try these few ways outlined below first.

What to do when Safari is overloaded

The underlying reason for the “This webpage is using significant energy” error is your Mac’s resources being stretched too thin, which might either be the result of too many tabs open or even just a few tabs with websites that are continuously refreshing and loading up new scripts and content. 

So the first thing to do is simply decrease the number of tabs by closing some (use the ⌘ + W shortcut). Alternatively, you can try to reload Safari completely. To do that go to Safari in the menu bar and then select Quit Safari, or use the shortcut ⌘ + Q. If none of that had any result, proceed with a few more steps. 

Tip: The problem is often site-specific. So deciding which tabs close, start with online editors or streaming websites because they use lots of RAM.

1. Empty Safari’s cache and cookies

Like any other browser, Safari accumulates lots of information about the websites you visit and information you share. All this is recorded in your cache and cookies, which might become too power-taxing over time.

To clean your cache in Safari: 

  1. Go Safari ➙ Preferences in the menu bar (or use ⌘ + ,).
  2. Navigate to the Advanced tab and check the box “Show Develop menu in menu bar.”
  3. Now select the Develop menu in menu bar and click to Empty Caches.
  4. Restart Safari to make sure the cache is clear.

In addition, it could be beneficial to delete your cookies:

  1. Open Preferences once again.
  2. Go to the Privacy tab ➙ Manage Website Data…
  3. Click ⌘ + A to select all fields.
  4. Remove All.

Your Safari experience should become faster now, so the “This website is using significant energy.” error might be already gone. 

2. Turn off all Safari extensions

Another power-hogging aspect of any browser is its extensions. So disabling them might actually help the problem, especially if you have lots going at the same time.

To turn off Safari extensions:

  1. Fire up Preferences (⌘ + ,).
  2. Go to Extensions.
  3. Uncheck all boxes to disable your extensions. 
  4. Restart Safari to see if the error has disappeared.

Bonus: You can try turning extensions on one by one to see which of them really needs too much power.

3. Free up RAM for a faster system

Safari is showing you the “This website is using significant energy.” error because it has consumed all the available RAM. But other apps use RAM too. So freeing up that memory will give Safari more resources to utilize.

How do you free up RAM? Restarting your Mac is a quick but not a long-term solution. For immediate effect you need to use a special tool, like CleanMyMac X.

CleanMyMac X is a Swiss-knife utility designed to optimize all areas of your Mac. And resetting your RAM with it just takes a few clicks:

  1. Download a free version of CleanMyMac X.
  2. Open the app and navigate to the Maintenance tab, under Speed.
  3. Click Free Up RAM and then Run.

This app is notarized by Apple so you know it's a safe option to try in this case.

Now your Mac should feel a bit faster and all error messages should be gone.

Fix heavy memory consumers

It’s likely that the “significant energy” message is now gone. However, it’s good to make sure it doesn’t appear again by optimizing the apps that use a lot of memory and processing power.

CleanMyMac X will help you here as well:

  1. Get a free edition of the app.
  2. Open and go to the Optimization tab.
  3. Click on Heavy Consumers, check all the apps listed, and then Perform.

At last your Mac is fully optimized with a little help from CleanMyMac X🙂 In fact, if use this or similar Mac optimization app, you can skip all the manual steps of clearing your cache files and cookies, and turning off extensions and simply let the program to do the work for you in just a few seconds. 

Laptop with CleanMyMac
CleanMyMac X

Your Mac. As good as new.