Based on the phrasing "hot," I assume you are referring to "hotkeys" (keyboard shortcuts) or perhaps a situation where your computer is running "hot" (overheating) and you need a quick reset.

Mac (Safari): Use Option + Command (⌘) + E followed by refreshing. Troubleshooting: Fixing a Frozen Screen

Myth 3: F5 refreshes everything on the screen. Truth: F5 only refreshes the currently active window. If you have a browser open over your desktop, pressing F5 will refresh the webpage, not the desktop icons behind it.

Conclusion

If you want to look like a power user and save yourself seconds of time every day (which adds up!), here is the lowdown on how to refresh your computer screen using hotkeys.