There are times when you will want to have an icon in place of "home" in your main Joomla menu. You just want some beautyful display of an icon instead of usine the text: "home"

This tutorial will show you how to achieve this.

Go to Menus > Main Menu > Home.
Click to edit the Home link and you'll see a screen like this:come up.

Click the "Link Type" tab.
Set "Add Menu Title" to "No". This will hide the text from showing in the menu.
Click "Select" next to "Link Image".

Either choose the icon you want to use, or upload a new one.

Click "Insert" to add the icon chosen.

Save the menu link.
Check the front of your site and the icon will be visible.

You may need to adjust the icon to the right size.

Source: https://www.todhost.com/knowledgebase/714/How-to-add-a-home-icon-to-the-Joomla-menu.html