One of the most important features of your chimney is the chimney cap, also known as the chimney crown. Some older chimneys do not have a chimney cap in place, and if yours is one of these chimneys, you need to seek installation ASAP. A chimney cap is a simple installation, often a metal crown that sits atop your chimney, but still leaves enough space to vent (usually in the form of a mesh opening). Here’s what makes a chimney cap such a vital installation throughout the year.