.E3A File

File extension e3a is associated with the Carrier HAP (Hourly Analysis Program), an application that allows users to model HVAC (heating, ventilation, and air conditioning) systems for commercial buildings.

A typical .e3a file stores HVAC project.

How to open:

Use Carrier HAP to open and work with .e3a project files.

How to convert:

Conversion to other formats seems to be impossible, but projects are often exported to some exchange formats.