I.E.S. offers a completely free version of a simple energy analysis called VE-Ware. My favorite feature of this program is its compatibility with Revit. It installs a plugin directly inside of Revit and with a few click you can make a simple energy usage and carbon emission analysis. For participating schools the entire tool kit is free. For students in non-participating schools they have a student offer (linked below).
With the free VE-Ware you will be able to:
1. Import geometry data2. Tell it where your building is in the world
3. Define your: building type, construction materials, heating and cooling system types and room types
4. Press a button – automatic detailed thermal simulation is performed for you
5. Get output on: energy consumption, CO2 emissions and US benchmark against the Architecture 2030 Challenge
6. You can then easily modify your building and assess different options.
As far as ease of use and coherence go this program is very simple.
Here is a list of links: