How can I make my interior scene better lighted? I am using 2 sun lamps, the principal one has the strength set to 30.000, the other one is pointing in the opposite direction, is bigger, and has the strength at 1200. An HDRI is supposed to light up the scene a little bit more, but even with all of this, I haven´t achieved a nice lighting, I am using filmic color management with the exposure at 2100 in order to see what it is in shadow areas (sofa), but I end up having a lot of noise, even with 2000 samples.

My glass is made by a glass and a transparent shader, mixed by an 0.855 factor. I don´t think the problem is the glass, becouse i made a test, deleting it just to see what the light would do without it, and the result was the same.
As I said, there are techniques at your disposal to reduce noise (and by extension, render time) that don't involve relinquishing your shadows.  Here's an example showing how much Clamping actually affects shadow exposure.  I've used the Denoising filter (for simplicity) included with Blender 2.79 Candidate but there are more effective and more flexible ways of controlling noise as well.

Denoising settings for this render:



Notice also the wood texture outside the window, with an Indirect Clamping value as extreme as 1.00, it's affected as well, since it's technically not Direct light.





Full size (Click to enlarge):