How to get rid of fireflies coming from apartment windows? I've tried different settings of clamping, sun/no sun, lamps, emission, higher samples, etc... but I can't seem to get rid of them. Not keen on blur nodes or similar since I need to see the inside of the apartments > people, furniture, etc... 
And I also need reflections from the windows so I don't want a hole instead of windows.

Download Blend file here: http://we.tl/2oPC7y4zdc

And please don't mark this as a duplicate cus I've tried finding answers here on blender.exchange, Blender Guru and YT without any luck as you can see.

Note: I'm a total noob. Just started Blender about a month ago.

See ref img >
I'm not sure that what you describe are fireflies but noise and pixelation resulting from rendering at a low resolution with low samples.

This is a render form your original file
just 100 samples at 50% resolution.
:

EDIT

Changing the glass of the windows to a node tree like this you can have transparency and reflections (look at the added emitter plane on the left).

Rendering with more samples at a higher resolution will give you a cleaner image.





For a deeper explanation on the nodes used please read this answer

Note the change with more samples and a higher resolution:



(click on the image to enlarge)