Take off with APU ON or NOT? Embraer ERJ140

[M3thos]

Hello there to everyone,

I'm making a checklist for an Embraer ERJ140 (ovviusly I'm speaking about a virtual one), and I'm trying to keep it real as much as I can.

Now my question is simple, I'm aware that the companies in real world aim to save fuel, so I'm tempted to stop the APU bleed and APU straight after starting both of the engines.

Is this a real procedure followed by pilots of ERJ?
I'm asking this because in a tutorial video about an ERJ145 on yt made by a real pilot he's say to keep it till after the take off.... there are any advantages about this procedure? The APU gives you more "power" so a shorter take off? Is a must?

Thanks :)

[Kak Klaxon]

APU provides aircon for the cabin. You can use the engine bleeds instead but this robs the engines of a bit of thrust that you may need if you are runway limited, also APU air bleed has a bit more oomph so you can keep the cabin cooler in hot places.
So take off with the APU does not produce thrust it's self but not having to use the engine bleeds gives you more engine thrust......hope that makes sense.
I have not flown the 145 since 2004 but I think we took off with the APU on only on limiting runways (short).