Question about lights

Hello,
I am new and there are still a lot of things I don't know. My question is about lights for a 20 tall terrarium. How well would a 'grow light' work? I think they are T8s.. Also, how much heat would something like this produce?

My other question is, if your light is goin through a glass top does it decrease its effectiveness? I plan of having quite a few plants.

Thanks!
Levi