250hps v 4' T5 high output.......Flowering

Hello, I have a question about lighting choice for anyone with experience of using T5 for flowering.
This is my first grow, 5 white widows. I've got a small space 5' wide 1.5 deep and 7' high
Veg'd my babies under a 2' T5 the blurb says it emits 10000 lumens, they have really thrived under this,
I'll be be buying a new light very soon for flowering and I've seen this bigger T5 it's this: FOUR (4) T5 High Output (F54T5HO) BLOOM SPECTRUM 3000K Fluorescent Bulbs. Would this better than the 250hps i was planning to buy. The blurb says this emits 20000 Lumens. I'm no expert, but this seems around what a 250hps pushes out, but with less heat.
I have a few issues with my growroom, like not being able to vent it properly, except have the cupboard door open with the ceiling fan going and that its not very deep, so i have to have the plants in a row, thus, having a four foot light would cover them all.
Basically, would my yield be affected by going with the T5?
Because this light seems ideal for a room with heat and space issues.
Please, anyones input on this decision i need to make would be gladly accepted.
Thank you indeed.