Should I put my plants by the window?

Hi everyone well about 2 weeks ago my seeds sprouted and compared to everyone else mines are growing slower. I have a window in my house that constantly gets sunlight through out the day. Also maybe the reason my plants aren't growing fast enough is because of the air not being fresh? I have 2 27 watt 6500k cfl's, and 2 28 watt 6500k's. The plants are in beer cups so I doubt anyone would notice. I'm just thinking the fresh gases and more lumens that the sun puts out will give them a growth spurt. Help me out here.