Overall cost a few dollars for some screws- the rest made from junk around my shed.
Length- 1130, Width- 620, Height- 570. Height from floor- 1330.
Mesh top for ventilation. Commercial dimmer for heat control. Plastic viewing window.
I was going to comment on the height of the bulb and how you can't lower or raise it, then I saw the dimmer switch. Good job! Only think I would have done different is attached the bottom with a hinge/latch system for easy cleaning. Right now I'm using a rubbermade tub so you have me beat by a mile!
I had something very similar with my first batch of chicks. The only thing I am doing differently with the next batch is to make sure they can't jump out of the brooder when you open the door. So I would make the ledge you have now higher to prevent curious chicks from jumping out. I think I will make mine at lease 30 cm high at the door, and removable so that i can clean things out easily.
I also made the whole front into two doors that open, again for cleaning ease. My top was screen too, that worked well. Now it's a brooder/coop so it has a fixed roof, hence the cleaning issue.