Well unless it is really cold outside you dont need a heated box.
I live in the UK and I do use a homemade heated box during the really cold periods.
Here is a photo of my heating setup on my old rocker table.
Note the fan and thermostatic power switch which is inside the box when it is on.
I also have a double glassed window in the fron of the box which is not shown. this is usefull to see what is happening inside the box.