how to size a window header
 

how to size a window header?
i want to add a window to our basement. the header must support the main floor above plus the roof. i live in the pacific northwest so we experience snow loads. is a double 2x8 enough for an opening approx. 48" wide?
the answer to your question is dependent upon several other pieces of info you have not supplied: 1) what is the tributary area of the floor and roof load that this header will be supporting? 2) what type of wood will you be using for the header?