If your attic looks like this...
You NEED more insulation! A great rule of thumb is... if you see wood it is no good! It is best to cover those joists with at least 6 inches or more of BLOWN IN insulation. Try to avoid cross batting, due to gaps and thermal deficiencies.
NOT ENOUGH insulation in this photo!!!
Air seal it, and then bury that wood! If you see wood it is no good! Throw R-49 at minimum in that attic!!
See that ruler poking up in the photo?
You should have one of those every 300 - 400 square foot of attic space. This way the inspectors know you have an even blown in insulation job! This is code as well!
This homeowner did it right!
We installed at least 12 inches over the joists! No wood is good!!! This home will be comfy and cozy all year round!