Hi. I have a 10 years old 2 story home in Pittsburgh. My question is when I checked attic insulation and found 6-7 inches evenly spread blown-in insulation. But I heard from someone in my neighbor told me this should be enough insulation. I searched and studied found at least 19 inches of insulation on attic which should be R-49 is required. I checked temperature 1st and 2nd floor had 3-4 degree different. Do I need a more insulation or this should be enough. Thanks in advance.