I just bought a house and i have no idea if there is already insulation in the walls.I would rather find out now...while it's warm...rather than when i get my energy bill in Jan.I know that we have to replace the insulation in the attic already.Everyone tells me blowing it up there is better then the blankets.Also, it looks as though the cellulose insulation is best for walls...if i have to do that.Is this something you can DIY and if so,what is the best way to go about it?