I have a 1960 ranch home with full brick exterior. My exterior walls are 2x4 framed and 1" plaster on the inside. There appears to be a very thin blanket of some old type of insulation in the walls (about 1.5 inches thick and takes up less than half the stud cavity).

I have a friend that has offered to dense pack these exterior walls with cellulose. He has an industrial blower and says he has done this many times for his investment properties. He uses a tube and gets the cellulose all the way up and down the cavity.

He plans to drill a hole into each stud cavity from the basement. The way the house is constructed there are deep sill boxes and as a result there is ample room to drill up through the wall bottom plate and into the stud cavity.

My concern is:

Is insulating the walls necessary? Doesn't the brick do a pretty good job of stopping the air flow and keeping out the cold?

Will this cellulose grab moisture that comes through my brick? Or is this an acceptable method as long as there is an air gap between the brick and some type of sheathing covering the exterior wall framing?

Do everything else possible first, and save the walls for last. Insulate the attic/roof to the fullest extent possible (within limits, because the rate of return on investment declines as the insulation thickness increases much beyond R-38 or so), weatherstrip, caulk or seal everything you can find. replace any now substandard windows or add storm windows, add storm doors.

Then after all that, do the walls, if ever, and if you do, don't expect any miracles in your energy bills.

Found a lot of good videos and posts about this at www.startinsulating.com