Are you planning to blow in more fiberglass or cellulose? A friend of mine owns an insulating business and he recommends cellulose due to it forming sort of a crust on top over time that helps stop heat flow. They will even put it on top of existing blown in fiberglass to get the crust on top.
And it will settle, when I built my house 5 years ago I blew in around 20 inches of cellulose in my attic. I was told you can usually figure on around 6 inches of settling. With that and the closed cell foam on my walls, I can practically heat my 2000 sqft slab home with a candle. I have all propane appliances and keep my house at 70 in the winter, a 500 gallon tank of propane lasts me 2 years.
And it will settle, when I built my house 5 years ago I blew in around 20 inches of cellulose in my attic. I was told you can usually figure on around 6 inches of settling. With that and the closed cell foam on my walls, I can practically heat my 2000 sqft slab home with a candle. I have all propane appliances and keep my house at 70 in the winter, a 500 gallon tank of propane lasts me 2 years.