Insulation strategy matters...

The level of insulation you should install depends on the area of your house. Your attic, walls, floors, basement, and crawlspace are the five main areas where you should consider adding insulation. Use the Home Energy Saver tool for recommendations based on the specifications of your home, or find general regional recommendations on the Department of Energy’s webpage on insulation.

https://www.energysage.com/energy-efficiency/101/ways-to-save-energy/