Insulation (Seal & Insulate)

Can I add new insulation on top of old insulation?
How do I know if I have enough insulation in my attic?
Can I over-seal my house or make it too tight?
Do I need a contractor to seal air leaks and insulate my home?
What safety steps do I need to take before sealing and insulating my attic?
Where are the big air leaks in my basement?
Where are the biggest air leaks in my home?
How much insulation should I add to my attic?
Where are the big air leaks in my attic?
What is "Seal and Insulate with ENERGY STAR?"
Why is the room over my garage colder than other rooms in the house?
Are there ENERGY STAR certified radiant barriers?
Should I install an insulating blanket on my water heater?
How should I insulate my crawl space?
What is the Rule Your Attic Campaign and where can I find information on it?
Can a radiant barrier be painted on?