Jacquie writes from Sicklerville, New Jersey: "I have a 32-year-old end unit townhouse. All outside walls are cold in winter and warm in summer. We're in bad need of re-insulation & are considering blown-in insulation. How does that work on existing walls?"

Answer: Blown-in or loosefill insulation will work in existing walls but it must be installed carefully to avoid damaging the walls. It is also important to make sure the wall cavity is filled completely and does not contain voids where there is no insulation. For these reasons we don't recommend insulating existing walls with blown-in insulation as a do-it-yourself project. Contact an insulation professional in your area and ask for an assessment of the situation.