An insulation rating of R-8 is recommended for cold climates. Duct insulation will pay for itself in energy savings in about two and a half years, and continue to save energy and money in years to come. If you don't feel comfortable insulating ducts by yourself, don't hesitate to call a professional to do it for you. Even with the installation cost, the energy savings will be well worth your investment in the long run. In addition to protecting your ducts, it's also important to protect other heat sources like radiators.
Radiators can also lose a great deal of heat to the walls they are installed against.
To prevent heat loss, install a foil-covered reflector between the wall and radiator. You can make the reflector from foil-covered cardboard. It is available at most building supply stores. You can improve the airflow of your heating system and reduce the amount of energy needed to keep heat flowing evenly throughout your home by removing common air circulation barriers, such as furniture and rugs that may sit on top of your heat registers. To maintain your heating registers, make sure they are clean and free of foreign objects.