Electrons transfer their energy to metals much more easily than through other substances. You spend a lot more energy heating and cooling your home when you use noninsulated metal ducts, bleeding out tons of thermal energy, which makes your electric bill an unpleasant sight. Besides sealing your ducts, you can also get them insulated to increase your energy savings.
If you want a simple type of insulation that doesn't cost much to install and doesn't require replacing your current ducts, you may try blanket-type insulation, also known as "batt and roll." This type of insulation comes in rolls that wrap around a given space in segments. If you have a segment of duct to insulate smaller than the width of one segment of your insulation, cut the insulation to trim it down to the desired measurement. It packs a large amount of fiberglass or other material into a sheet coated with metal foil or some other type of material.
Flexible ducting works for you if you have enough money to throw into a duct changing project. Installing this kind of duct reduces the amount of hassle required to get into tight spots in your house. You don't need to work with complicated pathways since the ducts bend anywhere you want them to. The Arizona Public Service Company recommends that you get R-6 flexible ducts for the best protection and productivity.
If you're looking for something easy to install that doesn't require protective gear, you may find reflective insulation attractive. Reflective insulation proves a good option for the average handyman who wants an effective barrier against thermal energy loss. It also protects your ducts from thermal loss just about as much as blanket duct wrap does, but it doesn't have any fiberglass or other materials that make your hands itchy after you finish handling it.