About this Project

When contractors compute heating and cooling loads, they tack on 10 or 20 percent for losses from the ductwork or pipes. If you insulate those that run through an attic, garage, or other unheated area, you can prevent most of this loss.

Heat also escapes from bare hot-water pipes, meaning water sitting in pipes cools down between uses; then you have to run extra water to get hot water out of a faucet. Wrapping these pipes will reap big dividends. Wrapping cold water lines won't save you energy dollars, but doing so will eliminate dripping and sweating from condensation, thus avoiding water spots or damage.

What about ducts that run through an unfinished or partially finished basement? Here you have a choice. If you're using the space as a living, play, or shop area even though it isn't finished, chances are you're depending on radiated heat from the ducts to keep things somewhat warm down there. In this situation, you would be better off to insulate the walls and forget about the ducts.

If your basement gets only occasional use, consider installing a couple of new basement registers and insulating both the ducts and the floor above.

Duct insulation comes in 1- and 2-inch thicknesses. Get the thicker material, especially if your ducts are rectangular; 2-inch wrap cuts losses by about one-third more than 1-inch material. You'll also need several rolls of duct tape to seal all duct joints before you insulate.

If your ducts don't have dampers to balance airflow, add some before you insulate. Insulation ups the temperature of air at registers, and you'll want to do some fine-tuning afterward.