Hot water loses 2-4 degrees of its heat when left in uninsulated lines. Insulating hot and cold water lines can save energy, reduce condensation problems and decrease the chance of frozen pipes.
Step 1: Refer to the owner’s manual before installing insulation near any appliance. Foam insulation can emit toxic gases when exposed to excessive heat. Keep insulation at least six inches from the flue of any appliance and 3 feet from any heat source.
Step 2: The three most common types of pipe insulation are foam sleeve insulation, foil-backed fiberglass insulation and fiberglass insulation without backing. Choose one type, or use a combination of types to simplify the job. Foam sleeves install easily on straight runs of pipe. Fiberglass insulation works well on joints and turns and must be used when insulating over heat tapes or on steam lines.
Step 3: Make sure the pipes are clean and dry. Use a wire brush to knock off any rust or residue and wipe away any condensation before installing insulation. If there are leaks in the waterlines, now is the time to fix them.
Step 4: Start by installing foam sleeve insulation on the long runs of pipe. If the sleeves have preglued openings, pull the plastic backer off to expose the adhesive after the sleeve has been positioned properly. Seal any open seams with high-quality duct tape. Position the opening slit on the underside of horizontal pipes and on the inward facing side of any vertical pipes. Secure open ends by wrapping with duct tape or installing a plastic zip tie one inch from each end. Wrapping insulation tightly anywhere else along the sleeve will reduce its effectiveness.
Step 5: Use scissors or a serrated knife to cut sleeves of foam insulation at 45 degree angles to fit snuggly over elbowed sections of pipe. Wrap these mitered corners loosely with duct tape to secure them.
Step 6: Wrap tees and other jointed portions of pipe with fiberglass insulation. Overlap the insulation to improve its effectiveness. Secure in place with duct tape and wrap exposed fiberglass with plastic.
Step 7: For improved efficiency, install fiberglass insulation over foam sleeve insulation. Wrap pipes loosely in a spiral fashion, overlapping each loop of insulation by half its width. Secure the ends with duct tape and wrap exposed insulation with plastic to protect it from condensation damage.