How to Insulate Pipes With Fiberglass Insulation

Wrapping pipes with fiberglass pipe insulation creates an energy-efficient barrier.

Insulating pipes with fiberglass pipe insulation lessens a water heater's work load, saving energy and money. Pipes with fiberglass insulation hold heat longer, deliver hot water faster and keep the water a degree or two higher than pipes without insulation. High-temperature pipes, like those that carry steam, can use fiberglass insulation -- foam insulation does not have a high enough temperature rating. Never expose fiberglass pipe insulation to weather; it must remain dry before, during and after installation.

Things You'll Need

• Serrated knife
• Tape measure
• Fiberglass pipe insulation tape
• Plastic squeegee

Instructions

1. Open the fiberglass pipe insulation. Fiberglass pipe insulation contains two fiberglass shells and a foil-backed paper covering. Gluing on the foil holds the two shells in place. One end of the paper covering extends past one of the fiberglass shells and forms a flap. The flap has a protective covering on it.

2. Peel the protective covering off the flap. Place the half of the pipe insulation without the flap on a straight section of pipe. Fold the half with the flap around the pipe. Press the center of the flap against the outside of the first half. Press the flap onto the insulation's paper covering, starting in the center and working to the ends of the insulation.

3. Insulate all straight sections of pipe. Butt the ends of each piece of insulation together. Stop the insulation between 1 and 2 feet from each bend in the pipe. Cut the fiberglass pipe insulation to length with a serrated knife.

4. Measure from the butt end of a piece of insulation to the outside edge of a bend in the pipe with a tape measure. Add the thickness of the shell to this measurement. Transfer the total to a piece of fiberglass pipe insulation and cut the insulation at a 45 degree with the serrated knife. Repeat this for the second side of the bend.

5. Install the cut pieces of fiberglass pipe insulation over the pipe bends. Adjust each piece to eliminate any gaps between the butt ends.

6. Cover each butt joint, including the butt joints on the pipe bends, with fiberglass pipe insulation tape. This type of tape has threads embedded in the covering.

7. Press the fiberglass pipe insulation's flaps and the tape against the pipe insulation with a plastic squeegee. Work the squeegee back and forth to remove all bubbles and folds in each joint.

References

• Johns Manville: Preformed Fiber Glass Pipe Insulation Specification
• Owens Corning: Fiberglas Pipe Insulation
• Leaning Pine Software: Insulating Your Hot Water Pipes Can Save Money and Protect the Environment

Resources

• Energy Savers: Insulate Hot Water Pipes for Energy Savings