How to Insulate Water Supply Pipes – Forbes Advisor

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  • Working time: 2 to 3 hours
  • Total time: 2 to 3 hours
  • Skill level: Beginner
  • Project costs: $ 100 to $ 200

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Insulating your water supply lines saves energy, money and water. It’s such a simple project that you might wonder why you didn’t do it sooner.

It is estimated that insulating your water supply pipes will reduce heat loss by two to four degrees Celsius. Plus, you save water by not having to wait so long for hot water to come to the tap.

If your water supply lines are accessible, you can isolate them all in a matter of hours.

Water supply pipes to be insulated

Not all water pipes need to be insulated. Hot water pipes leading out of the water heater must be insulated. When you have full access to all of your water pipes, try to insulate the entire route from the water heater to the distribution points such as sinks, kitchen sinks, showers and bathtubs.

Water pipes leading to the water heater do not need to be insulated. Cold water pipes that lead to different parts of the house also do not have to be insulated.

Type of pipe insulation to buy

Fiberglass pipe insulation

Fiberglass pipe insulation comes in long strips of fiberglass, similar to the type used in walls and attics. The insulation is covered on one side with a foil lamination and is wrapped around the pipes like a tape.

Fiberglass pipe insulation should be used in areas of high heat, such as near the water heater or stove. It can also be used in areas where the pipe makes a lot of intricate turns, as the fiberglass pipe insulation can easily be wrapped around bends.

Foam pipe insulation

Foam pipe insulation comes in two meter long pipes that are split lengthways so that they can be installed over pipes. Plastic strips cover the glue on the gap, and these strips are removed to glue the two sides together.

Foam pipe insulation is valuable with long water supply pipes. The foam material quickly fits lengthways over the tubes.

Foam insulation can rotate, but it’s a more complicated process than fiberglass pipe insulation. You need to cut two pieces of pipe insulation at a 45-degree angle and join them together. Or, you can buy separate foam elbows and tees that also make the curves, but without the bevel cuts.

When to insulate water supply pipes

Since insulating your water supply pipes is an indoor activity, it can be done at any time of the year. Ideally, you should insulate the pipes before the cold season sets in in your area.

Security aspects

Don’t remove asbestos pipe insulation, a white cloth-like wrapping often found in older homes for pipes and ducts.

Inhaling asbestos can cause asbestosis, an aggressive disease that scars the lungs. Worse, inhaling asbestos can cause mesothelioma, a type of cancer that is almost always fatal.


  • Utility knife
  • Universal knife blades
  • scissors
  • square
  • Tape measure
  • flashlight
  • ladder
  • Respiratory protection
  • Eye protection
  • gloves


  • Foam pipe insulation
  • Elbows and T-pieces made of foam (optional)
  • Isolation with fiberglass tape
  • Foil tape
  • cable ties


1. Insulate near the water heater

Wrap fiberglass pipe insulation around the hot water supply pipe coming out of the water heater. Extend it about 10 inches. Wrap it with foil tape.

2. Bend the insulation around the curves

To get the foam pipe insulation around 90 degree bends, use the square and utility knife to cut a piece of insulation at 45 degrees. Next, cut a separate piece of foam insulation at 45 degrees. Attach the two pieces of insulation to adjacent pipes and slide them together so the angled ends meet.

3. Peel off the adhesive tape

Remove the foam insulation on the pipe after you have measured it and attached it dry. Peel off the two adhesive strips on the split section of pipe insulation.

4. Glue foam insulation to the pipes

While holding the two adhesive sides apart with your fingers, carefully place the pipe insulation on top of the pipe. Then press the adhesive sections together firmly.

5. Safe isolation

Secure the foam insulation to the pipes by either tying them with zip ties or by wrapping foil tape around every foot up to 18 inches.

6. Continuation of isolation on long runs

Use the ladder to climb pipes that are high in the joist area. Continue the foam insulation on long water supply pipes that lead to various water distribution points throughout the house, especially the kitchen and bathroom.

7. End at distribution points

Continue to wrap insulation around the pipes until you reach the point where the water pipes open into the soil above. There is no need to wrap water supplies under sink cabinets.

When to call a professional

Insulating water supply pipes is so simple and easy that it is rarely a job that requires additional help. However, if you don’t have access to remote sections of pipe, you may want to hire a contractor, plumber, or repair service to do the work.

If you need to remove drywall to gain access to the pipes, it is also a job for a contractor or drywall company. If you encounter asbestos pipe insulation that needs to be removed, call an asbestos removal company to do the job.

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Frequently asked questions (FAQs)

Should you open walls to insulate pipes?

In general, water supply pipes inside walls are considered to be sufficiently insulated that they do not need additional insulation.

An exception is when the pipes are touching or close to the outer jacket and freezing temperatures are regular in your area. These pipes should be insulated so that they do not burst when they freeze.

Does asbestos pipe jacketing have to be reinsulated?

When asbestos pipe jacketing is in good condition, it is an effective type of pipe insulation and does not need to be removed and replaced. Asbestos is safe as long as it is untouched, undamaged and undisturbed.

Should you ever insulate cold water pipes?

Usually you only insulate hot water pipes. However, if you have cold water pipes that are unusually exposed to the elements, such as

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