NRG Insulate Hot Water Pipes

How to Insulate Hot Water Pipes

Project difficulty: Medium

Estimated energy savings: 3%-4% per year on water heating bill (about $8-$12)1

Time to complete: 2-3 hours depending on house size

Materials needed: Tape measure; pipe sleeves or fiberglass insulation from the hardware store; gloves and long sleeves/pants; scissors, box cutter or utility knife; tape, wire or cable ties

Next to heating and cooling your home, water heating is usually a homeowner’s second largest energy expense.2 If your hot water pipes are not insulated, then they aren’t working as efficiently as they could be, which forces your water heater to work harder and your energy bill to surge. 

Some home efficiency consultants will tell you to hire someone (i.e., the consultant) to insulate your pipes, but in most homes, it's actually quite a simple job. Consider following the steps below to insulate your hot water pipes yourself. It only takes a few hours at most, and you’ll notice the change almost immediately. When you turn on the shower or faucet, you won’t have to wait as long for the water to heat up. Your electricity bill may decrease by only a few dollars per year, but those few dollars add up over time. Plus, you will not need to leave the water running as long for it to heat up, so you could save on your water bill, too. Those benefits, combined with quicker access to hot water make this little fix worth it. 

You can also lower your energy costs by being aware of how much hot water you use, and attempt to use less. We recommend simple undertakings such as: fixing leaky faucets, installing low-flow fixtures and using energy–efficient appliances throughout your home.

You can find instructions for this project many places, but the recommendations from the U.S. Department of Energy, simplified and explained below, are the easiest and most safety-conscious we found.

  1. Ensure the pipes have no leaks and that they are completely dry before you begin. 
  2. Measure the length of the pipes starting at the water heater to determine the amount of insulation needed. Be sure to measure all accessible hot water pipes, particularly the first 3 feet from the water heater.
    Note: On gas water heaters, you should not place any kind of insulation within 6 inches of the flue. For safety, if the pipe is 6-8 inches from the flue, you should use fiberglass pipe-wrap (at least 1-inch thick) without a facing. Otherwise, use regular pipe sleeves.3
  3. Cut the pipe sleeve or insulation to the necessary lengths. 
  4. Place the pipe sleeve onto the pipe with the seam face down on the pipe. 
  5. Secure the pipe sleeve by wrapping tape, wire or cable tie around it every two feet or so.

Sources: U.S. Department of Energy
1The U.S. Department of Energy estimates you can save 3%-5% per year on costs associated with heating your water, but your results may differ depending on the unique characteristics of your home. https://energy.gov/energysaver/articles/how-much-can-you-really-save-energy-efficient-improvements
2U.S. Department of Energy https://energy.gov/energysaver/reduce-hot-water-use-energy-savings
3U.S. Department of Energy https://energy.gov/energysaver/projects/savings-project-insulate-hot-water-pipes-energy-savings

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