Weekend Project: Insulate hot-water pipes to cut down on heat loss

    Consumer Reports News: February 11, 2010 12:09 AM

    The pipes that snake out from a hot-water or steam boiler and from a water heater radiate heat much like a conventional radiator or baseboard. You might welcome that heat if you spend a lot of time in the same unheated space as your boiler or water heater.

    But if you'd rather decrease the heat loss from those pipes (not to mention prevent any burn risk from them), follow the four easy steps in this latest Weekend Project (photos for all four steps are below) adapted from our Complete Guide to Reducing Energy Costs ($19.45, including shipping).

    Insulated hot-water pipes can reduce heat loss and keep the water in them 2° to 4°F higher than uninsulated pipes, according to the U.S. Department of Energy. And your water heater will not have to flush and reheat the pipes each time you run hot water to the same area of your home during peak-usage periods. The only tools you need are a measuring tape, a pair of scissors, and a sharp retractable-blade utility knife.

    A very important point: Check your owner's manual or on the boiler or water heater itself for the required clearance from the appliance and its flue. Certain foams could emit toxic gases if they burn.

    Also find out which type of insulation and tape/wire/clamp to use. The installation here shows foam insulation, but for a gas-fired boiler or water heater, use unfaced fiberglass pipe wrap, held in place with either foil tape or wire.

    Finally, measure the diameter. Plumbing pipe is measured by its internal diameter (3/4 inch is common), but the actual outside diameter will be larger, depending on the material. The outside diameter of 3/4-inch black iron pipe is more than 1 inch, for example.

    1. Attach the first sleeve. Using the scissors, cut a 45-degree angle on one end of a length of insulation, then slip the sleeve over a section of pipe so that the angled miter cut ends up against the first turn in the pipe. At the other end, cut the sleeve to length with the utility knife.

    2. Add the second section. Cut a 45-degree angle in the sleeve and fit it against the 45-degree angle already in place.

    3. Continue cutting and fitting. Once you've made the first few turns, the run of pipe will likely be straight. Cover the pipes up to the point they go through the wall or ceiling and are no longer accessible. Every few feet you might want to secure the insulation to the pipe using acrylic tape, wire, or a cable tie.

    4. Seal the seams.
    Flexible-foam sleeves like the one shown often have adhesive on the edge of the slit so that you can seal them. Remove the protective strip on each side, then push the sides together.

    Insulate Water Pipes Weekend Project

    Essential information:
    Learn how to prevent frozen pipes at your home and use our advice to save on your utility bills. If you're in the market for a new boiler or water heater, find out whether that equipment is eligible in your state for a rebate as part of the $300 million cash for clunkers for appliances program.

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