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February 2014 EnergyWiseSM Tip:

February 2014 EnergyWiseSM Tip: Icicles

Icicles put the finishing touch on many of Thomas Kinkade’s paintings of nostalgic-looking homes locked in time and surrounded by a winter wonderland. Perhaps you have quietly passed the time watching an icicle form, becoming longer and longer with each drop that trickles downward. Or maybe as a child, you energetically jumped to pull icicles off the sides of your home to use as a toy sword. Icicles may seem beautiful, magical or picturesque, but they can also signal big troubles for you and your home.

Icicles are the result of “ice dams,” which are a buildup of ice on the roof along the overhang or eave. Eaves are the parts of the roof that extend beyond the exterior wall and gutters attach to. Ice dams form when the upper part of the roof is warm enough to melt snow but the eaves and gutters are cold enough to freeze the runoff into icicles. As the ice gets thicker and thicker, it stops water as it comes down the roof, making an ice dam. Eventually, water coming down the roof is backed up enough that it does not refreeze because it continues to be warmed by the house and its attic. Finally, as the water gets deep enough behind the ice dam, it is pushed up under the shingles and into the house causing water damage.

The best way to prevent this from happening is to keep your attic cold in the first place. The majority of heat in the attic comes from heat inside the house leaking into the attic. If your house has big, beautiful icicles, you are probably using way more energy than you need to keep your home warm. So what can you do?

Attic insulation and air sealing This is the primary way of stopping ice dams. Since most of the heat comes from the below the attic, ensure the attic is properly insulated and air sealed. In Nebraska, your attic should have enough insulation to equate to an R38 value. If you are not sure, contact your local hardware store or utility company to learn more. If more insulation is needed, you may qualify for an EnergyWiseSM energy efficiency incentive from your local electric utility to help offset the cost of the additional insulation.

Air leaks transmit a lot of heat into the attic quickly, so they are important to stop as well. Pay particular attention to sealing up and insulating the following major sources of heat in the attic:
  • Chimneys
  • Plumbing stacks
  • Recessed lighting from the ceiling below
  • Bathroom and clothes dryer ventilation
Bathroom and clothes dryer exhausts can be the worst of the four. Not only are they bringing heat into the attic area, some are vented right into the attic. This will bring additional moisture into the cooler area and can lead to problems like rotted roofs and rafters, ruined insulation, moisture inside the walls, mold, and peeling paint.

More attic ventilation Though secondary to insulation, ventilation is also important. No matter how much insulation is in your attic, some heat will still come through. Insulation and sealing only slows down heat transfer. The purpose of attic ventilation is to give that heat somewhere to go. Note that most homes built before 1980 have lousy ventilation. Again, if you are not sure, visit with your utility company, local hardware store, or home contractors in the area.