January 2020 EnergyWiseSM Tip: Icicles
By: Energy Efficiency Program Manager Cory Fuehrer
Can you think back to your childhood and remember the "magic" of icicles? While growing up in a century-old farm house, I remember wintry "No School" days when my mom would bundle me up in so many layers of sweatshirts, coats and overalls that I could barely move. Then, I'd waddle outside and start my polar expedition around the farm to discover the winter wonderland and search for the perfect icicle.
Inevitably, I would find the most beautiful ones hanging from the gutters on the south side of the house. Over the next couple of hours, I would keep checking to see how much they had grown. Then, before they became too long, I would break them off and carefully put them in the deep freezer thinking how refreshing they would taste in July when it's 95°F. Sadly, I never experienced that summertime sensation because mom always threw them out when she defrosted the freezer during spring cleaning.
Unfortunately, not all stories involving icicles are as innocent or benign. It seems every winter, we hear a news of someone injured by falling icicles. More likely, we hear very little about the gutters pulled off homes when the icicles become too heavy or the ice that builds up on the roof behind them, melts and rots wood in attics. Their beauty disguises the warning of other potential damage including loosened or broken shingles, cracked chimney stacks, ruined insulation, damaged drywall or even a roof collapsing.
Icicles form on days when the outdoor air temperature is subfreezing but heat escaping through the attic melts snow or ice on top. As it drips off the roof, a water droplet freezes as it loses heat to the cold air. Over time, ice gets thicker and thicker to create an ice dam. Eventually, the water behind the ice dam builds up enough to push under the shingles and into the house.
Roof rakes, heat cables and ice dam removal companies only address the symptoms of ice damming. While you may never completely eliminate icicles, there are two parts to a long-term solution: reducing the heat escaping into the attic and removing the heat that does.
Attic insulation and air sealing
Since most of this misplaced heat comes from below the attic, ensure proper insulation and air sealing. According to the Department of Energy, Nebraska homes should have enough insulation to equate to at least an R49 value in attics. This value is equal to about 15 inches of fiberglass batt material assuming an average of R3.25 per inch of thickness. Note that if you have loose-fill insulation in your attic, the R-value of does not change proportionately with thickness. Rather, manufacturers provide coverage charts that specify the amount needed to achieve a particular R-value.
Air leaks transmit a lot of heat into the attic quickly. When trying to seal up sources of these leaks, pay particular attention to the following items that often penetrate into the attic:
• Plumbing stacks
• Recessed lighting from the ceiling below
• Bathroom and clothes dryer ventilation
Of the four, bathroom and clothes dryer exhausts can be the worst. Not only do they bring heat into the attic area, some are not completely ducted outside and dump warm, moisture-laden air right into the attic. This often leads to problems similar to ice damming such as rotting rafters, ruined insulation, moisture inside walls, mold, and peeling paint.
More attic ventilation
Though secondary to insulation and sealing, ventilation is also important. No matter how much you insulate, some heat will still come through. Proper attic ventilation promptly moves the undesired heat outdoors before it causes melting on your roof.
Many homes built before 1980 have inadequate attic ventilation. When checking your attic's insulation levels, look for these signs of moisture problems:
• Damp insulation
• Unnaturally dark or discolored decking
• Dark streaks on roof boards around nails
• Orange resin beads on rafters signaling sweating wood
• Moisture on roof boards and rafters
• Crumbling, curled roof shingles
Southwest Public Power District, in partnership with Nebraska Public Power District, are happy to help you make the most of the energy needed to keep you warm, safe and sound this winter. For additional ideas, as well as information on EnergyWiseSM incentives to help with the cost of efficiency improvements, contact Southwest Public Power District or visit www.nppd.com.