A fun tale of how we spent a lot of money solving the wrong problem (because we hadn't yet engaged a home energy professional.)
Tags: home, ice, ice dams, led, lighting, More…performance
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A common misperception is that gutters cause ice dams, when the reality is that gutters are victims of ice dams.
Ice dams are caused by heat (or warm air) at the underside of the roof deck, melting of the snow on the roof, and refreezing of the meltwater as it runs down to a colder roof area (typically the overhang).
Ice dams are exacerbated by insufficient ceiling/roof insulation (particularly in slant ceilings), thermal bypasses or air leakage (such as unsealed interior soffits or kneewalls), heat sources in ceilings or attics (can lights, ducts, appliances), and architectural features such as valleys and dormers and chimneys (particularly when those all intersect in the same area, as with this house).
Ice dams are cured (or prevented at the design stage) by good ceiling insulation, good air sealing, elimination of ceiling penetrations and particularly of heat sources such as can lights, and good continuous bottom to top roof ventilation with soffit strip and ridge vents (with exterior air baffles to prevent infiltration of rain or snow). Avoiding valleys when designing a house or addition, or proximity of valleys and dormers, and chimneys in valleys is smart preventative design.
Thank you all for the nice comments. Back story is this was inspired by a certain high ranking state official in Maine who stood up in a roomful of home energy pros and said "home performance isn't rocket science." That, well, torqued me off.
Since we shot the video, we've completed a comprehensive air sealing and dense pack retrofit that reduced our air leakage by 35%. Early still, but for the three winter months before and after the job, our oil consumption went from 105 gallons per month to 59. Like so many, we've since learned how uncomfortable the upstairs of our house was before the work, which we rationalized for 15 years as a preference for sleeping in cool rooms.
This is just phase 2 for us on the path to deep, but we've made significant progress on all the issues in the video, and big progress on the ice dam challenges even in the huge snow year we had this year. But Peter Krych's comment is correct: it's a big valley that collects a lot of snow. So I remain a dutiful roof raker.
This time of year we're focused most on how to keep the house naturally cool, without air conditioning, minimizing electric load of fans, and not filling the place up to the gunnels with pollen. ;-)
The "gutter bypass" definitely makes my list of the top 25 hilariously misconceived solutions for 2011. And let me tell you: the competition is fierce!
I'm sure many of us lost the equivalent of a ski vacation because of a hasty investigation.Thanks for taking the time to share your story.
Thank you, your video was poetic, brilliantly edited and natrated: two thumbs up!
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