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Changing the mindset of people

Peter L | Posted in Energy Efficiency and Durability on

Got into a debate regarding building an “airtight” home. The other party claimed that a “leaky” wall and window home is better as a home needs to “breathe”. I argued that a properly sealed home is better and controlling air exchanges via an ERV or HRV is best practice. He argued from the old school mentality that walls and windows need to breathe and paying for an ERV/HRV is dumb when you can get “free” air exchange via the leaking wall and window assembly.

When will this tired and false narrative of leaky homes be finally put to rest?

Building Science proves that air tight homes with proper air ventilation via ERV/HRV is best for energy and home comfort.

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Replies

  1. Expert Member
    Dana Dorsett | | #1

    >"When will this tired and false narrative of leaky homes be finally put to rest?"

    Most people making those arguments don't understand the difference between vapor tightness and air tightness either, and where/why either would matter. Opening a window for fresh air can be valid, and more reliable than random air leaks.

    There's a wealth of ignorance out there- plenty to go around, and not just in the building industry. But the problem will never be put to rest until the building industry (if not the public at large) get better educated on these topics.

  2. Joel Cheely | | #2

    Energy is too cheap right now, so people don't feel it in the pocketbook. Why do you think everyone (including me, now that I think of it) drives around in an empty pickup truck? Besides, we're living in the age of deniability and skepticism. Many of the people who make the decisions about how to build a house think Building Science is a waste of time and money.

    1. Expert Member
      Dana Dorsett | | #3

      >"Why do you think everyone (including me, now that I think of it) drives around in an empty pickup truck?"

      Hey, driving an empty pickup is greener than driving a pickup full of extra stuff that never gets unloaded... ;-)

      Me, I'm driving around in an empty used Prius (practically new at ~95K miles) that set me back about as much as a new set of tires for my brother's truck.

      The empty Prius that I used to drive around in recently took an early retirement (due to structural rust) after only ~250K miles, but was still beating it's EPA fuel economy ratings by a good margin.

      But maybe it's just 'cuz I'm cheap (go ahead and ask mi esposa! :-) )

    2. Expert Member
      Zephyr7 | | #9

      I’m not so sure energy is so cheap. I’m also always in favor of maximizing efficiency as a “good thing” whenever possible. It’s certainly possible to go overboard, but some things make good sense (air sealing especially). I don’t know why anyone would be against doing basic air sealing during construction when it’s easy during construction — it’s not very expensive, and has very real energy efficiency advantages. Doing the same work later as a retrofit is FAR more work.

      Bill

      1. Expert Member
        Malcolm Taylor | | #10

        Hopefully it also to some degree future-proofs a house. Most of the really big changes around energy sources and prices I've experienced in my lifetime were largely unanticipated.

      2. John Clark | | #14

        IMO a tight house requires that the HVAC system is designed/sized correctly along with the mechanical ventilation. The margin of error becomes much smaller in this regard.

  3. Peter L | | #4

    In addition, they believe in burning log woods in a stove as a primary heat source for a 4,000 sq.ft home :( Backup heat sources would be propane and hydronic oil.

    Wood heat source burning pollution is bad in Alaska during winter. Air quality suffers greatly from burning wood logs all winter long in thousands of homes.

    1. Expert Member
      Dana Dorsett | | #5

      If it's sustainably harvested wood source burned at better than 50% net thermal efficiency burning wood isn't terrible from an atmospheric carbon point of view. But if it's an outdoor wood boiler the system efficiency might be barely better than 50%, even if the boiler is 75-80%, and the local air pollution is pretty bad.

      But at least in AK you don't have any neighbor to complain about it- nobody lives there!. :-)

      In New England outdoor wood boilers are increasingly being banned by local communities for the excessive pollution emissions they put out when dampered-down.

      1. Peter L | | #6

        How bad is propane for the main heating source? In rural areas, natural gas lines are not around so many people use propane tanks that require propane trucks to drive and refill the tank.

        I am all for electric heat pumps (mini splits) for heating and removing ALL fossil fuels for heating the home.

        1. Stephen Sheehy | | #7

          Here in Maine, propane is about twice the cost (per btu of output) of a heat pump.

        2. Expert Member
          Zephyr7 | | #8

          Propane itself burns very clean, and it’s usually a byproduct of oil production so you’re essentially using what would otherwise be a waste product so in a way, it’s green like that.

          Trucked fuel deliveries will never be as efficient as delivery by pipeline though. If propane is all you have, it’s probably better than using heating oil or wood in terms of pollution, but a heat pump running off of grid electricity will likely be your cleanest overall option, and possibly also the cheapest.

          Bill

  4. Walter Ahlgrim | | #11

    You can only change someone’s mind after they open it to you. The guy you were talking to is clearly no open to change.

    “When will this tired and false narrative of leaky homes be finally put to rest?”

    Before you decide the guy is an idiot, remember his ideas have stood the test of time buildings using his strategies building have survived for hundreds of years. All our new fangled sealants, insulations, water and air barriers have been around for what 20 years? Will peel and stick window flashing still be waterproof in 200 years?

    Most of us on this site have a common goals and points of view. Other people different goals and points of view and use different strategies accomplish them. His strategies are only wrong if you are trying to accomplish your goals. Our goals were more popular when oil was $120 a barrel than it is now at $50.

    Walta

  5. thrifttrust | | #12

    The problem with the leaky house is good argument is that it only holds in a completely uninsulated wall. In this case most of the "insulation" is the sheathing. As such the inside surface of the sheathing will always be above the dew point. When the wall cavity is insulated the sheathing temperature drops below the dew point and the insulation itself absorbs and holds condensed water, but the insulation slows air movement and drying. As soon as insulation is introduced into a wall system it is imperative that air movement be controlled.

    1. Expert Member
      Rick Evans | | #13

      Exactly! This is the major reason that the Passivhaus Institutes stipulate air-tightness requirements. It's not so much because of heat loss but to ensure the safety/ durability of the enclosure/assembly over time.

      The thicker the wall/ceiling/etc the more serious this risk becomes.

  6. John Clark | | #15

    When energy becomes more expensive attitudes will change. It's why for example that for the 20th year I'm currently working in a cold drafty room because I can't convenience my spouse that our improperly installed/sized 20 yr old windows needed to be replaced rather than the downstairs furniture, rugs, carpeting. For 20 yrs I've been told to put on a sweater.

    1. Peter L | | #16

      John,

      Well, you probably know by 20 years of marriage that a happy spouse makes for a happy marriage. Your happiness is inconsequential :)

  7. dmmoore | | #17

    Peter, I have seen several of your posts about building a small guest house for cheap. Can you point me in the right direction for all the steps (design, materials, etc)? Trying to be my own GC. Thanks

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