[GSBN] The (not necessarily mechanical) ventilation debate

[RT]

  On Fri, 22 Mar 2013 "Feile Butler" wrote:

> I've been thinking about why has the mechanical ventilation debate been  
> getting under everyone's skin so much.

I too received one of those off-list emails (last week ?) from the same  
author but dismissed it as "noise" not unlike that which I and other  
air-tighties have heard ad infinitum before, decades ago.

It's interesting then that those advocating the "other side of the debate"  
on this list are quoting that off-list email (ie "impressions") rather  
than providing any real strategies that can be verified as being viable  
to, say, the average wise Grannie, who still lives in her  
poorly-insulated/air-leaky house that she and her long-dead husband built  
when they were young and now wishes that she didn't have to come up with  
the means to acquire the 10-plus full cords (ie 1 full cord = 3 face cords  
16" x 4' x 8') of firewood every winter which was a lot easier to do when  
she could still move around without a cane.

That 10 cord/winter number is not one I pulled out of my hat. I suspect  
that Frank Tettmer who is on this list probably knows a few living  
off-grid in his neighbourhood .

As stated in my first message to this thread, I found it troubling that we  
were only just now having this discussion on this List, a list whose  
membership is limited to building and design professionals.

Why ? Because if we're still having this "debate" it means that many,many  
professionals (ie not just some of the membership of this List) to whom  
the responsibility of making houses has been entrusted by their paying  
clients,  have been willfully making air-leaky, poorly ventilated SB  
houses for  the almost-three decades of this current SB revival . That a  
potentially large number of buildings and an even larger number of  
affected occupants of those houses.

"Troubling" because the resultant problems don`t manifest themselves in  
the dramatic fashion that some have suggested (ie "waking up dead some  
morning because a ventilation gizmo failed during the night) or as the  
sudden catastrophic structural failures that can and have occurred due to  
poor engineering.

The destructive processes occur slowly, over the course of a decade or  
more and people usually don't take notice until the sickness is  
well-advanced.

One can easily draw a parallel to the "Cigarette smoking" debate.

Despite the reams of evidence backed up by common sense and science that  
smoking is not a Good Thing, as late as the 90's of the previous  
millennium, millions of teens still feeling the invincibility of youth  
were still taking it up, much to the annoyance of those of us who had been  
there, done that and learned to know better.

And trying to convince the build-it-tight/ventilate right "non-believers"  
to quit leaking is just about as futile. They invariably find excuses to  
ignore the evidence.

I saw a cigarette package on the roadside that someone had tossed out of a  
passing car the other day.

The Canadian government requires that all cigarette packages have warnings  
and photos showing the deleterious effects of smoking. Also, all  
municipalities have enacted by-laws which prohibit smoking in all public  
buildings and in some cases even in outdoor public spaces.  These days, if  
you light up in a crowd of strangers, you're likely to be shat upon  
whereas not all that long ago, even some medical doctors smoked.

It's not a stretch to suggest that the same thing may happen with  
strawbale buildings simply because too many builders of strawbale  
buildings choose to ignore the evidence that making air-leaky and poorly  
ventilated well-insulated buildings is ill-advised.

Why is it not a stretch ?

Because it has already happened here, just across the river within  
eyesight of my home, over in Gatineau Quebec where the strawbale movement  
made some early inroads back in the previous millennium in the 80's and  
90's.

Back in 2004-2005 the City Council of that community of 300,000-plus  
proposed a by-law to prohibit the use of strawbale because of the numbers  
of sick SB buildings (ie moisture problems) that had been been built by  
those choosing to ignore the good building practise/building science that  
had been available to them.

I'm pretty sure that no one here was suggesting that mechanical  
ventilation was absolutely necessary.

What was being suggested was that well-insulated buildings need to be  
constructed so that air-leakage via the thermal envelope is minimised, not  
only for the health of the building but more importantly for the health of  
those occupying the buildings.

And like it or not, the corollary to air-tight construction is that an  
effective ventilation strategy must be provided to ensure the health of  
the occupants.

That's not some notion that a human with a high pucker factor conjured up.  
It's a reality created by the scenario.

As mentioned numerous times, how one chooses to provide that ventilation  
is entirely up to you.

No one here is twisting your arm to install a mechanical ventilator, let  
alone one with a heat recovery capacity exceeding the 90% (?) efficiency  
that the PassivHaus religion specifies. (As mentioned, I'm not a fan of PH  
and I'm pretty sure that if you kick WatJohn," PH "is more likely to  
emerge as an expletive rather than as a term of endearment).

The corollary to not having heat recovery capacity on the exhaust air  
stream with efficiencies in the 75-90-plus % range is that fuel must be  
consumed to make up for that lack ... for the life of the building.  And  
we all know that the life-cycle energy of a building far exceeds the  
embodied-energy by many magnitudes.  Right ?

For Felie and others who heat entirely with wood (+ sunlight + occupancy  
gains, as do I), you would be well-advised to ensure that your ventilation  
strategy (mechanical or otherwise) addresses the potential issue of  
combustion spillage or someone may very well get dead in the middle of the  
night -- "dead" of the of the "no waking up from" variety) ... or worse.

-- 
=== * ===
Rob Tom					AOD257
Kanata, Ontario, Canada

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