[Greenbuilding] rigid foam inside Larsen truss

[Reuben Deumling]

>   Seems excessive for your relatively mild climate.
>

So understood, yes. But all the economic formulas and the economistic
thinking underlying them which suggest that there is an optimum effort
arose in a period of material profligacy, when fossil fuels were cheap and
no one had ever heard of 'leave it in the ground.' The way I see it,
finding ways to be more parsimonious with fossil fuels, more efficient
isn't really all that relevant anymore. We need to be done with them
altogether. To move beyond oil and gas requires entirely different
calculations, a different mindset. I'm not saying that my idea of a
cellulose/foam/cellulose sandwich is wise or prudent or even that it
conforms to this post-fossil fuel era, but I would like whatever wall I end
up with to, and am more than happy to learn that foam is excessive and
unnecessary, even when bought at a discount yard. In fact, George's recent
elaborations already persuaded me not to go that route.

Overkill is UN-GREEN, and simply wasteful.
>

Hm. That is an interesting way to look at this. I don't think I agree, at
least not across the board.
I generally operate on the *if it is worth doing it is worth overdoing*
principle.
My time is free, my dumpster dived lumber is free, my nails come from a
lifetime supply pulled from houses I've restored, and straightened. I do
occasionally buy building paper and flashing tape and cellulose bails, but
in the grand scheme of things...
,

> It might be greener to spend a little more on 100% renewable electricity,
> than
> on redundant insulation.
>

Not sure why this would be an either/or thing. I've been using 100%
renewable electricity (for what it's worth) for twenty + years. Though I
have never heated with electricity and am not about to start doing that,
notwithstanding some recent shifts in thinking.

With extreme walls like that, you would likely be looking at nearly all
your heat loss going out windows, doors, and ventilation, and the last few
inches of cellulose simply not having any payback, at all, for the time and
money they cost you.

You like payback; I get that. But I think of payback as for people who need
convincing, who hire contractors, who go to building supply houses or the
big orange box. Most of what I do doesn't align with the worldview that
gave us this payback logic.


So, instead of the minimum 100 year payback (calculated above) you could
>> likely be looking at more like 200+.years, to break even.
>>
>
I mostly try to steer clear of the money economy. I cut my own firewood
from oak trees that blew down decades ago; the annual cost for my heating
system is a few quarts of chainsaw gas and oil, and about five gallons of
diesel for the truck that I haul it in; my long term goal is to shrink my
1-1/4 cords/yr firewood consumption to maybe 1/4 cord, and since I hope to
live another, oh, 35-40 years in this house, the fuel savings, not to
mention the greater thermal stability, extra helping of comfort in our
increasingly hot summers, etc. seems to me well worth the effort in
constructing what you are calling extreme walls.

you could likely buy a used Nissan Leaf, electric car, and move most of
your driving off your fossil fuel list, and save yourself enough money to
fund other energy saving projects.

But I don't have a car. Buying a car, even the kind that green folks feel
good about is by my calculations going the wrong direction for someone who
gets along just fine without a car.

Remember, your house envelope is not the only place you use energy,
> and now there are good options to improve other areas of our energy lives.
>
Yes, that is correct. I'm working on those other areas as well. But this
one has the most obvious overlap with the subject of this discussion forum.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20180107/d688a586/attachment.html>