[Greenbuilding] Passive House Overheating

[Corwyn]

On 8/16/2012 7:41 AM, John Straube wrote:
> Corwyn, I was joking about the hot humid climate of Maine.  Relative to
> most places in the US, it is NOT!

...And even put in an emoticon.  Sorry I missed that.

> In many houses, people dont know or
> want to bother opening windows at the right time. Based on the my walks
> through suburbia across the US in the early evening when it is cool
> outside and the AC units on house after house are running, I would
> venture to say this is the vast majority of people.

Possibly.  But the same could be said for heating.  At which point, we 
are both out of a job. :-)  If one believes that either energy is going 
to get scarce or costly, or that reducing usage is a good in itself, 
then accepting what the vast majority of people (in the richest most 
wasteful country in the world) do, is not going to solve anything.

If we start at the other end, and assume everyone starts with no status 
quo, we can calculate, for example, how much oil everyone gets.  This 
amounts to 1/2 gallon per person per day (at current production levels). 
  Given that allotment, do you think the majority would be spending 
theirs on air conditioning?  Or would they be looking for some other 
solution to the heat.  I want to be the guy with that solution already 
in hand.  While 'bother', might be hard to overcome, 'know' is well 
within my capability.  I am teaching 'energy efficiency by knowledge' 
every time I discuss the subject.  Someone with more influence could do 
much more.

> To me there is not much doubt that you can tweak a design to solve one
> person/family's personal preference and tolerance for high temperature.
> But if we are to make a real differences to millions of new and retrofit
> homes, it seems the safer bet is to make designs that require less
> effort to operate, assume normal comfort tolerances, and assume people
> are not always home and willing to operate components. Yes, this is not
> the least resource solution imaginable, but it is more likely to be a
> real step towards a massive shift rather than a few really low energy
> houses.

If people are unwilling to operate components, we should simply automate 
them.  However, IMHO operating a few windows is no more effort than 
operating a few air conditioners.  Nor do you need to be home at unusual 
times to do so.

But, if we reach a point where we have exhausted all design options 
other than low SHGC glass, is it really the case that that is the lowest 
energy solution for Chris Corson?  Even if he uses a AC to achieve 
comfort, he is going to need around 1.5 MBTUs of cooling (based on the 
difference in cooling degree-days vs heating degree-days here) while 
losing 5 MBTUs of winter heating.  So, I wouldn't recommend lower SHGC 
glass.

We aren't going to make a real difference to millions of homes by 
treating them all the same.  That is how they got the way they are in 
the first place.  Energy efficiency is a *local* issue.  This is, I 
think, exactly your point about Passivhaus (with which I heartily 
agree).  We can never hope to find a solution that works for everyone, 
everywhere.  My hope is that we *might* be able to find a *process* 
which is capable of finding a solution for everyone, everywhere.


Thank You Kindly,

Corwyn
Topher Belknap


-- 
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.greenfret.com/
topher at greenfret.com
(207) 882-7652