Oops. I've encountered the read-before-you-send problem. In my third
paragraph I meant that the dewpoint is generally LOWER than the coldest
envelope component, not higher. Apologies.

David Yuill

Another option is to think about the DOAS route. This may lower the cost of
providing dehumidification of the outdoor airstream, if you're trying to
maintain a dewpoint indoors that is lower than the dewpoint outdoors under
some conditions.

Chris -

We generally study these building envelope moisture-control issues with
WUFI - a program that uses the hygroscopic properties of component
materials along with moisture and temperature environment variables to
determine if there is potential damage from moisture and condensation.

Dave Bryan
AIA, LEED

I should also point out that the DOAS is also applicable in cases where
you're after a dewpoint that is above the outdoor dewpoint. I may have left
a different impression in an earlier message. It can be much cheaper to
dehumidify a portion of the airstream that is already near saturation than
to dehumidify mixed air.

Since I live in a "heritage building" (100+ year old balloon-framed
house that began as the bunk-house for hired hands and hasn't gained
much insulation since), and I've worked in historic preservation firms
for years, I think a lot on this subject.

Everyone who replied to this subject was mostly right on target, but I
want to add my two cents in re-iterating the cautions in doing poorly
conceived energy retrofits to leaky old buildings without understanding
the building science and how it applies to the particular building. One
should at least figure out where the dewpoint falls in the wall in the
existing structure as well as the proposed retrofit, where the biggest
air leaks are in the building envelope (an infrared camera used during a
blower-door test makes this very graphic), and how one is going to
retard the passage of moist air into the portion of the building
envelope that is near or below dewpoint, and how you will encourage all
portions of the building envelope to dry to either the interior or
exterior faster than they are exposed to moisture. If one does a
haphazard job of tightening the structure and adding insulation, one can
easily cause a century old building that was in decent structural
condition to rot away in less than a decade, and/or make its occupants
deathly ill when you concentrate the humidity escaping into a few
locations and even increase the temperature in the building envelope to
the perfect conditions for micro-organisms to proliferate.

This "heritage" building I'm in (like most such) is a working holistic
building/energy system when operated as originally designed. It is
extremely drafty in winter, so the moisture we generate by breathing,
showering, cooking, etc diffuses right out through the envelope. Yes, it
probably condenses on surfaces within the walls as it does on interior
window panes, but there is so much air movement through the envelope
that it dries out again almost immediately, plus it is probably too cold
in the walls for mold and rot to grow. Part of what made this house (and
many other buildings of its vintage) last so long is that the standards
of human comfort were much lower when it was built. Typically only one
room on the ground floor was heated (with wood) as we are doing now (the
unheated rooms surrounding the heated one reduce heat loss and prevent
ice damming), and humidity levels in winter were very low, due to high
air leakage and a dry heat source (and people bathed infrequently
instead of showering daily). If all future occupants could be content
with cocooning near the woodstove and could deal with the nose bleeds
from dry air as we do, this building could probably last another century
and use relatively little energy to get through winter, but that is
unlikely in the extreme.

Consequently, though I preach energy efficiency at every turn, I've not
done anything to the "heritage" building I live in yet, mostly due to
other unrelated changes in its environment that now make the home an
undesireable place to live. But even if this home was desireable to
salvage, I'd wait until I had sufficient funds to retrofit the whole
building with a super-efficient retrofit such as one that would meet or
at least approach the Passive House Standard (see www.passivehouse.us
&www.passivehouse.com), else I could easily make things worse instead of
better. From all of my study and research, I've come to the conclusion
that unless one is prevented by historic preservation restrictions, the
safest/ best energy retrofit to old buildings is to wrap them on the the
exterior with a new air barrier which must be carefully sealed to the
highest performance windows and doors available (preferably ones that
can meet the Passive House certification standards) to create a very
tight continuous air barrier, which must then be wrapped with a
continuous superinsulation layer on the exterior of the air barrier. The
cheapest solution is typically to decide that basement and crawlspaces
are outside the conditioned space (air barrier on underside of original
joists, with superinsulation below that), and move all mechanicals and
plumbing into the conditioned space if possible, superinsulating
plumbing/ mechanical runs that can't be moved inside the insulated
envelope. One can deal with insulating basements and slab on grade
construction, but it is much more challenging and costly to do it well.

I say it is safest to energy retrofit on the exterior because one can
often attempt to replicate the original facades on the new exteriors
easier than one can succeed in creating a tight air barrier on the
inside of the insulation layers if one is limited to retrofitting on the
inside of the building. But if you are forced to retrofit from the
inside, you'd better check for concentrated air leaks thoroughly with
infrared camera and blower door test until you get a VERY tight
building, and calculate the temperature at that air barrier to ensure
that it is above the dewpoint. The Passive House Institute has
demonstrated that even if you are forced to create the air barrier and
to superinsulate on the inside (this inevitably results in more air
leaks and lots of thermal bridging), superinsulating to the Passive
House Standard typically prevents condensation on the interior surfaces
of thermal bridges because it attenuates the path of heat loss which
typically raises the interior surface temperature of the thermal bridge
to above the dewpoint. But retrofitting to the Passive House Standard
often costs as much as building new, and needs to be done in one
building season - incremental "improvements" can be worse than doing
nothing, as I described above.

Best wishes if you are trying to salvage existing buildings, and keep
your professional insurance up to date,
Christina

The original messages are below:

Dear Bldg-Sim community,

Many years ago, I used "A Simplified Energy Analysis Method" software, which
was a bin analysis energy modeling tool. I'm interested in finding it
again, primarily for existing building models, but can't locate it.

Has anyone got current contact info for that program?

Thanks in advance!

James V. Dirkes II, P.E., LEED AP

Hi JV;

This question was asked and resolved about 3 years ago.
As I remember the person who had the Program only had 5.25" Floppy Disks.
We still have 5.25" Floppy capability but we are about to shed our old
formats
support, no one ever calls for it. We have QIC-120, QIC-250, 3010,
TR-1, TR-2, TR-3, TR-4
tape capability. We have ZIP-100, Zip-250 capability. We expect to
abandon this already offline hardware in
the next 30 days !!! We have not had 8" floppy capability for several
years. There are 5 or 6
different ways to get the timing holes in 8" floppy disks so unless you
had DSDD's things could
be sparse.