Hybrid Car – More Fun with Less Gas

Re: Plans for a passive solar, energy efficient two-story duplex?

register ::  Login Password  :: Lost Password?
Posted by LarenCorie on July 12, 2003, 11:29 pm

 >> ...I hope to find plans for a passive solar, energy-efficient two-story

Well, I agree with the basic premise, but feel that in building design,
for the real world, it is necessary to juggle thousands of factors, most
of which are far more important than making the Solar design "easy"
I've used the Solar/sailboat analogy a lot, but I see sailboats coming
in a myriad of sizes, shapes and "styles," from sleek catamarans like a
Nacra, to classic sailing ships, to exotic/quaint lateen rigs on the Nile.
All serve a primary function that is higher than their sail performance.
Very few people want a sailboat that is just a racer.  Sailboats get
designed from the standpoint of their human related functions, before
their "rig" is ever designed.  I have always found that approach to be
the most valid with Solar housing as well.  Few folks want to live in a
structure which has its main purpose to be a heating machine. That's
just bad architecture, and would be a cop out.  It's also too easy, and
boring.  With talent any style can be achieved, and still have a good
passive Solar house.  After all, there is a whole lot more, even to
the thermal aspects of design, than just heating.  It may not be easy
to achieve, but it is definitely the thing to do.  Now, what climate is
this duplex intended for?  Is it intended for an existing property?
The function that the form needs to follow is a "home."  That means
different things to different people, but it is usually their biggest
investment, their sanctuary from the outside world, and an important
expression to that world of "This is who I am"  Your "home" should
enhance your lifestyle, not dictate it. The house is to serve you. You
are not there for it. The same goes for the designer.  If a designer
is to know freedom, then s/he needs to understand the client's needs,
wants, and inner desires well enough to satisfy them, and go beyond
that into the realm of creativity.  Passive Solar doesn't just heat.
It brings you in touch with the climate, the seasons, and the light
of the day.  It molds them into a meaningful sensory experience.
Done properly, it is Art that far exceeds the technology.

Most anything you want.......when it's done well.

How inexpensive?  Budget is not just dollars.  It includes a collection
of assetts that include influence, skills, time, friends, patience, tools,
lifestyle, creativity, temperment, family, confidence....etc. Just about
anything is possible......but how well does it balance with probability,
and your chance of pulling it off?

I usually refused to design for people who didn't, at the least, do
their own general contracting.  Owner control over expenditures
and adjustments is the first step toward keeping costs down.
Actually hands-on owner building is further step.

           "Necessity is the mother of invention"

           "Where there's a will, there's a way"

I like the challenge of a design where the clients have opinions
and preferences. The end results always have more personality.
No "constraints" is like a novel without a plot or conflict.  The
hero ends up boring and lifeless, with little substance.  Radical
Solar is a valid theme, but it's not a theme that hardly anybody
wants as the central motif of their home. It's better as a smaller
contributing part, which augments their freedom and insight, not
dominates their space.  There is way more to architecture than
heating, especially when the goal is creating a "home" environment....

I think that its aesthetics are a lot more flexible than
most take advantage of, but I find the system to be
sort of "odd", when there are ways to build a wonderful
house that are much closer to conventional techniques.
I like beam and decking floor systems, and simplified
post and beam for large expanses of glass and sunspaces,
and I find a lot of clever ways to play the structure, the
floor plans, and the mechanical systems, so that they will
go together more elegantly.   I have always found wood
frame construction to have value that's worthy of working
with (with certain tweaking).  I use some pretty unusual
details, but the materials are generally standard, easily
obtained, familiar to workers......and aceptable to both
banks and building departments.

Definitely a "style" that has its place, and won't work
at all in others.  Quite a bit of labor for a house that
often has limited resale value.

I think that is generally a smart approach, with certain qualifications.

I couldn't find the original post, and don't know the poster's name,
but I hope you can answer my few questions, and keep this going.
By "duplex" do you mean upper and lower flats, or side by side
like row houses, or clustered like condos?  Is this in the city,
or on acreage?  Info inflow please ;O)

BTW.......I'm really into tiny houses.  That's my new
obsession.  I hope to move out of my own "big" home,
and into the first in a series of tiny off-grid ones
this winter.

Laren Corie
Passive Solar Building Design Since 1975 (retired)
"Art To Live In"

PS.....Hi Nick!  Sorry for using your response as a spring board,
but I'm really into the sailboat analogy (used it in my very last
Solar post, about a week earlier), so I just couldn't help playing
off it.  I definitely look at people who have a "style" in mind as
a half full glass, not a half empty one.

Posted by Nick Pine on July 13, 2003, 12:04 pm

Depends on what we mean by "solar design" and "easy." A typical passive
solar house might be 30% solar-heated. PSIC says an excellent one in the
Northeast might be 40% solar heated, following all of their mass and glass
guidelines religiously. These are fake solar houses, since they are mostly
heated by something else, eg gas or oil or wood or electricity. Calling them
solar houses is fraudulent, and it disguises the difficulty of designing
a real one. Homeowners who live in them sadly twist their perceptions into
thinking they are more than 40% solar heated. ("We only use the woodstove
for about an hour a day.")

Some people say a solar house is "one with no other form of heat."
Removing the furnace makes fraud more difficult...

It seems to me that making a house more than 90% solar-heated is very
difficult, even on paper, even it that is the only goal. They are the
America's Cup boats, with fewer rules. There are very few houses like
that in the Northeast. Those of Norman Saunders come close. Would that
a few more people make this a serious goal.

A fake one. "Look at all that glass. It's a solar house."

Good question, but I suspect the OP is a dilettante.

Right. Forget the energy part. Consider the Feng Shui and soothing colors...

  My message to architects and engineers is: Look at the whole picture.
  In the trade press recently, there was an article hailing a custom,
  9,000-square-foot, architect-designed house as the latest in
  environmentally responsible design. Its principal claim to fame
  seemed to be the use of natural, nontoxic finishes on the woodwork.
  In the rush to commercialize "Green Architecture," no one noticed
  that this house consumes more energy than a small New England town.

  If your goal is trying to build an environmentally responsible building,
  you're missing the whole point if you get all lathered up over a
  nonvolatile natural finish on the handrails, while you're connected
  to a plutonium generator down the road. It's the same "out of site,
  out of mind" again, with a new face on it. "I'm doing all I can for
  the environment, my architect specified beeswax on my new woodwork--
  someone else will just have to figure out what we're going to do
  with all this radioactive waste"... and acid rain and oil spills and
  global warming and ozone depletion and unhealthy air quality and...

  You hear a lot about sustainability these days. I've been at this
  since 1973, long enough to be certain that, without addressing the
  energy issues, you're in the weeds. All the fuss over "my milk-based
  paints transported in from Europe" is just a myopic distraction from
  the issues that really matter on a global scale. True, natural-based
  finishes are desirable, but they fall far short of the answer.
  Establishing an energy infrastructure based on renewable resources
  is a necessary and fundamental precondition to establishing a
  sustainable society or to achieving sustainability at any scale.
  If you are not addressing the energy issues, don't even pretend
  that your buildling is environmentally responsible.

       Architect Steven Strong in
       The New Independent Home by Michael Potts, Chelsea Green, 1999

Well sure. We need natural fibers, and drama.



Posted by Nick Pine on July 26, 2003, 11:27 am

Would you call this a "solar house"? :-)

   Every day is sunny for George and Charlotte Britton of Lafayette Hill.
   And for Vivian VanStory of North Philadelphia. VanStory's 1,280-square-
   foot house uses 60 percent less energy than a comparably sized dwelling
   built to minimum energy-code standards. The Britton's 2,900-square-foot
   house is blessed with energy bills 20 percent lower than one of comparable
   size... The design of the house incorporates "passive" solar principles.
   There are large double pane windows and sliding glass doors on the south
   side. Inside, tile floors and a Trombe wall absorb the sun's heat during
   the day and radiate it at night... A stone fireplace on the south wall
   of the living area provides additional heat during colder months...
   Britton said... "We have a fire every day of the winter."

$.00. Then again, I live next door.

Traverse City looks tough. NREL says 490 Btu/ft^2 of sun falls on a south
wall and 370 on a horizontal surface on an an average 25.4 F December day
with an average daily high of 31.2. E/W/N walls get 240/230/160.

Richard Nelson proposed building four houses around a two-story
sunspace/courtyard with a bubbleroof over hanging gardens and
tennis courts and swimming pools in cloudier parts of Canada.

Northern Michigan might be a good place to put up a quonset-style
polycarbonate sunspace between two "normal" superinsulated houses.
It could provide warm air for the houses on an average day and
make hot water and store cloudy day heat with a well-insulated
tank full of warmer water.

A 32x32x8' tall house with R48 walls and ceiling and 96 ft^2 of R4 windows
with 50% solar transmission and 15 cfm of natural air leakage would have a
thermal conductance to outdoor air of 1024ft^2/R48 = 21 for the ceiling plus
24 for windows plus 20 for walls plus 15 for air infiltration, a total of
80 Btu/h-F. It would need 24h(65-25.4)80 = 76K Btu/day of heat in December
in Traverse City, which might come from 22.3 kWh/day or 669 kWh/month of
indoor electrical usage, with no sun at all.

Solar heating a house like that 100% in Northern Michigan looks easy, IF
it remains a non-zero priority, after the Jaccuzi, Palladian windows,
Corian countertops, and similar crap.


Posted by Ecnerwal on July 27, 2003, 1:52 pm

That's a very tight house, Nick.  0.109 ACH. I believe that you'll want
some active ventilation to make it livable, though hopefully some
benefit can be gained by using an air to air heat exchanger on the
active ventilation - but I have not tracked down real performance
numbers for those, yet. I need to.

I've been running numbers for my 24x48x21 foot two story shop, located
in Southwest Vermont (Albany NY is closest NREL data site).

R33 SIP walls (should be tight), R10 stemwall (aboveground 18",
insulated to the footings 4 feet underground - at least it will be later
this week, I hope - my labor force is wasting time on the computer this
morning). R38-ish ceiling, R5 or R10 under the slab (not sure if R10 is
worth it with the frostwall already insulated to R10, and drainage to
keep the soil inside the frostwall dry). The slab is not intended as
"passive solar storage", it's intended as a workshop floor, and will
have radiant heat tubing embedded. The benefits of high temperature
water storage have been successfully beaten into my head here over the

There's a 10x10 R17.5 door, and a mandoor which, if typical of mandoors
(R3.5), will suck almost as much heat from a 3x7 door. Perhaps I can
find a better one or improve the one I have. The windows I've looked at
are R2.9 for double-insulated Low-E II argon fill; I'm currently
guesstimating 192 square feet, skewed to the south. I recall seeing some
news about R10 windows, but I expect the cost is way out of line.

The overall building envelope has an aggregate R value of 12.27 (434
Btu/h-F) (including floor to ground, which does not have quite the
temperature difference to put up with that the walls and roof do).
Neglecting the floor, the overall R value jumps to 20.4 (204 Btu/h-F)

However, better doors and windows quickly get lost in the noise, because
already the ventilation heat requirement exceeds the radiation heat
requirement, at a ventilation rate of 1 ACH.

On a -20F day (68F inside - extreme day for gesssing size of heating
supply), the radiation heat loss is 24,401btu/hr, ventilation is 36,758.
(I'm crunching the ventialtion heat loss using numbers I was given in a
fish-farming course - 1 lb of air at 13.9 cubic feet, specific heat of
air at 0.24 btu/Lb*DegF). So rather than run up the cost of the windows
and man door a lot, I'm looking at an air-to air heat exchanger as being
the most important next thing to consider spending money on for

I have not yet run numbers on window gain. One 48x21 wall is more or
less due south (within 5 degrees) with deciduous trees providing some
summer shade, and less (but still a fair bit) winter shade. I like the
trees, I don't plan to remove them, though some thinning might happen. I
intend to turn much of that wall (other than the windows) into a
low-cost solar collector.

Cats, Coffee, Chocolate...vices to live by

Posted by daestrom on July 27, 2003, 4:22 pm

Of course, there are some 'UPers' that consider Traverse City 'south' ;-)
Been to school in Houghton MI.  Halfway out the peninsula into Lake Superior
means a very *large* amount of snowfall.  And considering it is much further
north than TC, it would be more of a challenge.

Most people think TC is in 'northern Michigan' because they don't consider
the upper peninsula.  By land area, more than half the state is north of TC
(my hometown included).

Try Marquette or Houghton, or just Sault Ste Marie...


This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread