Components - How we (plan to) do stuff
Almost all of our design components (except cooking, drying
clothes and auxiliary heating) require either no energy or
use energy that comes from a renewable source like solar,
wind and water.
Read on to learn more about how we plan to heat
& cool our house, get fresh
water & hot water, cook
& wash, generate & store electricity
and see when it's dark & entertain. At the end of this page you'll also find a description of our floor plan design process and the thinking that went into the design of our shelter.
Passive Solar Design
- Orientation - the long side of our 24'
x 36' house, faces due true south, thus maximizing the potential
for solar gain (and potential future solar energy harvesting
on the roof). That also means that our gables face east
- Glazing - All our windows will have a
U-value of 0.30 or better, since here in south-east Minnesota
our heating season is much longer than our cooling season (it's May 11 and the heating just came on again...with high temperatures in the 40s ouside...).
Approx. 55% of the glazing is on the south side with a high
SHCG (solar heat gain coefficient) of 0.45 to 0.55 giving
us enough heat in the winter from the low standing sun (see
"overhang" below). The east and west side windows,
35%, will have a moderate SHGC of 0.35 to 0.45 to allow
for an early start through the east windows (25%) and a
last boost on the west (10%). The north windows (10%) will
have a U value of 0.20 or lower and the lowest SHGC we can
- Heat Storage - We will have a 4-6"
cement slab as the main level floor (if we can find an architect/builder
team that can 'slab' that on top of our basement). The slabe
will serve as the heating battery storing the heat throughout
the day and releasing it during evening and night.
- Heat Circulation - To increase the capacity
of our heat storage and to distribute the heat evenly throughout
the house, especially the basement and the north rooms on
the main floor, we plan to let the radiant floor heat circulate
with no additional heat source. Pending some outstanding
calculations that might even help us to decrease the thickness of the cement slab.
- Concrete-Shell -
- Overhang - all around the house, but especially on the south side the roof extends beyond the walls to create a substantial overhang. On the south side the overhang provides sufficient shade in the summertime, as the sun stands much higher in the summer than in the winter. In the wintertime, according to my calculations, the sun will actually penetrate the living almost to the back-side of the living and dining room.
Discuss our passive solar design plans & ideas on our
Radiant Floor Heat
Our current design really does not allow us to put any more
glazing on the south side. Based on some percentages we read
in one of the standard books, we probably do not have enough
glazing for the whole main floor, though the glazing amount
just feels right and I am much more concerned about overheating
(and the heat loss associated with many windows) than underheating.
Incidentally my parents in Germany have radiant floor heating
(since 1978) and are tremendously happy with it. To my knowledge
there have been no problems with the system or the hoses in
now over 25 years.
- Pumping - On of the many beauties of
radiant floor heating is that you really don't need much
energy for pumping (or heating). A low-flow 24VDC pump should
- Heating -
- Zoning - I am still working
Currently I plan on putting radiant floor heat in every room except the pantry (I'll probably just heat the space in front of the wardrobe by means of the connection between the bathroom and the kitchen).
In the basement all rooms except I plan on putting it in the music studio, movie room, animal den and garden tools (and maybe a few pipes through the storage area).
On the 2nd floor probably only the two bathrooms will get radiant floor heat - the passive heat "sucked up" through the . On the other hand I'll probably run a little calculation to calculate the additional cost of the two bedrooms...at least then I have the option to do hook them into the system later...
One of the areas that I haven't addressed yet is how to get the hot water from the basement to the 2nd floor...that is quite a rise and requires a pump with a "high-head". Maybe a 2nd warm water reservoir with heat exchanger in the attic space could be the solution.
We plan on having the masonry stove built by "Gimme Shelter Construction " a company located in central Wisconsin that builds masonry stoves designed by a guy from Toronto, Canada.
- Cellular Blinds - In our current house,
a Victorian from 1890, after a heating bill of $530 for
January 2001 we spent approx. $750 on cellular/honey comb
blinds to shade 12 of our 32 windows (6 already had aluminum
blinds). In subsequent years, granted with milder winters,
our heating bills dropped dramatically and temperature-comfort
increased significantly (we also invested in a thermostat
with a timer). So naturally we plan to employ cellular blinds
as a means of keeping the heat in (and keeping the heat
out in the summer, see below under 'cooling').
I define passive cooling as any means that avoid
over-heating of the house that do not require any energy or
- Overhang - On the south side we have
a 2'-2.5' roof overhang to shade our solar collectors (fancy
word for windows on the south-side...).
- Low heat gain - On the east & west
side we want to use windows with a moderate SHGC (solar
heat gain coefficient) of 0.35 to 0.45. Especially in the
afternoon on the west side that will keep the potential
heat gain low.
Active Cooling on the other hand requires a certain amount
of energy (even if it's just me getting my rear end of the
chair to lower the blinds or open a window). We will not employ
any means of cooling that require large amounts of electrical
energy, such as an air conditioner. In our current house,
built in 1890, we have been very comfortable during the past
3 summers except for maybe two or three days.
- Natural Air Flow - During our floorplan
design we have placed the doors and windows in a way that
allows virtually all corners in all rooms to be vented by
opening two opposite windows and any door in between.
- Cellular Blinds - In the summer &
fall the cellular blinds, especially on the west windows
in the office, will help to keep the afternoon sun out.
- Sleeping in the Basement - Based on our
experience in our Victorian House 20 miles west of Licht
'n Stein, there are only 3-4 days in July or August where
it gets really warm. So if we can't get the house cool,
we can always go down in the basement and enjoy a cool night's
sleep down there.
Why Rain Water?
During our initial research of the "total cost of ownership" prior to us making an offer to buy the land, we obtained an estimate of about $22k for drilling a 550-600 ft. deep well (165-180 m). This, and the fact that our friends Sarah & Kirby as well as the folks at Dream Acres are living quite comfortably with rain water collection, provided enough incentive for us to consider using rain water as our only source for drinking water -- including water toilets and showers. Besides, as with many aspects with our project, we wanted to go back to basic methods of sustainable and environmentally living and learn how to live comfortably within the constraints that nature provides us.
But the cost and "learning experience" were not the only factors. In addition to those benefits, rainwater is softer because it contains less minerals (as it has not sickered through hundreds of soil layers). Whether it contains less pesticides and herbicides remains to be seen (and tested). At a recent Dinner on the Bluff series event, we learned that even in Minneapolis the lakes are already poisoned with pesticides that are otherwise only found in rural areas. Further tests revealed that they had gotten there through...the rain. (see "Filtering" below).
Rain Water Collection
Roof Area: Yield
The floor area (inside measures) is 36' 8" by 38' 8". The width of the walls will be 11" and the overhangs are as follows: East & West 2' 9"; South 3' 6" and to the north the "drive-through" overhang of 14'. This provides a roof area of 44' x 58' (13.4 m by 17.7 m) or 2,552 sq.ft. (237 m2) that will yield approx. 1,430 gal of water per inch of rainfall at 90% yield (you can use google to ask: "44 * 58 / 12 * 0.90) cu ft in gal"). At an annual average of 40 inches of rain for the Rochester area, this yields about 57,200 gallons a year or 156 gallons (594 l) a day. Even in a dry year with 24 inches, that is still 94 gallons (355 l) a day.
The following table summarizes all calculations:
||= 2' 9" + 11" + 36' 8" + 11" + 2' 9"
||= 44' 0"
||= 3' 6" + 11" + 38' 8" + 11" + 14'
||= 58' 0"
||= 44' 0" * 58' 0"
||= 2,552 sq.ft.
||= 2,552 * (1/12) * 90% * 7.5 gal/cu.ft.
||= 1430 gal./inch
||= 1,430 gal./inch * 40"
||= 57,200 gal./year
||= 57,200 gal./year / 365 days/year
||= 156 gal./day
||= 2,552 * (24"/12") * 90% / 365 * 7.5
||= 94 gal./day
Rain Water Filtering & Storage
The dimensioning of our storage capacity was influenced by multiple factors.
Overflow & Fill 'er Up
As the above calculations showed, a single 2-3 inch rainfall can yield almost 4,000 gallons of water -- or about two-thirds or our storage capacity. So it is definitely thinkable and likely that we might have days where our cisterns are at capacity, at which point we better had thought of a way to divert the water (notwithstanding the option of taking some long showers or big bubble-baths).
At this point I have not completely thought through the best way. Maybe we'll put up some additional outside storage tanks under the deck to collect water for watering the garden. But ultimately we have to route the water away from the house (I don't think it would be good to flood our septic system).
The other extreme case (for the quality-inclined out there: I'm testing the boundary conditions ;-) is when to run completely out of water, which most likely would happen during the winter. E.g., if the last rainfall (that filled up our cisterns) was on December 6, we could run out of water by February 24, after 80 days, if we use an average of 75 gallons per day. To accomodate this scenario we need to add a "frost-free" filling pipe accessible from the outside (or, I was just thinking, maybe from within the garage). Then we can either get a milk or fire truck to bring some water or get one of those "truck bed tanks" to haul some water ourselves.
Washing & Drying
AC/DC - from DC to AC
Minimal but yet Sufficient
We initially started our house design by trying to come up with a space-efficient design that still provides comfort. Although we haven't read her book, you could say that we designed a "not-so-big house". Interestingly enough I just found out in an interview, that Susan is originally from the other side of th Atlantic (Britain) and also resides in Minnesota. I'm sure she'd have a few tricks up her sleeve to improve on our design, but for now we're quite happy. Anyway, I digress.
We quickly settled on a 36 by 24 foot (10.8 x 7.2 meters) floorplan for the main floor that included the living/dining area, a bathroom, kitchen, pantry, and an extra room for an office/library. To minimize space (but without sacrificing comfort) we had intended to have the garage in the basement (I definitely wanted an attached garage from which you could enter the house [for those of you wondering whether that isn't the definition of an attached garage I should mention that my father and I added an attached garage to our house in Germany, and though a garage wall and a house wall are attached to each other, you still need to walk into the house from the outside). During our initial review of the floor plan with our General Contractor, Andy Bunge, he shared a story of how he had designed his house as well as a duplex he just built in 2003 to be handicap accessible, because "you never know". So we took Andy's advice and went through a fairly extensive re-design that made all doors on the main floor 3 feet wide, the bathroom big enough to have a five-foot radius between sink, toilet, and bathtub, and the garage moved to the mainfloor (increasing our main floor size from 36 by 24 to 36 by 38 (10.8 m x 11.4 m).
Actually to move the garage up to the main floor had its advantages: it eliminated the need for excavation, potential retaining walls (although with the landscape given, we could have made it work) and the risk of having water run into the garage. Secondly we now have a nice, warm, 14 foot buffer to the north side of the main living space (which also nixed any attempt to put in windows on the north side ;-) that shields us nicely from the cold and from the frosty north winds. Thirdly we were able to gain a few feet for the upstairs rooms, thus deflating the somewhat tight spaces. A fourth advantage is the added roof space of at least 575 sq.ft. that
gives us a gallon of water more per day per each inch annual rainfall (40 gal/day for 40 in./year). And lastly, although somewhat unnecessary, it added a nice 480 sq.ft. to the basement, making enough room for the water tanks, the movie room, and room for a potential future music studio.
The Floorplan & Design
In the next paragraphs I'll try to describe our thinking behind the design of some of the rooms of our floor plan. The order in which things are described in here follows loosely the order in which the pictures are sorted in the corresponding photo album. Feel free to browse the pictures in parallel to reading the following paragraphs. Some descriptions might make more sense with the picture in mind.
The first thing that most people notice (besides the somwehat dramatic deck design) is that the living/dining room is very open and spacious. Obviously this is a direct result from our primary heating source, passive solar energy. Our glazing on the south-side takes up 24 ft of the 36 feet wall. But we are also lucky to be able to build in a spot where we have almost absolute privacy and do not have to be concerned about "exposure" or living in a fish bowl. Obviously this design would work less well in "suburbia" unless one would employ curtains.
On the north side you'll notice a large (14 foot) overhang that serves as additional rain water collection surface, shelter for firewood, and is a drive-through for accessing the west-facing garage entrance (see next section).
You'll also notice the roof's overhang, shielding the siding from the elements and especially on the south side, providing sufficient shading in the summer time (when the sun stands high in the sky during the day) to avoid overheating of the heavily glazed living room.
Another feature visible from the outside is the design of the "drive-through garage". This idea originated with the garage my father designed and built at their house in Germany. Albeit with the size of European cars, and the lack of space (my parents' fifth-of-an-acre lot on top of a landfill cost $100,000 in the mid 1970s...), my father could get by with an overall length of 8 or 9 meters (27-29.5 feet) and only one garage door; we played the "switching cars game" quite often. Originally we had only planned a "one car" garage which would have resulted in an L-shape floor plan. As I was "building" the walls in the 3D modeling program, however, I realized how unnecessarily complicated it would become to construct such a floorplan (including a much more complex roof line).Which then led me to the "drive-through" garage design with a door on either side.
For the time being we will use the garage for our pickup truck (which, according to our calculation uses approx. 30 mpg/per person since we mostly commute together at least 70% of the time) and for the tractor (a Kubota BX2230 - highly recommended). But the garage, at a length of 36' 8" (11.2 m), is now actually big enough for the truck plus a mid-size sedan.
No Traditional Entrance Door
The Garage also serves as our personal main entrance door, thus eliminating an often unused feature of houses, where most people enter the house through the backdoor. Besides the two garage doors on the east and west side, we added a regular door on the north side, a little off-center. This door will serve as a back-up entry and mainly in the winter as an access door to carry the firew wood inside from the north roof-overhang.
With a 2,000 ft (610 m) driveway that climbs about 300 feet (90 m), we're unlikely
Some of the more or less intentional unique design concepts include:
The biggest design challenge was to fit in the stairs from main floor to the basement. The stairs