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By Stephen Heckeroth

This project is located on a four-acre parcel outside Albion, California,three miles east of the Pacific Oceanon a ridge above the fog. The home isa six-story, passive-solar water tower,planted between redwoods on threesides, yet open to the sun on the southside.

For many years, the clients had beenvisiting Mendocino, a historic coastal

mill town dating back to a time whenwater was pumped by the wind andstored in tanks located on towers forgravity pressurization. They fell inlove with the old towers and in 1979went looking for someone to designand build a tower for their family’sland on Caspar Point. The land at thissite was best served by an earth-bermed structure, so the tower waiteduntil a more suitable site was found.Construction began in 1993.

The owners asked for a house withvery specific proportions based ontheir favorite towers located in thetown of Mendocino, CA. They want-ed privacy on every floor, room for3,000 books and a collection ofAmerican oak furniture. Their wishesfurther included that the house be nat-urally heated, lit and ventilated, andhave as many spaces for reading anddining as possible. The house shouldbe practical enough to serve theirneeds, and whimsical enough to makethem smile. Function and fun.

The design response to the clientand the site was to nestle the 2,000-square-foot six-story tower and its350-square-foot attached green -house/sun space into the earth onthree sides and expose it to the southwhere a large clearing permitted goodsolar access. The tower house is heat-ed by the sun and cooled by naturalventilation. Roof-integrated flat-platesolar collectors provide the domestichot water. The pumps for the groundfloor’s solar-driven hydronic (radiant)heating system are powered by inte-grated photovoltaic (PV, or solar-elec-tric) modules. The height of the toweris mitigated by redwood trees on thenorth, east, and west.

Energy efficient building techniques

The basic concepts and systems insolar design are orientation to the sunand wind, earth coupling to takeadvantage of the earth’s (ground’s)more constant temperature, thermalmass to absorb, store and radiate heat,and an insulating envelope to keepheat in or out.

The tower is oriented towards thesouth for solar gain. A sunspace/greenhouse on the ground floorcaptures solar heat which naturallyrises through the house, warming alllevels.

Fifty yards of concrete were used inthe foundation and below-grade wallsfor both its structural and thermalproperties. The concrete providesthermal mass. The winter sun and asmall wood stove are the only sourcesof heat necessary for the tower house.Overhangs prevent the high summersun from overheating the tower. Whenwindows are opened, the house worksas a cooling tower. Hot air venting out

Above: Re-sawn redwoodfrom the local area was usedthroughout the house.

Left: The finished tower house sits quietly in the redwoods. Note how the overhangs preventdirect sunlight from entering the house during summer.

Right: The greenhouse/sun spaceis a good place to relaxand breathe oxygen-rich air.

A passive solar-heated tower houseIntegrates thermal mass, radiant floors, solar-heated water, natural ventilation, and solar-electricity.

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the hatch on the roof deck, in turn,pulls cool air into the lower floors.

The fact that the first floor is buriedon three sides takes advantage of theearth’s more constant 60°F. This tendsto cool the house in the summer andhelps warm it in the winter.

The R-values associated with fiber-glass insulation don’t take intoaccount plumbing, wiring, and fram-ing members, which lower the overallinsulation value. For this reason, rigidinsulation was used. R-19 rigid foaminsulation was wrapped around theentire structure above and belowgrade. This helps maintain a comfort-able temperature by slowing theescape of heat captured in the thermalmass, and making it available to theinterior space. R-11 foam insulationwas used underneath the slab to pre-vent heat in the radiant floor fromconducting itself into the ground.

Photovoltaic (PV) panels are mount-ed above flat-plate collectors on eitherside of the sun space/greenhouse.These supply the needed electricity torun the pumps for the lower solar-heated radiant floor.

Another set of flat-plate collectors isintegrated into the shed roofs of thefourth and fifth floors. These use ther-mosiphon circulation to move heatinto a hot water tank immediatelybelow the roof deck.

Screened windows open on twosides of every room to allow ventila-tion without using fans or blowers.The light provided by these windowslimits the need for electrical lightinguntil after sundown. Skylights havebeen added to two locations thatmight be otherwise dark. One is abovethe landing on the stairway up to thesecond floor. The other is a 6-foot by12-foot triple-glazed translucent roof

over the east end of the ground floorthat makes the basement the brightestroom in the house.

Resource-efficientmaterials

The house is built with a combina-tion of concrete and wood. The 50yards of concrete required to supporta 50-foot tower house would usuallybe buried under the ground, particu-larly on the West Coast where fewpeople have a basement. By designingthe foundation to form retainingwalls, the structural concrete servesthe multiple functions of foundation,thermal mass, and earth connection. Italso provides 300 square feet of com-fortable living space at almost noextra cost.

The above-grade structure is built ofthe same material that surrounds it.The redwood beams were made fromrecycled, re-sawn timbers, as wasmuch of the framework. The redwoodtrim was milled onsite from salvagedlumber. Tongue and groove, tight-grain, locally-milled Douglas Fir 2x6serves as flooring on each level andthe ceiling of the floor beneath. Thisconstruction technique exposes thebeautiful redwood beams whiledecreasing the overall height of thestructure by approximately one footper floor. It also saves several steps infinishing and trimming the ceiling andallows the heat to move slowly upfrom one floor to the next.

All the windows were purchased ata great cost savings from a salvageyard that deals in high-quality insulat-ed glass units. The house designaccommodated the fit of the windowsthat were available.

Runoff from the roofs is collected ina reflecting pond immediately to thesouth of the house. This pond is usedto irrigate terrace gardens furtherdown the south slope.

Appliances were chosen for theirlow energy use and quiet operation.All lighting is full-spectrum capsulefluorescents which require one quarter

September/October 2000 Backwoods Home Magazine

Right: Overhangsshade out the summer sun butallow full use ofthe winter sun.

of the energy of incandescent lightbulbs. Low-flow plumbing fixtureswere used to minimize water usage.

Many of the Mendocino water tow-ers that the home imitates have sur-

vived over 100 years on much lesssubstantial foundations. This homeshould last at least as long.

A healthful living andworking environment

The owners enjoy a quiet and natur-al living environment. Their warmth

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Left: The top soil from thebuilding site was carefullyseparated and saved for agarden site

Right: Foam insulation andwire mesh are added. Thehydronic heat pipes weretied to the mesh prior to

the pour of concrete.

Left, above, & right:The foundation forthe tower serves asstructural and thermal mass andprovides 300 squarefeet of comfortableliving space.

Above: The entire outside of thehouse is wrapped in an insulatingenvelope.

Right: The first and second floors under construction

Right: The finishedpassive solartower house

September/October 2000 Backwoods Home Magazine

comes from the solar gain propertiesof the structure and the naturally ris-ing heat that results. Ventilation isachieved by the opening and closingof windows. The location of two win-dows on every floor also helps inkeeping the owner’s book collection

mold-free. There is no noise frommechanical fans. The owners canenjoy their morning drink on the eastside deck, and their evening beverageon its twin on the west side. A hingedbaseboard can be opened to allowheat from the greenhouse to rise up

and warm cold feet. The Douglas Firfloors/ceilings, redwood trim, andbeams are sealed with water-basedproducts. Vegetables can be grownyear-round in the greenhouse/sunspace.

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Right: Aview of

the diningarea from

thekitchen

Right: A skylight hatch at the top of the ladder stays open

during hot days to vent warm air.Regular stairs reach all levels.

Right: A fence serves as a wind break in the vegetable garden.

Above: A translucent roof floods the ground floor with light.

Right: There are placesto sit and write or eat

on different levels.

Left: Thenorth side of the tower house.

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Cost and energy useThe entire labor and material cost of

the 2,350-square-foot tower housewas just under $200,000, or approxi-mately $84 per square foot. This fig-ure is 30% below the typical cost persquare foot of custom-built homes inthis area. The majority of the savingscame from labor costs.

The owner, who is retired, workedfull time starting a year before con-struction to gather materials, preparethe site, dig trenches, and sand beams.He kept the job site clean and orga-nized through all phases of construc-tion. When the house was finished, hecontinued to apply his incredibleenergy to dig a pond and create a per-maculture landscape around thehouse.

The monthly electric bill has variedgreatly since the house was complet-ed in 1993. It ranges 4-14 kWh a day.This high, according to the owner, isdue to visiting house guests who wereunaware of when to open and closewindows and hatches, using an elec-tric heater instead. Another factor isthe owner’s own desire for colddrinks, which motivated him to installtwo small refrigerators, one of whichended up in the 90°F temperature ofthe sun space. This unit uses nearly10 times the energy of the full-sizeSunfrost refrigerator in the kitchen.(The lesson? It takes time to developtotal energy awareness.) Even withthese transgressions, the annual utilitybill was $260 in 1994 and $438 in1995.

The propane tank was filled once inthe two-year period at a cost of $93.Propane is used only for cooking andclothes drying. The owners prefer todry their clothes in the sun space.

(Steve Heckeroth, Homestead Enterprises, P.O.Box 151, Albion, CA 95410, Phone/Fax: 707-937-0338, Website: www.renewables.com) ∆

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September/October 2000 Backwoods Home MagazineNERGY ORKSE W