Monday, September 5, 2011

Lothlorien & the limits of sustainability

Berkeley, California

North House with solar hot water panels, viewed from South House

As the sole vegetarian house in the 1300 member Berkeley Student Cooperative (BSC), Lothlorien became the de facto eco-theme house.  Elves, as residents of Lothlorien are called, are prominent at the forefront of the green movement - just in my four years there, we passed a campus referendum to create $100,000 of funding a year for green initiatives at UC Berkeley, started a collective grocery store, and participated in tree sits.  Many residents study Conservation and Resource Studies or other green-aligned fields. 

However, our utility bills, while low, were not always at the per capita bottom among the 20 BSC co-ops.  A look at Lothlorien offers some insights on the unique challenges that co-ops face in environmental performance. 

Lothlorien facts
Type: Student housing, part of larger nonprofit (Berkeley Student Cooperative)
Built in: North House: late 1800s.  South House: early 1900s. 
Became co-op in 1975
Building type: Two 3-story walkup buildings with basements
Originally built as single family houses, expanded in mid 20th century for use as sororities and religious organization. 
Occupants: 57 (28-29 in each building)
Room mix: 15 singles (88-124 sf), 14 doubles (126-247 sf), 2 triples (233 & 450sf), 2 quads (433 & 450sf)
Restrooms: Mix of shared and private.  6 showers, 8 toilets.
Parking: 3 spaces (1 in use)

Despite being located on a steep hill with 20% grades, many elves bike.  For 57 residents, there are typically 30-40 bikes parked in and around Loth, including three shared house bikes.  Indoor storage is limited to 15 spaces in a basement, though many people prefer to park outdoors or on the street since accessing the basement requires negotiating stairs.  Theft and damage from overcrowded parking are persistent issues.  While there is a two-car garage at street level, that space is presently used as an art studio. 

Covered outdoor bike parking

With the UC Berkeley campus only three blocks away, most residents walk or bike to class.  However, 10-20% kept cars for work, school (a few were enrolled at other colleges), or weekend trips.  Cars are also used for trips to the farmers’ market.  With the one parking space reserved for loading and unloading, most residents got residential parking permits to enable them to park for more than 2 hours in the neighborhood.  There was one case of someone who had difficulty getting a permit and had to park fifteen blocks south and take a bus to her car. 

Lothlorien consists of two buildings on adjacent lots.  Each lot is roughly 6,000 square feet, with the buildings covering 1/3rd of the land.  Like the rest of the block in its fairly dense neighborhood, both buildings are 3-story wood frame houses.  A small garden is located on the sunny southwest side, with fruit trees, berry bushes, and some food crops.  It produces less than 1% of the co-op’s food.  The rest of the outdoor space, too shady for farming, is used as living space.  Livestock raising is impossible, with all outdoor space too close to neighbors or the street.  Residents interested in food production use a community garden about 15 blocks away. 
Rainwater catchment requires huge amounts of storage in the Bay Area, where winters and spring are wet and summers and fall completely dry.  Meanwhile, building codes and the challenge of training new residents and guests prevents the use of graywater.  Instead, water conservation focuses on bathrooms, which are equipped with low-flow toilets (1.6 gpf), sink aerators (0.5 gpm) and showers (1.5 gpm).  To accommodate those who like luxurious showers, two of the eight showers remain equipped with moderate-flow (2.5 gpm) heads. 

The two-building layout makes keeping warm difficult.  First, the exterior doors are opened several hundred times a day by residents traveling between common spaces.  Often doors are simply propped open. 

Second, while South House stays warm in the winter from kitchen heat, North House requires extensive heating.  Room or zone heating controllability is limited.  While residents can turn water flow to their radiator on or off, there are no intermediate settings.  Getting north facing rooms warm in the winter requires either heating the rest of the house more than necessary, or using inefficient electric space heaters.  Air conditioning is not needed or provided. 

Presently Lothlorien uses 125 kWh of electricity per day, just over 2 kWh per person.  Though North and South House have equal numbers of residents and amounts of common space, South House uses 100 kWh while North House gets by with 25 kWh.  South House has the laundry room, the server closet, and most importantly, the kitchen and its four commercial refrigerators and one commercial freezer.  Now that lighting is all compact fluorescent and computers are laptops, refrigeration accounts for the bulk of the load – around 60 kWh a day.  The fridges’ location in the hot kitchen adds to the energy use.  Also, with 80 people (residents plus boarders) using the kitchen, much energy is lost when doors are left open while searching for food.  Models with glass doors may be able to mitigate this. 
The second largest user of electricity is the hot tub.  It consumes 20 kWh a day, leading to the saying, “Having a hot tub is like having another house”. 

Solar panels were installed on the roof of South House in 2010.  Occupying 3/4 of the roof (the rest is used for solar hot water), these panels produce nearly all of the electricity needed during summer afternoon peak hours when rates are 300% higher than normal. 

Alter Systems technicians installing panels in September 2010.
Solar PV facts
Type: Grid tied
Cost: $40,000 (Equipment $26k, installation $9k, partial re-roof $5k)
Rated Output: 7.9 kW
Area: 500 sf (33 x CEEG 240W modules)
Array Tilt: 20 degrees
Array Azimuth: 130 degrees (close to due southeast)
Power generated: 3-28 kWh per day in winter, 40-55 kWh in summer
Estimated payback time: 16 years

Building Utilization
Since kitchens, bathrooms, and living spaces are shared, large co-ops like Lothlorien are able to devote around 20% of space to personal bedrooms.  In contrast, apartment buildings can only do 10-15%.  This allows for 57 residents in 26,000 square feet – one per 450 sf.  This includes several fairly generous rooms, a natural result of the idiosyncrasies of converting mansions into shared housing.  

One of the flip sides to reusing century-old houses is the need to do earthquake retrofitting.  Large common rooms on the ground floors create a vulnerable soft story condition.  North House was retrofitted in 2009 at the cost of $537,000 ($19,000 per resident), with the cost paid for by a 40-year bond backed the co-op’s properties (comparable to mortgaging the house).  This retrofit consisted of stripping the first floor and basement walls down to the studs and reinforcing them with plywood shear walls.  A new foundation and anchoring was also added – the building didn’t have much of one before, having been moved by oxen to its present location circa 1900.  Insulation was also added. 

The two house setup of Lothlorien allowed normal operations during the three months of construction, with the other building fully open.  South House retrofit is expected to cost $600,000 ($21,000 per resident) and will be similar to North House, with the addition of exterior steel moment frames around large windows. 
Though earthquake-proof, the Treehouse also needed retrofitting.  Fifteen years after its construction, the redwood it was built around had grown wider.  The tension ring clamping the treehouse to the trunk was now choking the tree.  This retrofit involved bolting wooden support brackets under the treehouse.  It cost around $700 in materials, and took five residents, some with extensive rock climbing experience and gear, a couple of weekends to complete. 

In addition to environmental and structural challenges, Lothlorien also faces accessibility challenges.  Those in wheelchairs can only enter South House and only via a back door, as the front sits 20 steps up from the street.  Once inside, there are no accessible bathrooms.  Those with invisible disabilities needing quiet also face difficulties due to thin uninsulated walls. 

Economic access also poses challenges.  Earthquake retrofitting accounts for 20% of the co-op’s budget.  Also, since Lothlorien is located in a relatively expensive neighborhood and is distant to transit, most alumni move 20 blocks southwest down the hill to the Ashby BART area after graduation. 

Looking back at my time at Loth, it’s easy to romanticize its image as one of perfection.  In actuality greater heights in co-opitecture can be achieved.  We will look at what shape that might take in a later section.

Firsthand experience, field measurement and data monitoring.


  1. Nice job on this analysis!

    From a former elf (1989) interested in ecological systems design

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