Despite two weeks of clear skies and sunshine, we bought a space heater this past weekend. Last week's temperatures were unseasonably cold. Lawns were often frost covered in the early morning. Daily temperatures were warmer this week but we saw ice patches where overnight sprinklers had watered sidewalks. We could have taken a cue from the Carter administration and bundled up in sweaters and thick socks (which we did for one night), but a space heater seemed like a reasonable purchase. If we were owners instead of renters, we could consider installing solar panels or other renewable energy technology. Fulton and Oregon Solar roof panels were recently installed on the southside of a house in the Le Conte neighborhood. Also, I have noticed that many apartment buildings have solar roof panels. I intend to map these buildings (please send the addresses of the ones you find - you can leave the information as a comment to this post). The City of Berkeley has an Energy and Sustainable Development Office and its website highlights four local exemplars of green development: Urban Ore Eco Park, Shorebird Nature Center, Berkeley EcoHouse (read about the house courtesy of the Ecology Center), and Civic Center. Electrical energy is being greened in many ways, one of which is featured in today's issue of the Oakland Tribune. The paper reports that Lake Merritt's necklace of light bulbs has been replaced with energy-saving light bulbs. The statistics: 4,000 bulbs, 25,000-hour life vs. 2,000 hours for traditional bulbs, and $9000 annual energy savings. Like the City of Oakland, renters (and house owners) can switch to energy-saving light bulbs and appliances. Other steps include insulating doors and windows. Trees and shrubs - with appropriate species and arrangement - can improve the energy efficiency of buildings. Shade trees are especially important in alleviating the urban heat island effect. In my case, the quince tree outside one of the south-facing windows loses most of its leaves in the winter, allowing the sun to warm the apartment. In the spring and summer, full of leaves, the tree filters the sun, keeping the apartment cool. The second south-facing window is not protected by any vegetation, and as a result, that part of the apartment can be very warm in the spring and summer.