I’m writing this from San Francisco, where I’ve been at the West Coast Green Conference. This is the fourth year of the event–the nation’s largest green building conference and trade show focused exclusively on residential applications. It was in the Fort Mason Center, a sprawling, ex-military base with large, daylit buildings that are now used for exhibitions, and assorted meeting spaces throughout other buildings in the complex. It’s right on the water, just west of Fisherman’s Wharf–looking out on the Golden Gate Bridge.As with many conferences, there is far more going on than one can take advantage of. Between my speaking commitments–one session on innovative new green building products and another, more informal, “fireside chat” conversation with the editor of Sustainable Industries magazine–and the time I spent at our GreenBuildingAdvisor.com booth (which we powered with a bicycle generator), I didn’t have a lot of time to attend sessions. But one that I did attend focused on the importance of carrying out efficiency measures on homes before spending money on the higher-profile features like solar panels. This is a theme that I’ve included in many of these columns.The presentation was by Matt Golden, who is president of a Bay Area business, Sustainable Spaces. His company, which employees over 60 people, carries out “home performance contracting.” Their services include comprehensive energy audits and a wide range of measures to lower a home’s energy consumption and improve comfort and indoor air quality (by eliminating moisture and mold problems, for example).There are lots of home performance contracting companies around the country. Sustainable Spaces is one of the best, with its comprehensive building assessments, innovative computer modeling of improvement options, vertically integrated services (all the work is done by their well-trained crews), and strong foundation of building science.In this presentation, Matt stressed the importance of dealing with efficiency before putting money into solar and other high-profile renewable energy systems. Many homeowners come to Sustainable Spaces wanting solar water heating or solar-electric (photovoltaic) systems, but the company steers them first toward improvements that save far more money–at lower cost–through added insulation, properly sealed ducts, upgraded heating systems, and the like.By addressing efficiency first, homeowners can also end up with significantly smaller and more affordable solar energy systems–if they do install solar. This also holds true with heating and cooling systems: by reducing heating and cooling loads, these mechanical systems can be downsized, reducing costs.This is a message that Matt has helped to advance nationally in the policy arena through the nonprofit organization he co-founded this year in Washington, DC: Efficiency First. Now with over 500 members (mostly home performance contracting firms) in 44 states, Efficiency First has been working actively with legislators, including Vermont’s Representative Peter Welch, and federal agencies to push for legislation and policies that will use federal (taxpayer) funding in the most cost-effective way to address home energy use.Efficiency First–and Matt’s company–argue that home performance contracting should follow a three-phase “loading order.” The first is addressing fundamentals (insulation, air sealing, duct sealing, lighting, appliances, water conservation, plug loads, and behavior); collectively, these efforts can reduce energy use by 20-40%. Second, after reducing loads, “major systems,” including heating, cooling, ventilation, and water heating, can often be downsized. Third, renewables should be considered, including photovoltaics, solar thermal (both water heating and space heating), wind, and rainwater harvesting.When it comes to reducing carbon emissions–the ultimate goal according to climate scientists–Matt reported that appropriate efficiency measures in buildings save about $40 for every ton of carbon that is no longer emitted (in other words, we get paid for reducing emissions), while solar electric systems cost about $24 per ton of reduced carbon emission. If we do both–and he suggests that both are needed–we can use the economic savings from efficiency to pay for the economic costs of renewables. He doesn’t argue that we should skip the solar options, but that both should be part of an integrated approach to home performance contracting.Efficiency first is a compelling mantra that we should all pay heed to.I invite you to share your comments on this blog. You can also follow my musings on Twitter.