Saving dollars, slashing emissions: Home energy audits offer twofold and timely results

Photo Source 2007 Buildings Energy Data Book, Table 4.2.1

Messages to reduce home energy use and carbon dioxide (CO2) emissions inundate homeowners every day. Conservation makes sense for the wallet and preserving resources, but there is another reason to consider reducing energy use. Next year, PG&E will install smart electric and gas meters that wirelessly report usage by time of day instead of the month’s total power consumption.

With smart meters come new pricing plans that offer incentives for customers to use less energy during peak hours. By cutting and controlling energy use, you may be able to take advantage of lower pricing.

Recently, Mountain View-based Ennovationz conducted an energy audit of my home. Its findings outlined where electric and gas energy was expended and how I could trim consumption. Typically, households can save the most energy, decrease CO2 emissions and get the best payback through energy-efficiency improvements. If you want to go further and create a carbon-neutral home, you’ll also need to invest in renewable energy, such as photovoltaic solar.


The gas and electric consumption of the typical Los Altos home costs homeowners more than $4,000 annually and produces more than 8.8 tons of CO2. Multiply that by the approximately 9,200 households, and residents pay more than $37 million and produce 81,000 tons of CO2. This does not include the additional CO2 we create daily through activities such as car trips, air travel and waste processing. It makes sense to decrease electricity and natural gas use.

PG&E has pricing tiers, so the more electricity or gas a household uses, the higher the rate per unit of energy. As you cut energy use, each kilowatt or therm you save reduces the most expensive top-tier costs, approximately $0.41/kwh for electricity and $1.28/therm for gas. For assistance on your quest to reduce energy, I recommend a home energy audit to determine your home’s specific situation.

Studies indicate that homeowners who can view their electricity use in near real time throughout the day tend to reduce it by 10 percent to 20 percent. Greenbox, for example, offers a Web-based solution that enables households to track, understand and manage their home energy consumption and environmental footprint.

Reducing base load

The base load is the electricity your house consumes 24 hours a day and includes devices that run constantly, such as power supplies, TVs in standby mode, networking equipment, clocks and computers. Ennovationz found the base load on my home was 240 watts, or approximately 16 percent of the total electric use.

Examine your house to determine if you can reduce its base load. For example, a 60-watt bulb continually burning uses more than 500 kwh/year – roughly $126 annually. There are smart powerstrips that can automatically turn off printers and other peripherals when you shut down the computer.

Increasing efficiency

The first $5,000 to $15,000 you spend on energy-efficient improvements reduces high-priced energy tier use and provides the biggest payback. Some sample efficiency improvements in priority of benefit include:

• Seal, insulate and clean heating/cooling ducts. PG&E estimates that 10 percent to 30 percent of a home’s heated or cooled air is lost through leaky ducts. PG&E now has a duct rebate program up to $400.

• Use R-11 insulation in walls, R-30 in ceilings and R-19 under floors. The Department of Energy estimates that only 20 percent of homes built before 1980 are well insulated.

• Caulk and weatherstrip around doors, windows and other openings. This is relatively inexpensive and has one of highest returns.

The second part of this article will be published in the Town Crier’s Nov. 18 Go Green Los Altos section.

Ennovationz has compiled the following information on the energy consumption in the average Los Altos home of 2,747 square feet

• Air conditioning – 32 percent.

• Swimming pool – 42 percent.

• Average daily electricity consumption – 36 kwh/day.

• Average total electricity consumption – 13,034 kwh/year; $3,128 ($0.24/kwh); 6,821 lbs. CO2.

• Average total gas consumption – 811 therms/year; $916 ($1.13/therm); 10,900 lbs. CO2.

• Average total household PG&E bill – $4,044; total CO2 generated – 17,721 lbs., or 8.8 tons.

For more information, visit



For more information, call 625-0868 or visit the U.S. Department of Energy Web site at





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