Most days I use this space to extol the virtues of companies that bring our energy from the ground to the market, the companies that help power our country with oil and gas. These businesses are necessary, but without a doubt, the key to our energy future is to use less of it, and make what energy we do use, do more.

When we talk about saving energy, the first thought that occurs most times is using less gasoline. It is one of the most tangible energies we consume. Every day we see gas stations, hear about how high gas prices are, or actually fill up our tanks. And, frankly, vehicle fuel efficiency helps our energy saving cause immensely -- by 2025 new fuel standards will reduce American oil consumption by 2.2 million barrels per day.

But energy efficiency in our homes and buildings is just as important. The U.S. could save tens of billions of dollars every year, simply by upgrading our buildings so that they use less electricity. It is a strategy that has far reaching effects on both the economy and the environment.

The basic story
The importance of energy efficient construction and upgrades is made clear by a few simple facts brought to us by the Department of Energy:

  • The U.S. spends $400 billion annually powering its homes and commercial buildings.
  • These buildings consume 70% of all U.S. electricity, accounting for 40% of all energy use.
  • Nearly 40% of carbon dioxide emissions come from energy use in buildings.
  • Cutting energy use in U.S. buildings by even 20% can save $80 billion a year.

In an interview with the Washington Post in November, Robin Roy of the National Resources Defense Council put the long-term picture in perspective, explaining that merely bringing residential building codes up to the latest U.S. standards by 2030 would allow us to save the same amount of energy every year as eliminating 50 coal-fired power plants.

State-by-state initiatives
Across the U.S. there is patchwork-like progress being made on improving the efficiency of our infrastructure. Washington, D.C., has the most LEED certified buildings per capita, followed by Colorado, Illinois, Virginia, and Washington state. Though many of DC's LEED structures are federal buildings -- close to 30% of all LEED projects are federally owned or occupied structures -- many of them are not, and range from middle schools to private homes, to the city's baseball stadium. 

Many other states are following D.C.'s lead, and below is a snapshot of some of the different efficiency projects.

Georgia
The southern state is using energy efficiency as a way to boost employment in Atlanta, as construction jobs still lag in its capital city. Auditors from Georgia Power, a subsidiary of Southern Company (SO -0.49%), found that $18 million in improvements to the 18 buildings assessed in its initial survey could save $4.7 million per year in energy costs.

California
Long a champion of energy efficiency, California's trend continued this past November when the state passed Proposition 39, which will close a tax loophole and point half of the new funds toward energy efficiency for the next five years.

Private home builders are active in the state as well. KB Home (KBH -1.50%) has developed entire sustainable communities, boasting that many of its residences are more efficient than California's already stringent new-build standards. And KB isn't alone, Toll Brothers (TOL -1.97%) is utilizing everything from solar arrays and geothermal heating in its projects to improve efficiency.

Florida
Miami's first LEED certified hotel opened less than a year ago, and it is already watching the savings pile up. Electricity costs are down, water consumption is down, and natural gas costs have been almost halved. In a state economy dominated by tourism, energy efficient hotels should become the norm.

The future is here, almost
Despite the very solid efforts going on across the country, there are perhaps two projects that reveal the true potential of energy efficiency. One is the Bullitt Center in Seattle, and the other is Masdar City, in Abu Dhabi.

Seattle's Bullitt Center is billed as the "Greenest Commercial Building in the World," and the specs are pretty amazing. It is designed to produce as much electricity as it uses, which would make it both energy and carbon neutral. Seattle is the land of cloudy skies and persistent rainfall, but the Bullitt Center is so efficient that the 240 kilowatt solar array on its roof can generate 100% of its year round electricity.

All that rainfall will be put to work, too. Rainwater will be gathered in a 56,000 gallon underground cistern, where it will be stored until needed, treated, and used throughout the building. Overall, the Bullitt Center uses one-fifth the amount of energy as an average building its size.

Masdar City is the Bullitt Center on steroids. The Abu Dhabi project is the world's first attempt at a zero-carbon city, and serves as a very tangible example of the Middle East's burgeoning effort at growing renewable energy.

Spearheaded by the renewable energy company Masdar, Masdar City was conceived to be a clean-tech center, home to a research university and private enterprise geared toward innovating energy production, efficiency, and sustainability. Its development has seen its fair share of setbacks, financially and logistically, but it continues to move forward, implementing game-changing initiatives in technology, architecture, and urban planning that have already had significant effects on consumption patterns. For example:

  • Residents use 54% less potable water and 51% less electricity than normal. 
  • Masdar is home to a 10 MW solar plant, and 30% of domestic energy is provided by rooftop solar panels. 
  • There is up to a 20°C difference in radiant temperature on a given city street in Masdar, compared to Abu Dhabi. 

Masdar City and the Bullitt Center are two progressive efficiency projects that will eventually serve as a baseline for future development, especially as the world's population continues to grow and migrate to cities.

Foolish takeaway
So what does all of this mean for our economy and investors? Aside from the potential of investing in clean-tech companies, following this story can reveal important macroeconomic changes. Time and time again we look to housing starts as an indicator of our nation's economic health. A closer look however, at green starts and sustainable building could shine a light on a future of increasing efficiency and shrinking energy needs, both important factors for a healthy U.S. economy.