Energy efficiency is a very noble and seemingly mutually beneficial goal: It's environmentally conscious while – in the long run – also being financially advantageous for homeowners and businesses. President Barack Obama has said he hopes to double the efficiency of the United States' power consumption by 2030. But how much do we really know about this subject? Is it more eco-friendly to insulate houses to prevent heating leaks, or to put more fuel-efficient cars on the road? Which option is cheaper? Which sees the greater return? The answers to these questions are still hazy, and may be rife with myth and misinformation.

As Brad Plumer, an energy and environmental reporter with the Washington Post, writes, the confusion over these questions is what has motivated a joint MIT-University of California, Berkeley think tank called E2e, which aims to scientifically examine the cost-benefit ratio of energy efficiency.

A 2009 study showed that energy efficient homes and office buildings that have had leaky ducts sealed or older appliances upgraded could save $680 billion in energy costs over a decade and have the environmental impact of taking all of the country's cars off the road. But a more careful look at this too-good-to-be-true data revealed a more complex situation that E2e hopes to better analyze.

"[These] studies can't account for the behavioral changes you might see in responses to efficiency improvements," said Christopher Knittel, one of the project's co-directors. In other words, making utilities cheaper may actually cause energy use to increase, rather than decrease.

While it's not yet known where the biggest returns in green power lie, what is clear is that the battle for energy efficiency starts in the house. Maryland homeowners should meet with home inspection contractors to check their property and determine where the greatest return in power reduction may be.