A doctor can tell if you're sick by taking your temperature.

EcoFactor is concocting software that can do the same for your house.

The startup -- which has invented a home energy management system that gets sold through utilities and communications carriers -- has obtained a patent for calculating the thermal mass of a building. Software derived from the patent crunches historical weather data, data on how much you use your heater and air conditioner, and other factors to diagnose your home and pinpoint any problems.

In a test case in Fort Worth, Texas, for instance, a consumer had purchased an ultra-high efficiency air conditioning system but was still experiencing extraordinarily high bills. The software helped find the problem: crushed ducts and a dryer duct that was venting into the home's air handler.

"He was losing money every time he turned on the air conditioner," said co-founder and senior vice president of products Scott Hublou.

In another house, the software detected a clogged furnace filter that boosted HVAC consumption by 8 percent to 9 percent.

The company will use the technology to optimize its own services. In a nutshell, EcoFactor links its software-as-a-service to your thermostat and then dynamically adjusts the temperature all day, within comfort parameters set by the homeowner, to save energy. Oncor is currently reselling the service to its customer base in the Dallas/Ft. Worth area. EcoFactor claims the system can curb energy consumption by 25 percent to 30 percent; it is particularly effective in muggy areas like the Southeast where air conditioning is a way of life.

But the patent could also conceivably be used to analyze small commercial buildings. Another idea: using the software as a prelude to a full-blown energy audit and retrofit.

"You could quantify the actual savings," said John Steinberg, CEO and the other co-founder. "It is less labor-intensive than an audit."

EcoFactor has an number of other patent applications winding their way through the U.S. Patent and Trademark Office, so expect to see more of these. Disclosure: although many reporters and analysts disdain patents and whine that patents, particularly software patents, stifle innovation, I believe intellectual property remains the bedrock of Silicon Valley.

Patents are "something that we think have absolutely helped us on the funding side," said Steinberg. "I don't think there is any question that it is helpful to have a deep and wide patent portfolio."