A sample recommendation and ranking from Microsoft Hohm. (Credit: Microsoft)

 The score is “calculated by comparing a home’s actual and potential energy efficiency,” Microsoft said in a press release. It uses home energy-efficiency models generated by the Lawrence Berkeley National Labs, which Hohm uses to create recommendations on how to cut utility bills.

Microsoft said that checking out a Hohm score will let people determine whether they are “energy misers” or “energy hogs” among more than 60 million houses in the U.S. The application generates an estimate of how energy is used in a home–heating, cooling, lighting, etc.–and offers an estimate for potential annual savings.  

After plugging in some addresses, I saw that Hohm Score tool appears to rely on real estate information and regional energy use data to generate a home profile.  

For example, I plugged in my home address and the address of my next-door neighbor–we both have older homes that are about the same size–and found that we both scored 69 out of a possible 100, which is better than the national average of 61.  

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Meanwhile, the house I grew up in gets a lower score, apparently because it is bigger than my current one and because the average energy use in that part of the country is higher.  

The idea of the application is to give people an idea of how their homes compare with others, a technique now being used by utilities that has shown to be an effective motivator.  

My initial impression is that this is a rough estimate based on house type, fuel sources, and location. For example, I’ve spent a lot of effort weatherizing my home and I have solar panels, so my overall energy bill is significantly lower than the Hohm estimate.  

In a blog, Hohm general manager Troy Batterberry said that people can get more accurate information by entering utility information.  

“You can fine-tune the accuracy of your Hohm Score and your personalized savings recommendations by creating a free Hohm account and entering some basic information about your home such as the type of appliances and systems you have. You can also update your home facts and enter your actual energy usage from your utility bills,” he noted.  

In an interview, Batterberry said that Microsoft intends to make the profiles of individual addresses more accurate by using public data or data that it can purchase, such as information on how much energy a house uses per year. It can also get information, such as which areas have natural gas service, to calculate the potential energy savings.  

Connected home platform
Longer term, Hohm can become more sophisticated by getting actual usage data from plugged-in devices, such as appliances, thermostats, or electric vehicles. Microsoft’s vision is to have a “connected home platform” where different equipment reports data to the Hohm application.  

Once home gear is connected to Hohm, the application can also control devices. For example, the heating and cooling system can be controlled through a networked thermostat. Hohm will also allow people to share recommendations on home efficiency with others.  

In Microsoft’s deal with Ford, Hohm will be used to schedule car charging, giving people the option to charge at off-peak times or to use a mobile device to start charging when they’re away from home. Microsoft said it plans on supporting whichever protocols will be used for in-home communication and send information to Hohm via the Internet.  

The connected home approach also provides one avenue for Microsoft to make money from Hohm, which will always be free to consumers, according to Batterberry. Microsoft intends to act as a broker between consumers and utilities seeking to lower peak energy usage through demand-response programs. A utility could signal to Microsoft that it needs to lower demand on the grid and Microsoft Hohm would act as the conduit to turn down energy usage in people’s homes by, for example, slowing down the charge rate on an electric vehicle.  

Microsoft also intends to provide recommendations for home efficiency jobs from Hohm, such as installing more insulation. Through those referrals, Microsoft expects to make money as well. 

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  Martin LaMonica is a senior writer for CNET’s Green Tech blog. He started at CNET News in 2002, covering IT and Web development. Before that, he was executive editor at IT publication InfoWorld. E-mail Martin.