Microsoft Web site aims to make your house a Hohm

(AP) -- Microsoft Corp. is slowly beefing up a Web site aimed at helping people monitor their home energy use and pinpoint ways to cut costs.

The site, called Microsoft Hohm, launched last summer. People can enter details about their home, such as when it was built and what kind of heating system and thermostat it has.

Hohm can also be hooked up to users' utility accounts, though so far this only works in some areas of Washington, California and the Midwest. Microsoft models year-round weather conditions and other factors using a mix of its own software and research from the U.S. Department of Energy and the Lawrence Berkeley National Laboratory to come up with a picture of how much energy a home uses. The more data the system has, the more accurate its estimates would be for how much someone would save by installing a programmable thermostat, for example.

Starting Wednesday, Microsoft is adding real estate data to its calculations and assigning a Hohm score to most houses in the U.S., so people can compare their home to their neighbors' or scout one they're thinking of buying. The scale goes from one (think of running the heat full blast with the windows open, for starters) to 100 (energy-efficient sainthood ).

For now, Hohm seems of limited use. After all, there are countless Web sites that tell me to replace my incandescent bulbs, wrap a special blanket around my hot water heater and insulate the attic.

The idea gets more interesting when all the appliances and outlets in the house can talk to the Internet and feed data into a site like Hohm. Troy Batterberry, who leads the Hohm team at Microsoft, says people could then use the site to see their energy costs broken down in much finer detail.

Batterberry also hopes Hohm will be part of a "smart grid." Microsoft could feed aggregated data to power companies to help them understand and predict usage, which would help control costs. People could also use Hohm to set up appliances to run when energy prices are lower.

Microsoft hopes Hohm will eventually make money from targeted ads on the site - local contractors who install insulation, maybe - and by charging utilities for data about customers' energy usage.

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