(AP) -- Enormous 18th-century houses aren't known as the most energy-efficient buildings in the world. But now the 230-year-old residence of the U.S. ambassador to Belgium has gone green, thanks in large measure to donations from private companies.
It can't have been easy: The floor space of the Louis XVI-style house is in excess of 16,000 square feet (1,500 square meters) - larger than six average American houses put together - which must have made heating it quite a project, especially as the attic was completely uninsulated.
Enter seven private companies, which chipped in various different products along with installation. The house, located in Brussels, the Belgian capital, now has window film, energy-efficient appliances, time-controlled thermostats, a touch-screen kiosk that provides real-time data on energy savings - not to mention 500 new light bulbs. The two layers of insulation that have been added to the attic are a total of 14 inches (360 millimeters) thick.
Total value of the donations - more than euro100,000 ($145,000).
The results were unveiled this week, and those involved in the project sang its praises.
"While it may look like a home rooted in history, it actually represents our energy future," said the mansion's current resident Ambassador Howard Gutman, a former Washington lawyer and fundraiser for President Obama's campaign.
Kateri Callahan, president of the Alliance to Save Energy, praised the project as an exciting demonstration of the cost savings and increased comfort that can be achieved.
"The U.S. embassy retrofit also clearly demonstrates that any existing home or building, no matter how old, can be made more energy-efficient without sacrificing any of its attractive or historic attributes and ambiance, a message that is very important for Europe, where so much of the building stock has been around for centuries," Callahan said.
And so it is that a house whose walls were going up as British Gen. Charles Cornwallis surrendered to American Gen. George Washington, ending the War of Independence, is now equipped with people sensors and web-based energy-monitoring software. It seems safe to assume that Monsieur and Madame Bartelous de Pepingham, who took out a mortgage in 1781 for construction of the house, would have been astonished.
Explore further: First of four Fukushima reactors cleared of nuclear fuel