Even before home energy costs began spiking this winter, David Moon had faced eye-popping bills to keep his Westchester, New York, house warm as his monthly heating oil tab approached $1,000. “It was a huge sticker shock for me,” says Moon, who had bought his 4,400-square-foot home in 2019 after relocating from Nevada. This winter, he didn’t sweat his energy use, even though oil prices hit a seven-year high in early February and have now climbed above $100 a barrel following Russia’s invasion of Ukraine. That’s because in August, Moon completed a project that experts say is one of the most effective—if mundane—ways to lower high energy costs and cut a home’s greenhouse-gas emissions: plugging holes and insulating walls and attics. He also replaced a boiler with four highly efficient electric heat pumps that extract warmth from […]