And the couple also hasn't paid for heat or air conditioning in six years.
The Lefevres' Kingston, N.H., home is among the most energy-efficient in the country. And soon that technology will be coming to Methuen.
Bob Lefevre is the man behind this thermal mass technology, and creator of a home that doesn't need any traditional heat source and doesn't emit any greenhouse gases that contribute to global warming.
"I've always been concerned about the environment," Lefevre said. "This was our way of doing something about it. If we change our mind-set, (the country) has no energy shortage. Sunlight operates the entire heating and cooling system."
The design uses energy from the sun for heating all winter and cooling all summer for the amount of energy it takes to run two 100-watt light bulbs. When the home was built in 2001, it was the largest home with a solar energy system that had no backup heating.
Lefevre, president of R. Philips Technological, which produces aviation electronics, is designing plans to bring similar homes to Methuen. His stepson, Robert Pellegrino of Pellegrino Construction in Salem, N.H., a general contractor, will build the homes.
Pellegrino has purchased land off Route 110 in Methuen to build 31 new homes. Seventeen traditional wood-frame houses are already under construction as part of the first phase. Part of the land also has been sold to another developer.
In a year, Pellegrino plans to build six to eight "green" homes using his stepfather's design.
"We want to give people the choice for an energy-efficient, standard home," Pellegrino said.
The 4,300-square-foot house in Kingston uses a series of radiant floor pipes to circulate warm water throughout the house, generating heat. The Lefevres moved to New Hampshire from Methuen.
The basis for the energy efficiency is the house itself. It has walls that are 14 inches thick and made from steel-reinforced, concrete-filled, Styrofoam-sided blocks fitted together like LEGOs. The walls retain heat to stay a constant 55 degrees all year, meaning it will take less energy to add heat to the home.
In the basement is a thermal mass of concrete, sand and stone threaded with pipes that carry water along the floor. The water is heated in winter when the sun's energy is stored in the stone and cooled in summer when the stone has been shaded and cooled.