WARWICK-Bill Makofske is a man who practices what he teaches. The Ramapo College professor of physics, environmental science and environmental studies said he has gained a good deal of knowledge through his work. "I decided when I built my house, I would use what I had learned." Makofske's home is built into a berm and well insulated to conserve energy. A pair of photovoltaic panels provides electricity, hot water is heated by the sun and a solar green house traps sunlight for heat. "I'd like to get to the point where I'm completely solar," he said n and he's getting close. The 2,400-square-foot house uses the equivalent of 150 gallons of fuel oil per year, compared to 1,500 for the average house this size, Makofske said. He figures another couple of solar panels would do it. "I'd be cheating a little," he said. "I would be getting about 110 percent of the energy I use, but Orange and Rockland won't buy extra power n they will just subtract the power you generate from your total." In order to use that extra power, Makofske said, he would use some electric heat in the winter. "I would never do that otherwise," he said. A solar system hooked to the grid will turn the meter backwards, giving the homeowner a credit on his electricity bill. But O&R will not return cash for electricity fed into the grid. If Saturday, Oct. 1, is a sunny day, visitors can see the meter running backward as well as the solar panels, the hot water and heating system based on passive solar energy and the insulation that offers the greatest savings. Makofske will open his home at 76 Drew Road in Warwick for tours Saturday at 10 a.m., 1 p.m. and 3:30 p.m. He can accommodate about 20 people per tour. Tours last about an hour and a half. E-mail Makofske at firstname.lastname@example.org for directions if you're interested. Makofske is one of about 120 New York home and business owners who are offering "Green Buildings Open Houses" through the Northeast Sustainable Energy Association. NESEA, in turn, is part of the American Solar Energy Society, which has signed up some 400 buildings for tours on Saturday. "The 2005 Green Buildings Open House offers a unique opportunity to see first-hand how clean renewable energy and green building practices are working for your neighbors," according to a press release from the organizers. "Members of the public can learn how they can reduce their energy bills and have a positive effect on some of our country's most pressing challenges." While Makofske is saving money through his energy efficiency. However, he said, he's also interested in the savings to the environment and the overall economy. There's the environmental damage caused by the drilling for, refining and use of oil, Makofske said. Then there's the fact that "our dependence on oil makes us dependent on other countries, including some we would rather not be dealing with." The pumps and transfer systems for heat and hot water, the electrical panels and the high-tech components in the house are fascinating, but Makofske said good insulation and airtight construction save the most energy. "Good insulation brought it (energy consumption) from 1300 gallons of oil to 450," he said. Solar energy reduced this by another 250. Smaller measures, such as recirculating waste heat, solar hot water and turning the heat down at night reduced the total energy use to the current 150 gallons of oil equivalent.