Just like your air conditioner, your forced-air heating system has a filter that prevents blockages by keeping out dirt and dust to prevent blockages. If that filter—located in the furnace or at a return register—gets clogged, the unit will operate inefficiently and will cost you more money. One recent study indicated that a severely clogged filter (a filter with only 20 percent capacity remaining) reduced heating efficiency by 25 percent! And it’s so easy to avoid this problem that it’s a joke. (more…)