How do I figure out the cost differential between turning on an inefficient furnace and using oil-filled space heaters?
i'm interested in learning how to measure energy usage and learning how to determine the usage difference between running the furnace, which is about 50 years old and runs at about 50% efficiency and three pretty standard 7-fin oil-filled space heaters. the flat in which i live is about 800 sq.ft. and the upstairs space is about 600 sq.ft. the windows are old, but are covered with plastic shrink film for better insulation.