Set your thermostat as low as is comfortable in the winter and as high as is comfortable in the summer.
Clean or replace filters on furnaces once a month or as needed.
Clean warm-air registers, baseboard heaters, and radiators as needed; make sure they’re not blocked by furniture, carpeting, or drapes.
Bleed trapped air from hot-water radiators once or twice a season; if in doubt about how to perform this task, call a professional.
Place heat-resistant radiator reflectors between exterior walls and the radiators.
Turn off kitchen, bath, and other exhaust fans within 20 minutes after you are done cooking or bathing; when replacing exhaust fans, consider installing high-efficiency, low-noise models. During the heating season, keep the draperies and shades on your southfacing windows open during the day to allow the sunlight to enter your home and closed at night to reduce the chill you may feel from cold windows.
During the cooling season, keep the window coverings closed during the day to prevent solar gain.