With both air-conditioning- and heating systems, people, all too often, wait till they need them to find out they aren’t working right, or not working at all. You can avoid this by inspecting your system before the temperature drops — the sooner the better. Start by changing any dirty air filters. They make a furnace work harder and can be a fire hazard. Next, use a vacuum cleaner to remove any dust and debris from the fan area and burner chamber. With forced-air systems, check fan belt tension. It should give only about half an inch. Also check the burners to see if they work all right. Any black smudges around the access door are a telltale sign that an adjustment is needed. If you need help or have questions, call your local utility company or your neighborhood heating contractor. Then settle back and relax and let it blow, let it snow, let it blow.