Winter can come on like a lion, with temperature dropping below freezing within a matter of days. One of the worst things to have happen on the first cold, winter day is to find that your heat does not work. To prevent such an issue, try turning your heating system on at least once in the fall before temperatures drop so low that you really need heat. As the system runs, keep an eye out for these signs that indicate your furnace needs heating repair services before winter.

1. Any Concerning Odor

The only odor that should be considered normal when coming from your heating system is that of stale dust. If the air has any metallic, burning, or rotten quality to it, then you absolutely need to call a heating repair person. Metallic odors may mean that certain components are rubbing together inside your furnace, or that there is an electrical problem. A burning smell may indicate that the furnace burner is dirty or overheating, and the smell of rotten eggs indicates a gas leak. (If you suspect a gas leak, leave your home and call the gas company -- ASAP!)

2. Rattling Noises

It's normal for some furnaces to click as they turn on. But if the furnace rattles as air blows out of the vents, this is a whole other matter. The rattling usually means that the blower motor has lost a bolt or screw. A larger component may be about to snap off if you keep operating the furnace. Most blower motor issues are easy to fix when you catch them early, but if you wait, you may have a bigger problem to solve.

3. Cold Air

Make sure you pay attention to the temperature of the air that is blowing out when you turn the furnace on. It's not unusual for a furnace to keep blowing air, even if it's not heating the air. If the air coming out does not get warm within a few minutes, you may have anything from a broken burner to a busted thermocouple.

4. Short Cycles

Pay attention to how long the furnace runs before turning itself off. It should run for a few minutes, and then turn off until the room temperature drops below the thermostat setting again. If the furnace is turning on and off and on and off in short succession, this means something is amiss. You may have a blocked duct or an electrical issue.