Modern gas furnaces are a highly safe and efficient way to heat your home. However, like any natural gas appliance, it is extremely important to make sure your furnace is venting properly to ensure that harmful fumes and carbon monoxide aren't backing up into your home. Here are three signs that your furnace may not be venting properly and it's time to have it inspected.

Yellow Burner Flame

If you know what to look for, your burner flame can tell you a lot about the balance of fuel and oxygen that your furnace is receiving. When your furnace is operating at maximum efficiency, the burner flame will be blue and burn steadily. A burner flame that is yellow or flickering could indicate that fuel isn't burning off completely, which may be due to a furnace ventilation problem.

Rusted Flue

Your furnace flue is the most important component for venting your gas furnace properly. Roof leaks and other continuous sources of moisture can sometimes cause the flue to rust. If your flue appears rusty, you should take it as a sign that repairs will be needed soon. 

If the flue rusts through, fumes may be able to escape into your home before they are expelled outside through the flue. Inspect the flue for signs of rust every few months, and stop using your furnace until you schedule repairs if you notice any holes in the flue.

Rotten Egg Smell

One of the reasons that carbon monoxide in the home is so dangerous is because it is normally undetectable. This colorless, odorless gas can cause headaches, nausea, confusion, and eventually unconsciousness and death if undetected. Every homeowner with a gas furnace should invest in carbon monoxide detectors, but there is another way to potentially detect CO leaks that you should be aware of.

For your safety, natural gas that is delivered to your home is mixed with an additive called mercaptan. Mercaptan has a very distinct odor that many people compare to rotten eggs. If you notice this smell when running your furnace, stop operating it immediately, ventilate your home, and relocate outdoors until you can have your system inspected.

Proper ventilation is essential for safe operation of any modern gas furnace. Keep an eye out for these signs of poor ventilation so you can take the necessary steps to keep your home safe if you are ever faced with this problem. If you suspect you have an issue, speak with professionals who provide heating repair services.