A furnace is a large appliance that uses combustion to generate heat for your home. This device helps warm the home by burning fuel and represents a major component of the central heating system. While most U.S. families heat their homes using furnaces, one downside is that these devices are also prone to rust. Fortunately, intervention from trained experts can stop rust from having a detrimental impact on your property. A look at the best ways to handle rust on the furnace offers insight into how to protect your heating system.
What Is Rust?
Rust is a reddish-brown substance formed when iron reacts with oxygen and water. The process that creates rust is called oxidation, and the scientific name for rust is iron oxide. Rusting can occur when objects made of iron, steel, or ferrous metals experience long-term exposure to water vapor or moisture. The formation of rust is one of the most recognizable forms of corrosion in the world.
What Causes Rust on a Furnace?
Most furnaces are located in enclosed spaces such as utility closets or basements. Rust can occur as a result of moisture in this compact space or as a side effect of the furnace’s operational process. The most common direct causes of rust include high humidity, poor ventilation, water leaks, furnace exhaust problems, or a badly aging unit.
High Humidity
Humidity refers to the amount of water vapor or moisture in the air. Upon turning on the furnace, the heat can cause this water vapor to condense. The presence of moisture on your metal furnace can break down the protective coating. This moisture will then accelerate the natural oxidation process and lead to corrosion and rust.
Improper Ventilation
Poor ventilation can also cause rust. Even if your furnace does not use water to create heat, it can still come in contact with moisture through your return air ducts. If the home is overly humid, water vapor inside the ventilation system can reach the furnace and catalyze the chemical reaction with metal that results in rust. Furthermore, this problem can worsen if your ducts have tears or leaks that drawn in even more humid air from various parts of the house. Finally, inadequate ventilation within the furnace storage room itself can increase the likelihood of rust.
Leaking Equipment
Another possible cause of rust is a water leak from a piece of equipment directly connected to your furnace. In many home HVAC systems, the air conditioning unit sits above the furnace so that both units can use the blower. Central air conditioners may also integrate into the furnace ductwork. During normal operation, air conditioners produce water condensation as part of the cooling process. This moisture drains away into a condensate pan or tray. But if the condensate drain line becomes defective or clogged, the condensate pan can overflow. This causes water to trickle onto the furnace and can quickly result in rust.
Furnace Exhaust Issues
If the exhaust is faulty, the furnace’s normal heat generation process can lead to rust. Within a gas furnace, the combustion gas in the heat exchanger turns into a liquid vapor as it cools down in the heating cycle. Without a functioning exhaust to release this rapidly cooling air from the furnace interior, rust can quickly develop on the metal. Rust can develop on the heat exchanger itself as well as any other interior metal parts.
Insufficient Maintenance
Insufficient maintenance can exacerbate rust problems by allowing dirt, salt, debris, and other contaminants to accumulate on the metal components of the furnace. This buildup worsens the effects of corrosion and can stop your furnace from functioning properly when you need it most. According to the Department of Energy, HVAC units that do not receive consistent maintenance can lose an average of 5% efficiency per year. Regular inspections can lower the risk of rust and keep the unit running smoothly.
Old Age
Older units can show signs of corrosion due to extensive exposure to combustion. The years of combustion exposure also means that older units are more likely to show rust on the heat exchanger. If your unit is more than 15 years old, an HVAC technician can determine whether the heat exchanger is worth rehabilitating or if it is more practical to simply replace the unit.
What Are the Risks of a Rusty Furnace?
Rust can have a negative impact on your property. Serious problems associated with rust include clogged burner jets, fuel supply line issues, and even combustion gas safety issues.
Clogged Burner Jets
The presence of rust can speed up the degradation of your heating system. This means that the burner jets will become clogged with corrosive oxide and fail to perform correctly. The burner jets may also require more fuel to sufficiently heat the home, thereby resulting in higher heating bills.
Fuel Supply Line Problems
Rust can also damage or block the fuel supply lines. Since the supply lines are essential conduits during combustion, this blockage can create fuel backups. Such backups are dangerous because the pressure can eventually cause explosions or house fires.
Heat Exchanger Safety Issues
The presence of rust on your heat exchanger can create a vicious cycle that stops your furnace from performing correctly. Poor heat exchanger performance can also lead to carbon monoxide leaks due to incomplete combustion. Carbon monoxide is an odorless gas that is toxic to humans. In high concentrations, carbon monoxide is lethal. It is important to reach out to a professional right away if you suspect rust in your furnace.
What Can I Do About Rust on My Furnace?
As you can see, rust is more than just unsightly discoloration of your system. A furnace overrun with rust and corrosion can pose a threat to the safety of your household. Fortunately, HVAC professionals can correct rust issues with maintenance, repairs, and unit replacements if necessary.
Routine Furnace Maintenance
Scheduling routine furnace maintenance allows an HVAC technician to perform a thorough inspection of your system. During this checkup, the technician may remove any rust present as well as clean or lubricate the mechanical parts. If detected early enough, the technician may also be able to replace internal parts like heat exchangers if they have rusted beyond repair. Finally, a technician can apply protective coating to reduce future rusting. In addition to regular maintenance, you can also schedule an annual tune-up to test your entire heating system.
Repair and Replacement
If you have neglected maintenance in the past, the technician may need to conduct more extensive repairs. But if the appliance is older and highly corroded, technician can also help calculate whether it is more cost-effective to replace the unit. Signs that you may need to replace the unit include the following:
- Unusual sounds or smells during operation
- Exorbitant heating bills
- High condensation on unit or in the utility room
- Constant need for repairs
- Excessive circulation of dust when using the unit
Finally, an HVAC company can also help you determine the best way to upgrade the furnace. For example, selecting a newer Energy Star furnace may improve heating performance by 97%. This can ensure the best return on investment and create a more comfortable environment within the home.
Get Help Today
Rust on your furnace requires prompt action. Fortunately, the experts can help. Davis & Green provides furnace repair and replacement services for homes in Richmond, VA and surrounding areas. We work with both gas and electric furnaces and offer routine maintenance as well as tune-ups. In addition, we can also help with heat pumps, boilers, and generators. Never let rust take its toll. Contact Davis & Green today for all furnace needs.
