Why Is There Rust on My Furnace?

Furnace Rust in Granite City, IL

Metal that is exposed to water may form rust. It’s natural. You’ve seen it tons of times. Now, though, you are starting to see rust form on your furnace. You may see rust on the components or on the cabinet of the furnace.

If this strikes you as curious, that’s understandable. Your furnace doesn’t use water to provide heat the same way your boiler or another hydraulic system would. Why is it forming rust? Most importantly, if your furnace has rust, does this indicate you have a serious problem?

Rust Is a Common Problem with Furnaces

Just because you see rust forming on your furnace doesn’t mean that you need to throw the unit away or that is going to fail on you immediately. Rust is the result of water mixing with metal and oxygen. However, if rust develops on your heat exchanger, it can weaken the unit, leading to carbon monoxide leaks.

Rust forms on your furnace because the combustion gases used interact with the metal of your furnace. If your furnace does not have a functioning ventilation system, rust occurs faster.

Typically, when we see rust in a furnace, it’s because moisture from the outside has entered the furnace through the ductwork. Or your air conditioner, which is typically positioned above the furnace, produces condensation. If the condensation pan overflows, it may drip into your furnace, creating the conditions for rust.

Don’t Let Rust Take Over

If you see a small amount of rust on an older furnace, don’t panic. It may mean that you should start to plan for a furnace replacement sometime down the road. However, if you have a newer furnace or if your furnace has a lot of rust on it, this could be an indication of a serious problem.

You will have to choose whether you want to repair or replace the unit. Our technicians at McFarland Indoor Comfort Services can help you. We are experienced in all things HVAC-related. Whether you need your furnace repaired or new one installed, AC repair or installation, or preventative maintenance, we are the licensed, bonded, and insured HVAC professionals you should call. We serve Madison and St. Clair Counties.

Indoor air quality matters. Contact us today. Let us help you with your home comfort needs.