Here are the signs of furnace failure to watch out for:
Rising utility bills
As your furnace gets older, it has to work harder to maintain the same level of heating. As such, if you start to notice your heating bill going up without any other explanation, it could be a signal from your furnace that it’s just not working like it used to.
Unexplained noises are another sign your furnace is working harder than it should be. Keep an ear out for popping, hissing, rattling, banging, and anything else that suggests your furnace isn’t running quite up to par. Top common problems that may increase home inspection cost
This one is a biggie. Your home’s furnace has one important job: to heat your home. So if it’s not doing that job well, it may need a replacement part—or it may just be at the end of its life. Aside from just being cold in your home, air that alternates in temperature from room to room is also a sign that your furnace isn’t working properly.
It’s very common for furnaces to need at least a couple of repairs before they need to be completely replaced. If you notice however that you’re having to call your heating and cooling professional out more often than you used to, it’s probably time to look into buying a new system.
A yellow burner flame
A healthy furnace always has a blue furnace flame. If it’s yellow, that’s your cue that something is off. It might be that dirt, debris, or dust are gathering up heavily around the flame, or that there’s excess moisture or draftiness. It can also be a sign that your furnace is creating carbon monoxide (which is definitely not good). Sometimes the problems causing a yellow flame are not due to the furnace itself, but it’s still always smart to have someone come out and look at it right away.
Furnaces work hard, and they’re not meant to last more than a couple of decades. If you know your furnace is getting up there in years then have someone come evaluate it, even if you haven’t noticed any other signs that it may be due for a replacement.