Why Your Furnace Smells Sweet—and Other Odor-Related HVAC Issues

I have a lot of fun associations with wintertime from back when I was just a kid. Yessir, when I think of the winter, I think about spending weekends up in Tahoe, or drinking hot chocolate after coming from a cold day at school. Sometimes, I even think of the pine-scented air fresheners that my mom always seemed to have around our house.

One winter season here recently in Sacramento, we turned our furnace on like we always do. Except, instead of a little bit of an odor that I also remember, even from when I was kid, signaled that first start up of a furnace after summer, what we noticed was a strong sweet smell coming out of our vents. As a heating service expert, I, of course, knew right away that this was very unusual. Unlike those pine-scented air fresheners my mom used to hand up, this particular scent was not intentional.

It’s a somewhat common occurrence in my line of work, especially this time of year, to get a homeowner who notices an unusual smell. Whatever the exact smell, an unusual odor coming from your vents is usually a sign of big trouble. And that’s actually what I’d like to talk about here today: why your furnace smells sweet and other odor-related HVAC issues. We’ll go over why the furnace might be smelling, what you should do about it, and how you can potentially avoid repeat weird smell occurrences in the future. Let’s take a look!

Why Your Furnace Smells Sweet or Has Another Odor

As we’ve discussed before, your furnace and your AC are both liable to smell if something is amiss. It can be somewhat dangerous depending on what the cause is, and even more so if you think that you can get away with totally ignoring it. As a responsible homeowner, you need to find out why your furnace or AC has started to smell a certain way so that you can, in turn, know what you need to do about it (more on that in the following section).

Here are some common furnace smells—and their causes:

• A Sweet/Yeasty Smell: If your furnace smells sweet, there’s a good chance that something is very wrong. My immediate advice is to call a pro out ASAP. There’s a slim chance you’re picking up on carbon monoxide, which is very dangerous. However, there’s also a chance that what you’re smelling is mold in the vents. Either way, it’s not good and you need to contact a pro.
• A Rotten Egg Smell: This is an even more common and easy-to-identify smell than the sweet or yeasty scent. It’s definitely not pleasant, though. A rotten egg smell from your furnace might be indicative of a gas leak. This is another situation in which you need to call out an HVAC professional right away.
• A Burning Smell: The last smell is somewhat normal, at least compared to the other two more dangerous scents that we discussed above. A dusty, burning smell, especially one that doesn’t dissipate immediately after you turn off your furnace, could just mean that your air filter is clogged and what you’re smelling is dust and other debris catching fire. A trained pro can help with this too—and get you on a regular schedule for changing your HVAC filters.

What To Do When Your Furnace Smells Sweet or Stinky

You may have noticed a pattern in our answers above. That’s right, when you start to notice an odd smell coming out of your furnace, it’s time to call out a professional HVAC tech to check things out. The thing is, you just don’t want to risk some of the dangers that can be associated with smells coming out of your furnace.

This is especially true if your furnace smells sweet. Like I already noted in the last section, there’s a slim chance that you may have an issue with carbon monoxide, which is a dangerous issue for you and your family. So, it’s worth reiterating again here that if your furnace smells sweet, it’s time to call a professional to check things out ASAP.

How to Avoid a Sweet or Stinky Smelling Furnace in Winter

Now it’s time to talk about ways to prevent your furnace from giving off odd odors in the first place. There’s no real secret to this one. The way to make sure your furnace works properly, and never fills your home with stinky air, is to take your fall furnace maintenance seriously. This is the single best maintenance tip for HVAC owners.

Having a trained HVAC professional come out to your home to do regular maintenance on your furnace will help them catch any potential issues before they even start to result in an odd smell coming out of your vents. Furnace techs will be able to change your filter and also to inspect your HVAC system in a way that finds potential cracks that keep dangerous gas in. They can even do an inspection of your vents to help find mold. If there’s one thing you simply must do for your home each and every year, it’s to have a trained HVAC professional out to inspect your furnace.

I think it’s pretty safe to say that when your furnace smells sweet, there’s definitely something wrong. I think it’s also safe to say that whenever you start to smell a sweet odor from your vents, you should immediately call out an HVAC professional. With carbon monoxide on the table here, you just don’t want to take a chance.

Lucky for you, you can always call the trained HVAC techs here at Bell Brothers. We have years and years of experience working on furnaces in Sacramento homes. We have expertise you can trust, no matter what smell has started to come out of your furnace!

Contact the HVAC professionals at Bell Brothers to schedule an appointment to have your furnace and your HVAC system looked at today. We’ll offer recommendations and upgrades that are sure to increase your year-round comfort—and decrease your power bills. Contact our team today.

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Image courtesy Aaron Amat