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Different HVAC Smells and What They Mean

12/27/22

HVAC smell headers

You turn your air conditioner on as the weather starts to warm up again, and you notice an unpleasant smell in your home. What’s going on?

HVAC smells are very common when turning your system on again after the winter. But it’s always best to have them checked out to ensure the smell is not being caused by a major issue. Here are some of the main causes that can be causing those odors drifting through your home.

Rotten Eggs

If you smell rotten eggs in your home and can’t find the source of the odor, it’s important to find out what’s causing it. A rotten egg smell coming from your HVAC system could be a natural gas leak.

Contact a professional immediately if you have any reason to suspect a natural gas leak in your home. It can cause an explosion or fire if it comes into contact with an ignition source, such as pilot lights or electrical switches that are on at the time of the leak.

Sewage

There are a few reasons why sewage smells could come from your HVAC system.

In most cases, it’s a clogged filter or drain line. Filters prevent pollutants from entering your home, so they cause a nasty odor when they become clogged. A blocked drain line can push odors into your home.

sewer line system

If that is not the issue, then you may have a bigger problem on your hands. There could be a fractured sewage line located near your HVAC system. A fractured sewer pipe can cause an unpleasant sewage smell to travel through your ventilation system and then spread throughout your home.

If you smell sewage in your home, it needs to be dealt with by trained HVAC professionals and plumbers. Methane is a dangerous gas, so get any smells checked out as soon as possible.

Socks

The smell of dirty socks isn’t a very pleasant one. This problem is usually caused by something in the HVAC system and can quickly spread throughout the house.

woman holding a smelly sticky sock

The main reason for this foul odor is because of mold or mildew that has been growing on your evaporator coil. The coils are located inside your HVAC unit and are responsible for cooling and heating your home.

Mustiness

Have you ever noticed a musty smell coming from your HVAC system? If so, it could signify mold growing in the ductwork and air conditioning unit.

Mold can grow anywhere that has moisture, but it thrives in areas with poor ventilation. The air conditioner pulls air from inside and pushes it out through vents throughout the home. That makes it easy for mold to grow inside the ductwork.

toy story mold meme

It’s common for homeowners to notice this problem during summer months when humidity levels are high. However, it can happen any time of year if there is excess moisture in the HVAC system or surrounding walls or floors.

The solution?

Contact your local HVAC technician and book a tune-up. They’ll check your HVAC system and clean away any mold or mildew growth.

Electrical Odors

Electrical odors can be caused by many things, but the most likely culprit is a faulty electrical component. The smell can be caused by a shortage in the system or by something that has been damaged electrically.

HVAC electrical wires
Closeup Photo on Lots of Tangled Wires. Electrical Network. Distribution of Communications.

If your HVAC system has an electrical odor and it’s not heating or cooling your home, it could be a sign of a short circuit. A short circuit can occur when wiring insulation breaks down due to age or moisture exposure, allowing wires to touch each other and creating sparks and/or smoke.

If you notice an electrical odor coming from your HVAC system, you should call an electrician immediately. The smell could mean something is wrong with your electrical system and could cause an electrical fire if not addressed.

Oil

If you can smell oil in your home, it’s not necessarily a sign of a problem.

Why?

Because the HVAC system is designed to use oil as a lubricant, the smell is normal. HVAC systems use oil as a lubricant for their moving parts — fans, compressors, and blowers — to keep them running smoothly. The oil also helps prevent corrosion on metal parts such as coils and condensers.

oil may smell inside HVAC System

But if you notice that the smell is stronger than normal, or if there are other signs of a problem with your system, you should contact an HVAC professional. You can save money by repairing minor issues before they become major.

Struggling to find the source of your HVAC smells? Contact the HVAC pros at HELP and get rid of those annoying odors.

Posted in: Heating

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