The bad news is that your HVAC smells. The good news is that the smell gives you an immediate warning when something is wrong with your unit. Also, the type of smell can tell you a lot of information about what might be wrong. Pass the information on to your HVAC repair company so they can solve the problem faster.
If you smell heat, burning chemicals, or hot metal, your HVAC may be suffering from a mechanical issue. Overworked motors or a malfunctioning fan can cause these electrical smells. This smell might not even indicate a real problem if your HVAC was off during the previous season. But if the smell persists, something more than just dust is burning.
However, don’t try to get to the bottom of electrical or burning smells yourself. Wiring issues can be dangerous, and DIY repairs can put your home or yourself in danger. Call in a reliable technician instead.
Rotten Egg Smells
Any time you smell rotten eggs in a house that uses natural gas, you need to be on the alert for a natural gas leak. High levels of natural gas can cause dizziness, make you pass out, or even cause death. The gas is also very flammable, and traces of natural gas in the air can ignite. If you notice this smell, power down the unit and inspect all of your natural gas ports for a leak. If you don’t feel safe checking the area, open your windows, leave the house, and call in a gas HVAC expert immediately.
When your HVAC turns on for the first time after a few months, it can kick up a wide variety of burning smells. If your air conditioning smells more like gas than like electricity or heated metal, it could still just be dust. Wait 10 or so minutes to see if the smell dies down before moving to the next step.
If your unit uses oil, be on the lookout for oily smells that signify a leak. One of the most common causes is a loose clogged valve. Repair technicians can quickly fix the issue, but it can also develop into a serious fire hazard if you don’t get it handled.
Musty and Moldy Smells
Unlike the other items on the list, mold and mildew smells might not indicate a problem with your HVAC itself. Instead, they indicate that something rotten might be in the ducts. HVACs generate a lot of moisture and pull condensation out of the air. When the moisture can’t drain away correctly, either because of a crack in the drain pan or a clog in the condensate line, it will allow mold and mildew to grow. A specialist can quickly locate and remove the source of the mold before it creates serious air quality problems in your home.
Unusual HVAC smells are often your first sign that something is wrong with your unit. Whether the smell indicates a serious malfunction, a dangerous leak, or mold growth, certified HVAC service companies should be able to clear up the cause — and the smell itself — in no time.