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6 Common Heat Pump Smells Explained

By Aztil –

  • It is not normal for a home to have weird smells, especially when it has air conditioning and heating. An offensive odor that you can smell throughout the house is a sign of trouble. The good news is that these odors are quite distinctive, and so the cause behind them is relatively easy to identify. Usually, most odors will have a link with one heat pump problem or the other. The sooner you identify them and take corrective action, the lesser the chances of any disruption in your comfort. To make things easy for our clients and readers, here is a list of standard heat pump smells and their causes explained.

    Six Common Heat Pump Smells Explained

    1. Musty Or Stale Odor – When you enter a home or building that has been closed for a long time, the indoor air smells off. The best way to describe it is like that of stuffy and old air or the smell of dirty socks. The reason for this smell is mold and mildew that grow in the damp areas of the home. The most conducive environment for their growth and propagation is found in the heat pump near the evaporator coils. From here, the smell is picked up by the circulating air and dispersed throughout the house, making it stinky. 

     How To Get Rid Of It – Staying on top of the annual maintenance routine is the best way to remove the musty odor. During maintenance, the inside of the heat pump is cleaned thoroughly, which removes all mold and fungus. Once they are clean, there is no reason for the stale smell.

    2. Rotten Fish Smell – The smell of rotten fish is hard to ignore. It is so repulsive that staying indoors becomes an ordeal. Your heat pump will emanate this strong and vile odor when some component (plastic or metallic) starts overheating. Before doing anything else, switch off the heat pump to prevent further damage to the unit. Some of the reasons behind the smell could be:

    1. Problems with heat pump wiring.
    2. Overheating of plastic components or melting of rubber coating.
    3. Mechanical issues.
    4. An overheating motor.

    How To Get Rid Of It – Getting rid of the rotten fish smell is a matter of expert handling. You need an HVAC technician to eliminate this heat pump smell as it involves opening the heat pump and checking its internal parts.

    3. Rotten Egg Smells – Rotten egg smell is like the smell of sulfur. Such a smell comes from the heat pump if there is a dead animal or critter inside the ducts. Often, small animals find their way inside the ducts for warmth and protection and die inside. As their body starts rotting, it releases the offensive smell of decomposition. 

     How To Get Rid Of It – To get rid of the rotten egg smell, call your local HVAC technician. He will clean the heat pump and the ducts, if necessary. Once the body of the dead critter is removed, the smell goes away on its own.

    4. Burning Rubber Or Plastic Smell – If it smells like something is burning, it most probably is. Never ignore such smells. Often an electrical problem inside the heat pump will result in wires burning. Essentially, it is the rubber tube on the wires and the surrounding plastic that starts burning. If you fail to recognize this type of odor, the chances are your heat pump will develop a serious issue and stop working altogether. The other probability, if you are lucky, is that the circuit breaker will trip to prevent further damage.

    How To Get Rid Of It – Only an HVAC technician can help you tackle this problem. He will have to open the heat pump to determine where the electrical problem exists and take remedial action.

    5. Heat Pump Smells Like Sewer – If your heat pump produces a sewer-like smell, do remember, there is a high possibility that the circulating air has picked up the smell from elsewhere. The odor does not always initiate in the heat pump. A sewer-like smell means that somewhere in the house, the sewer line is backed up or broken.

    How To Get Rid Of It – You can eliminate the sewer smell only by clearing the backed-up line or fixing the broken pipe. However, this task can only be completed by the company that deals with sewer lines in your locality.

    6. Burning Dust Smell – A heat pump, like any other heating and cooling system, accumulates dust. Switching it on after a long interval results in a strong burning odor that typically goes away on its own within 5 or 10 minutes.

    How To Get Rid Of It – One way of ensuring that this type of odor does not come at all is by ensuring timely maintenance of the heat pump. If, for some reason, that’s not possible, at least clean the unit thoroughly. Else, allow the unit to run for, say, 10 to 15 minutes, and that should be enough time for the odor to go away. If not, call your trusted HVAC technician.


    The heat pump is not designed to produce any smells. These are actually indicators of what is happening within the heating and cooling system. Hence, it is necessary to be a little vigilant. Thankfully, most heat pump smells are not a thing of grave concern. Yes, they are disgusting and repulsive and make staying indoors an ordeal, but they don’t spell trouble for the system. The same cannot be said for the burning smells. Our only advice is to let your HVAC technician know of the odors as soon as they originate. They shall take care of the rest.

    Aztil Air Conditioningcan help the residents of South Florida find the reason behind their heat pump smells. Our trained, certified, and experienced technicians will thereafter undertake corrective measures to remove them, so you no longer have to suffer unnecessarily. You can also engage our services for HVAC installations , repairs, and maintenance. We also provide 24/7 emergency services . To book an appointment, call +1-888-729-8452 .

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