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6 Common Heat Pump Smells Explained

By Aztil –

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  • 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.

    Takeaway

    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 +561-559-2205 .

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I've been using Aztil for over 10 years. Always prompt, polite, knowledgeable, and professional. Today (Memorial Day), my AC went out. Within 2 hours, Albert was at my house and fixed the issue quickly. I would recommend Aztil to anyone based on my own personal experience with them.

This is my second review on Aztil but I felt I must say something about the outstanding service I received from Tino today, 9/16/25.
Tino came out for a regular scheduled maintenance. While here he answered some concerns I had and helped me resolve them quickly. Not only is he knowledgeable but he also took the time to explain the 'why' to me. He didnt try to upsell (which I appreciate) and even told me what I could hold off on until another time. I appreciate the time he spent educating me so that I now have a better understanding of my AC unit. I give Tino 5 stars b4cause he earned them. Thankyou Aztil for employing professionals who know their 'stuff'.
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Michael was very professional and curiously
I had Michael king as my technician.
He is a professional he represented the company very well. Very knowledgeable about the job . Patient in explaining his workload. He is a great addition to any business and aztil air have a treasure in their hand . I encourage you the experience.
Antonio was the best!
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Niko was great.
Niko was very patient and professional. Looking forward to cleaning this system.
He was great!
Niko came out promptly on a Saturday and fixed my problem easily. Great customer service
Response from the owner:Bernice Demanche, I'm glad to hear that Dana provided prompt service and fixed the issue easily. Excellent customer service can really make a difference in situations like these.
Niko was great- very informative
Niko very nice and did a good job explaining.
Niko, great service! Thank you!
Niko was personable and knowledgeable
Antonio was great and he was personable and I really do like him the next time that I have a visit from you guys it will be from him and I almost decided not to use you guys no more because of the other two gentlemen that came they were young boys, and they did not do things properly, but Antonio was very very good and I really liked himHe was very professional so thank you very much for letting Antonio come and giving yourself a second chance have a blessed day.
Nicholas (I think that’s his name) was very thorough and knowledgeable. I’m going to take his recommendation for a UV light. Please send him back to install when I order it. He furthers my trust in Aztil.
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Very happy with the service provided by Niko
Technician Lazaro Powery arrived much sooner than I expected. He looked professional, and his behavior matched his appearance. I really enjoyed our brief personal chat. I always ask people I deal with if their company treats its employees well, as it matters to me. I was happy to hear that he enjoys his employment with Aztil.

His professionalism and attitude well matched his positive comments. I'm not surprised as I find Aztil to be excellent people to deal with in all requests and transactions. Lazaro sets a good example for Aztil. Thanks for sending him. When he asked, I signed another one-year service contract
I had 3 terrific technicians Paul Gross who found the problem fixed it but also found a leak so I had 2 technicians Jordan and Hero come and do the duct work I was so impressed by all 3 of them their knowledge professional and the enjoyment in doing the work for their clients I give all 3 of 10 gold stars😀
AZTIL is a real COOL company and Jackie my rep @Aztil responds ASAP when I get HOT on the phone. Seriously Jackie’s the nicest person. I don’t want to leave anyone out but Juan the technician goes above and beyond trying to solve my HVAC problems.
Alex was very thorough and knowledgeable.
Tino was professional and friendly. Thank you for a great service over the years.
I have used aztill air conditioning service for over 15 years. They have always been prompt and have always done a great job. I recently would like to praise Dana who came to my home today and his boss Jack for the great price. My wife and I feel blessed to have found them. They have been reasonable in their prices and the technician are right on point. Thank you Aztill Air. 😁😃
This was my first experience with Aztil as a new homeowner. I purchased a service agreement which I thought was reasonably priced. My first scheduled maintenance was this past week by Michael King .He was extremely professional, knowledgeable and very kind in explaining everything I needed to know. He made a great suggestion in which I followed through with. He’s an asset to this very professional company. Thank you Aztil and Jonathan for a job well done!
Mike came by for an A/C maintenance check up. He came on time and was very friendly and professional.
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Excellent service very knowledgeable Niko send him hereafter
Tino was exceptional in sevicing both of my AC its. I renewed my contract with Aztil and I look forward in having Tino service me again Thanks for great service
I had to have my air conditioning HVAC system replaced. I bought RHEEMS from them nine years ago or just shy of nine years ago and I had to have the whole thing replaced. It had a leak. The pressure was down 3 pounds and to pay $475 only because I had a contract with them otherwise it would’ve been 675 to check for the leak.. I decided to replace it cause I knew it was around the corner anyhow. They installed it the next day I couldn’t have been more pleased. It was effortless. It took them a while because we had some rain on and off and they couldn’t be on the roof, but they came at 9:30 and they left at 3 o’clock. I thought they did very well. They left my house clean as a button just exactly the way they found it. They were very polite and did everything that they were supposed to do in a very neat and tidy and timely manner.
Jorge and David were the installers today. They were timely, professional, mannerly, exceptionally clean and efficient. And Sabrina in their office went beyond in responding as the cost of new units today is sticker shock!
Nico is absolutely amazing! Very informative and an excellent technician! This is the second time we’ve had him and he’s great
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After 40 hours without A/C in August we were saved by Rafael. He was polite, professional and courteous. He is an asset to the company. On another note, the scheduling system used for after hours is quite poor and needs to be looked into. Thank goodness Jackie called us and attempted to remedy the situation.
Naraldo Bunsie did an excellent job installing my new Trane A/C! Thanks !
Michael was very knowledgeable and efficient in providing service for us today. We’d love for him to come again
Your service techs and general service has improved since the corporate take over. Raphael Curci was efficient and kept us u[p to date on the progress of the installation. The person I'd like to call out as exemplary was Nico who guided us through the process and went out of his way to help us through this time. Ultimately the air handler was faulty and it took several visits to repair it. Meanwhile the handler leaked water all over the garage ceiling ruining it and causing damage to my model trains beneath. In addition the last tech broke my cable power supply which he had no business touching. I had to call Xfinity to come as an emergency for which they charged me $150.00. I will also be sending Aztil a bill for the repair of my ceiling and any damage done to my model trains.
Dana just finished a service call. He was very professional and explained to me what he was doing and gave me tips for the future. I have been an Aztil customer for many years and people like Dana keep me coming back.
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Michael was efficient and thorough. I am very pleased with this service.
Response from the owner:Thank you
Juan was fantastic!
Michael was great, he called in advance arrived on time, very professional and knowledgeable, and got the job done in a timely manner, highly recommend.
Michael provided excellent service on unclogging our drain line and explaining what options we have to prevent it getting clogged in the future.
Naraldo was was a competent and efficient skilled worker..
Doesn't talk much but gets the job done quickly.

Replaced and rewired our new water heater in a very short time.

Left everything clean and Sparkling..

Would have him return anytime for the next project that might pop-up.
Response from the owner:Hi Erlene, thank you for your kind words! We're so glad to hear that Rafael did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Dana Dussault, the technician that came to fix my AC and installed a new compressor was so efficient and courteous and is an asset to Aztil. I was very happy with the work.
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