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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.

    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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Jordan & Herolson did a great job cleaning my ductwork. They arrived on time, were very nice, polite & efficient. Jordan explained everything clearly. They cleaned up thoroughly when they were done. The popcorn from my ceilings was everywhere, but they took care of it. Five stars.
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Niko is always a competent , pleasant professional who assists me with my air conditioning units.

AZTIL responds to my calls in a timely manner.
Response from the owner:Hi Debra, thank you for your kind words! We're so glad to hear that Niko did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Jordan an hero where effective angel. They explained evdrthing and extremely pleasant
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Tino was friendly, professional and very helpful
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Dana was great!! Suggested a cut off switch to stop the water backup
Installed it right away
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Dana came today, diagnosed my A/C problem and took care of right away.
Terrific service! Thank you, Dana!
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Best workers, Jordan,and Hero.
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Thanks to Aztil AC! One of our A/C units broke down unexpectedly, and Anthony got Lazaro out to us right away the next morning. Lazaro was excellent and he found the problem with our unit very quickly. We really appreciate their quick action and professional expertise. Outstanding service from start to finish!
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Just has Dana come as soon as Aztil can get there team there for our family. Dana was friendly, professional and knew his stuff.
Response from the owner:Hi Justin, thank you for your kind words! We're so glad to hear that Dana did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
The AC maintenance service was excellent. Niko Garza was professional, helpful, kind, and was instrumental in arranging for the next Senior Technician to solve the AC problem that I am having. That service will be sometime today. He also recommended the dryer vent cleaning and the in-line AC cleaning, of which I scheduled for Monday and paid today. My husband has been very ill for the past 4 years and in the hospital right now. Aztil has arranged the services, after Niko explained the situation, so that they will be completed before he comes home because a patient on oxygen and a feeding tube cannot be without power to the whole house, even a short shut down would endanger him. Thank you Niko!

Technician Rick Cochran did an excellent job replacing the AC breaker and ensuring that everything was in correct working condition. I really appreciated his kindness and professional demeanor. Thank you Rick!

Today Technician Alex Molina completed the services (dryer lint trap cleaning and inline air handler cleaning). Once again, I was fortunate to have a professional, gracious, and thoughtful person come to my house to perform the services. Thank you so much Alex!

June 2 2025 Thank you Cody! It is a relief to finally have the A/C back to what it should be. The replacement of the coil is probably what was needed a month ago. Rather than dwell on what was, I truly appreciate the replacement service and how kind you were to a grieving widow.
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Tino Costanzo did an excellent job. Extremely helpful in adding to the efficiency of the operation of our air conditioning unit.
Response from the owner:Hi David, thank you for your kind words! We're so glad to hear that Tino did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
This is the second time Michael King has serviced my AC for AZTIL. He is always pleasant and courteous. He explains all he does to the unit and answers all questions I may have. He is very thorough. Great asset to the company. The trainee (Skyler) with him today has a very good teacher and seems to be on his way to being a positive service tech.
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Lazaro was excellent. Full explanation of services. I would like to get him for any future services. I'd like to add that I was pleased with the vent cleaning that was performed by Alex Molina and his assistant.
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I had woken up to no ac in my house. I contacted aztil on a Saturday at 5 pm and their technician called me back within a half hour. His name was Tino, he said that he would be there within 30 minutes…. And he was! He figured out the problem in 10 minutes and he solved it! Excellent service! Thank you so very much!
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Wow, the scheduling process was a challenge, but our service tech Niko Garza was a grand slam. He more than made up for the scheduling challenges. We’ve been Aztil customers since 2017…. Scheduling was much stronger up until about a year ago, service techs have always been great. Peter, one of the schedulers also can in for the save!

Hey I need to update this 5 Star review, it needs to be a 10…. We needed a new system, boom, done in one day! Our tech, Asiel Barreto was tremendous. He even worked us through the process of using a NEST thermostat- Jackie in the central office rocked us through all the paperwork. This is why we are Aztil for life!
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Jordan was awesome. Nice to work with, fast and efficient.
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Ramon is always on time, polite, knowledgeable and efficient. AC unit has been performing reliably and efficiently.
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Nico was very knowledgeable and did a great job getting our ac working again
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A+ job from two great professionals - Jordan and Hero. A big job - that they explained completely - and they were not only great technically, but very tidy and cleaned everything up after! And really great guys! Highly, highly recommend them - a great team!
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TINO from Aztil is very professional he came and replace a part under warranty at no cost and in no time Aztil is very reliable I’m a happy customer thank you very much for a great service
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Nico my service tech was very knowledgeable, courteous and thorough. Very pleased with my service.
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Dana & Michael did an excellent job replacing my drain lines. They arrived on time & worked hard to finish the job in record time so I was without air conditioning in 1/2 the time expected!
Response from the owner:Hi Lynda, thank you for your kind words! We're so glad to hear that Dana and Michael did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Dana and Niko were great. They did a really good job.
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Antonio & Jordan are highly professional maintenance technicians. They performed a full system overview and my AC is working great! I highly recommend them - Jeff Steinberg
Response from the owner:Hi Paul, thank you for your kind words! We're so glad to hear that Antonio and Jordan did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Luzaro did an excellent job. He got to the problem quickly and is very knowledgeable. Great service. Thank you
Response from the owner:Hi Sherry, thank you for your kind words! We're so glad to hear that Lazaro did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Update: I had Left. A bad review for this company. I had the new manager Anthony reach out to me and he helped me get my whole situation fixed. The solution was to switch back to a basic AC model that would benefit me and also be easy to work on. Anthony was great! He returned all my calls in a timely manner and helped ease my worries. Aztil finally switched out my unit and refunded me the difference. The installers were great and my experience was stellar. Def changed my look on the company. I appreciated the customer service and the communication. New management made a difference.

Previous review 3/2025
This company is the worst!! The previous AC that I used Was sold to them and I thought I could Trust them like the last company! I spent Over 12k for a unit in May 2024 along with a 5yr service contract!!! that the salesman said would be the best unit and solve all my hot spot issues. Well it hasn’t! And because my “best” unit is digital NO TECHNICIAN knows how to work the unit. They are constantly calling tech support and still no one knows. I’ve had 4 different technicians here and no one knows what the hell they are doing!! I have Had technicians out 7 times to my home bc the humidity stays at 65-68%. No one knows how to adjust it. I called For emergency service on a Friday night bc my unit stopped working. They told me they wouldn’t have anyone until Thursday!! Do not use this company. They never call you back. Management does not respond. So unprofessional! I have Been trying to contact someone for over a week and no one ever returns my calls!! DO NOT USE THIS COMPANY.
Response from the owner:Hi Myra, thank you for your kind words! We're so glad to hear that Aztil was able to address your concerns and that you were pleased with the outcome. Thank you for being a valued customer.
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.
Response from the owner:Hi Demora, thank you for your kind words! We're so glad to hear that Albert did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
The 4-stars is because I wasn’t informed of a scheduling change. After a little confusion regarding the appointment time the technician, Michael King contacted me. He arrived at the updated time. Was very professional and kept me informed about the service. He completed the job, cleaned up afterwards and thanked me for being a customer.
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My service call was simple just clean the pipes. I asked the agent what was covered before I accepted and they stated clearing the pipes and other checkup. Well it did not turn out to be TRUE. I was charged for labor , materials(!) and other nonsense. NOT a Happy camper no one likes surprises! They are out of my list.
Response from the owner:Hello Cesar, Thank you for taking time to provide feedback about your experience with our company. We completely understand your frustration and apologize for any dissatisfaction that may have caused your day. We are eager to discuss this experience with you. Please call our customer service manager, Jack. He can be reached at (561) 202-8726. It is our goal to make sure we resolve any issue we can and look forward to speaking with you.
It always seems that the air conditioner breaks down on a hot day.
Well, Aztil is cool under pressure.
First, Paul came out and diagnosed the problem and ordered the replacement parts. Making sure I got the best price.
Then, Dana showed up at my house ready to fix it.
And when it seemed things weren't quite right, Dana returned at 7:30 pm. - ON A FRIDAY NIGHT - to make sure it was A-Okay.

Aztil is definitely the company for our household.
Response from the owner:Hi Robert, thank you for your kind words! We're so glad to hear that Paul and Dana did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Michael King did a superb maintenance job. Plus, he made an extra effort to locate and install a part several hours after his first visit. Well done, Michael.
Response from the owner:Hi George, thank you for your kind words! We're so glad to hear that Michel did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Dana was tech

Came out and went through central system and outside unit. Replaced thermostat as wasn’t reading correctly which was throwing hvac off from normal operation temps
Response from the owner:Hi Andrea, thank you for your kind words! We're so glad to hear that Dana did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Dana Dussaualt did a great job on are annual maintence checkup. Very detailed inspection. Aztec has all ways provided great service.
Response from the owner:Hi Joseph, thank you for your kind words! We're so glad to hear that Dana did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Jordan and hero were phenomenal sealing my air duct system and cleaning my ducts very professional and cleaned up well thank you
Response from the owner:Hi Lynda, thank you for your kind words! We're so glad to hear that Jordan did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.
Response from the owner:Hi Michele, thank you for your kind words! We're so glad to hear that Aztil did an excellent job and that you were pleased with the outcome. Thank you for being a valued customer.

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