Heat pumps are a great way to keep your home comfortable in both hot and cold weather. However, when a heat pump starts to give off strange odors, it can be a sign of something more serious. Common heat pump odors you should never ignore include musty smells, burning smells, and electrical odors. Keep reading to find out why these odors are a cause for concern and what you can do about them.

Fishy Smell

fishy smell from air conditioner equipment is a common problem that many homeowners encounter. This odor can be caused by a variety of sources, ranging from an accumulation of dirt and dust on the evaporator coils to the presence of mold or mildew in the system. The most likely cause of this unpleasant smell is water buildup within the heat pump’s condensate drain line, which may have become clogged with debris or even algae growth as it sits stagnant. In some cases, this smell could also be coming from inside your ductwork if there are any gaps along its seams allowing outside air to enter.

In some instances, if the fishy smell is coming from your heat pump, it could be indicative of a plastic component that is too hot and melting. The fishy odor could also mean there are wiring issues. Whatever the problem, you need to call a technician.

Burning Smell


A burning smell coming from a heat pump or air conditioner can be very concerning, as it can indicate a serious problem with the system. In some cases, the smell may be harmless and not require any action, but in other cases, it could be a sign of a more serious issue that requires immediate attention. If the smell is accompanied by smoke or visible flames, it is important to contact a professional immediately. If any visible signs do not accompany the smell, it is still important to be aware of potential causes and take action if necessary.

One common cause of a burning smell coming from the HVAC system is a dirty air filter. When the filter is clogged with dirt, dust, and other debris, the airflow is restricted and can cause the system to overheat. This can lead to an overheated blower motor, which can give off a burning smell. It is important to regularly check and replace air filters to prevent this from occurring.

Another possible cause of a burning smell is an electrical issue. Electrical problems can occur in a variety of ways and can cause the system to malfunction. If a burning plastic smell accompanies a burning smell, it is important to turn off the system and contact a professional as soon as possible.

Finally, a burning smell can also indicate that something has become lodged in the system. Small objects such as paper, toys, or fabrics can become wedged in the equipment and cause the motor to overheat. If this is the case, it is important to turn off the unit immediately and contact a professional to remove the object safely.

Musty Smell


Musty smells are one of the most common smells coming from heaters and air conditioners. The growth of mold, mildew, and other fungi in the HVAC system causes this type of smell. Specific areas of concern include the evaporator coil, condensate pan, and drains. The damp, dark environment of the air conditioner provides the perfect breeding ground for these organisms. A musty smell is usually the result of an accumulation of condensation in these areas, which in turn leads to the development of mold and mildew. A thorough cleaning and annual seasonal maintenance can help prevent this type of smell.

Additionally, a musty smell from the air conditioner can also be the result of a clogged or dirty air filter. A dirty air filter prevents air from flowing freely through the air conditioner and can also allow contaminants to circulate through your home, creating a musty smell. In order to prevent musty smells from occurring, it is important to check and replace the air filter at least every three months. A clean air filter can also ensure quality indoor air.

Overall, common odors from your heat pump or air conditioner should never be ignored as they may indicate a serious problem. Early detection and diagnosis of a problem can help prevent damage to the system and more costly repairs in the future.