If you’re discovering a odor from your heat pump, it’s trying to tell you that something is wrong. We’ve put together a list of the top six heat pump smells, what causes them and how you can fix them.

  1. Heat pump smells musty
  2. Heat pump smells like fish
  3. Heat pump smells like sulfur
  4. Heat pump smells like sewer
  5. Heat pump smells like burning
  6. Heat pump defrost cycle smells

1. Heat Pump Smells Musty

If your heat pump smells musty, there’s likely mold growing on damp evaporator coils or in the ductwork. This heat pump odor is often known as dirty sock syndrome. You can deter this by scheduling regular heat pump maintenance and air duct cleaning.

2. Heat Pump Smells Like Fish

If your heat pump smells like fish, there could be a few things wrong:

  • Overheated motor
  • Wiring problem
  • Plastic components or coating is melting
  • Other mechanical problem

Electrical problems are serious, so turn your heat pump system off right away at the breaker box and contact us at for heat pump repair.

3. Heat Pump Smells Like Sulfur

Often when you have a rotten egg smell, you’re dealing with a gas leak. But your heat pump doesn’t run on natural gas. If your heat pump smells like sulfur, a little animal may have creeped inside it for warmth and died. One of our Pepper AC & Heat experts can eliminate the smell by cleaning your heat pump.

4. Heat Pump Smells Like Sewer

As we reviewed above, your heat pump is electric, so any rotten egg smells are tied to a gas leak in another place. If your heat pump smells like sewer, you might have a backed-up or broken sewer line. We recommend getting in touch with a company that does sewer line repair.

5. Heat Pump Smells Like Burning

You might be dealing with an electrical problem if your heat pump smells like burning, burning plastic or burning rubber. This burning smell can be due to melting plastic on electrical wires. Electrical problems in HVAC systems are unsafe and could lead to a fire. If you notice this smell, shut off your heat pump at the breaker and get a hold of us at .

6. Heat Pump Defrost Cycle Smells

Like we talked about previously, a dirty socks smell can happen when your evaporator coils need sanitizing. You might notice this smell when your heat pump goes into defrost mode.

It’s ordinary for your heat pump to have to switch on defrost mode during heating season. When the air is much cooler, frost can form quickly on the coils from condensation and restrict heating. During defrost mode, your heat pump briefly switches to air conditioning to clear away the frost.

Having a Pepper AC & Heat HVAC technician clean the coils will help eliminate the smell.

Depend on for Your Heat Pump Repair Needs

It can be hard to troubleshoot your heat pump by alone. Your comfort matters to us at Pepper AC & Heat, so you can count on our professionals to help you when you need us. When you need heat pump repair in that you can depend on, call us at .