If you’re noticing a odor from your heat pump, it’s attempting to tell you that something is up. We’ve developed a list of the most commonly encountered 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 most likely mold growing on moist evaporator coils or in the ductwork. This heat pump odor is often referred to 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 couple of things wrong:

  • Motor is too hot
  • Wiring issue
  • Plastic components or coating is melting
  • Other mechanical issue

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

3. Heat Pump Smells Like Sulfur

Normally when you smell a rotten egg smell, you’re dealing with a gas leak. But your heat pump doesn’t utilize natural gas. If your heat pump smells like sulfur, a little animal may have crawled inside it for warmth and died. One of our Thurston Heating & Air Conditioning technicians can remove the smell by cleaning your heat pump.

4. Heat Pump Smells Like Sewer

As we mentioned before, your heat pump is electric, so any rotten egg smells are linked to a gas leak elsewhere. If your heat pump smells like sewer, you might currently have a backed-up or broken sewer line. We suggest getting in touch with a company that does sewer line repair.

5. Heat Pump Smells Like Burning

You might have an electrical issue if your heat pump smells like burning, burning plastic or burning rubber. This burning smell can be caused by melting plastic on electrical wires. Electrical issues in HVAC systems are unsafe and could cause a fire. If you notice this smell, turn off your heat pump at the breaker and get a hold of us at .

6. Heat Pump Defrost Cycle Smells

Like we mentioned above, a dirty socks smell can happen when your evaporator coils need sanitizing. You might encounter this smell when your heat pump is in defrost mode.

It’s typical for your heat pump to have to turn on defrost mode during heating season. When the air is much colder, frost can form fast on the coils from condensation and interfere with heating. During defrost mode, your heat pump temporarily switches to air conditioning to clear away the frost.

Having a Thurston Heating & Air Conditioning HVAC technician clean the coils will help eliminate the odor.

Depend on for Your Heat Pump Repair Needs

It can be confusing to troubleshoot your heat pump by yourself. Your comfort matters to us at Thurston Heating & Air Conditioning, so you can count on our experts to help you when you need us. When you need heat pump repair in that you can rely on, call us at .