Space Heater Smells Like Fish? (4 Common Causes & Practical Solutions)

When you switch on your space heater expecting a warm, cozy atmosphere but are met with an unexpected fishy smell, it can be quite alarming.

This article dives into the common reasons why a space heater would smell like fish along with practical solutions to ensure a pleasant and safe heating experience.

4 reasons for a space heater to smell like fish (and the fixes!)

In general, there are four main culprits for a space heater that smells like fish:

  • Electrical concerns – wiring and internal components
  • Burning dust or debris on the heating element
  • Moisture and mildew buildup
  • Chemical residue and new space heater smells

Electrical concerns – wiring and internal components

Occasionally, the fishy smell may signal an electrical issue. Overheated insulating materials can emit such an odor. It’s essential to treat this seriously, as it can indicate a larger, potentially hazardous problem.

Unplug your space heater IMMEDIATELY if you smell something fishy!

Over time, the insulation on wires may get damaged, or the wiring may have a short circuit. This can lead to the overheating of electrical components and result in the melting of wires or plastic insulation. As these materials melt, they give off a strong ammonia-like odor, which smells similar to fish.


  • Overheated insulation on wires.
  • Short circuits leading to melting wires or plastic insulation.

To address this issue:

  1. Unplug the heater and inspect the wiring for visible damage.
  2. Check the electrical outlets for any signs of overheating or melting.
  3. If you find any abnormalities, contact a professional electrician to fix the issue.

Burning dust or debris on the heating element

When your space heater smells strange, it could be due to dust and debris accumulating on the heating elements. Over time, dust can build up and become trapped on the heater’s components. When the heater operates at high temperatures, the dust starts to burn, releasing a foul odor.


  • Regular burning smell upon turning on the heater.

To prevent this issue, make sure you regularly clean and maintain your space heater by:

  1. Turning off and unplugging the unit.
  2. Using a soft brush or vacuum to gently remove dust and debris from the heating elements.
  3. Reassembling and testing the heater to ensure the smell has dissipated.

Moisture and mildew buildup

Another cause of unpleasant smells from a space heater is moisture and mildew. When the heater is exposed to damp environments, such as a poorly ventilated room or basement, moisture can accumulate inside the device.

This moisture may lead to mildew growth, which releases a musty smell when the heater is in use.


  • The heater produces a damp, moldy smell.
  • Visible mold or mildew on or inside the heater.

To avoid moisture-related issues, follow these steps:

  1. Store your space heater in a dry, well-ventilated area when not in use.
  2. Periodically inspect the unit for signs of moisture or mildew.
  3. If you spot any visible mildew, clean the affected areas with a mild detergent and allow the unit to thoroughly dry before using it again.

Regular maintenance and proper storage can also extend your space heater’s lifespan and improve its overall performance.

Chemical residue and new space heater smells

Lastly, the fishy smell might be due to chemical residues or the “new heater smell”. Some space heaters may have residual chemicals from the manufacturing process, which can produce a fishy odor when heated.

Additionally, a new space heater might have a distinct smell caused by the heating of various internal components for the first time. This should go away on its own after a few uses.


  • A distinct smell when using a new heater.

To eliminate chemical residue and new heater smell:

  1. Run the heater in a well-ventilated area for a few hours to allow the chemical residue to burn off.
  2. Place the heater outside or in a garage to avoid indoor exposure to fumes.
  3. Repeat this process until the smell is no longer present.

By addressing these potential causes of fishy smells in your space heater, you can enjoy a more pleasant and safe heating experience.

Routine and Regular Maintenance to Prevent a Space Heater from Smelling Like Fish

Maintaining and cleaning your space heater not only ensures optimal efficiency but also extends its lifespan and enhances safety. Here’s a step-by-step guide to best care for your space heater:

Always Unplug Before Cleaning

Safety first! Ensure your space heater is turned off, unplugged, and has cooled down before you attempt any cleaning or maintenance.

Check the Manual

Before you start, consult the manufacturer’s manual. Different heaters may have specific guidelines or precautions to consider.

External Cleaning

Use a soft, damp cloth to wipe down the exterior of the heater. Avoid using abrasive pads or strong chemicals, which might damage the surface.

For hard-to-reach areas or vents, a soft brush or a can of compressed air can help in removing dust and dirt.

Filter Maintenance (if applicable)

  • Some heaters come equipped with filters that help purify the air. These filters accumulate dust over time and should be cleaned regularly.
  • Remove the filter as per the manufacturer’s guidelines.
  • Some filters are washable; use mild soap and warm water. Rinse thoroughly and allow it to dry completely before reinserting.
  • Replace filters as recommended by the manufacturer.

Internal Cleaning

  • If you notice a buildup of dust or debris inside the heater, consider using a vacuum with a nozzle attachment to gently remove it.
  • For deeper internal cleaning, it might be best to consult with a professional or the manufacturer.

Check the Cord

Inspect the power cord periodically for any signs of wear, fraying, or damage. If you notice any of these signs, it’s safer to replace the heater or have the cord professionally repaired.

Safe Storage

If you won’t be using your space heater for a prolonged period, especially during warmer months:

  • Clean it thoroughly.
  • Store it in its original box or a clean, dry place where it’s free from dust and moisture.
  • Ensure it’s kept away from direct sunlight and flammable materials.

Check Out Our Complete Guide to Space Heaters!

If you enjoyed this post, check out our complete guide to space heaters for more information on space heater types, safety features, troubleshooting common issues, and how to choose the right space heater for your needs!

Let Us Know How We’re Doing!

Did this expertly prepared resource answer your question?

Do you have another question about home maintenance, home improvement projects, home appliance repair, or something else?

Get more information, send in questions and keep the discussion going by contacting the I’ll Just Fix It Myself company customer service team at at 1-800-928-1490 or Email us at [email protected]