Diagnosis
That burning-dust smell is exactly that—dust, lint, and pet hair that’s settled on the cold ceramic element and in the vents getting cooked off when the heater cycles on. It’s normal at the start of the season but should be cleaned out.
How to Fix It
Unplug the heater and let it cool for at least an hour. 1) Use the crevice tool on your vacuum to thoroughly clean the front grille (where the hot air comes out) and the rear intake vents. 2) For a deeper clean, remove the four screws on the bottom plate to take off the outer shell. 3) Carefully vacuum the interior, focusing on the ceramic heating element and the fan blades. 4) Use a can of compressed air to blow dust out of the tight spaces around the element. 5) Reassemble. Run the heater on high for 15 minutes in a well-ventilated area to burn off any remaining residue; the smell should clear.
If That Didn't Work
If a strong plastic or electrical burning smell persists after cleaning, something internal might be overheating. Immediately unplug it and discontinue use. This could indicate a failing component or wiring issue.
Heads Up
Never use water, liquid cleaners, or a damp cloth to clean the inside of the heater. You don’t want any moisture near the electrical parts or the ceramic element, as it can cause damage or a short when you plug it back in.