Your bathroom exhaust fan is filled with dirt - here’s how to clean it

Ideally, you want a way to remove the blades so you can put this part in a sink or bucket filled with warm, soapy water. Photo / 123rf

When a fan starts to sound loud and no longer keeps windows and mirrors from fogging up, it’s time for a deep cleaning.

Q: I installed a Panasonic FV-11VHL2 WhisperWarm exhaust fan in one of our bathrooms. The maintenance instructions cavalierly say: “Remove dust and dirt from the fan body using a vacuum cleaner.” No way. Not only can’t you get to the fan, no vacuum will ever dislodge the encrusted dirt. It has to be scraped off. I’ve tried using wooden dowels (too thick to reach corners); old toothbrushes (too large to fit between blades and bristles too soft); Q-tips (one or two passes and they fray or the stem bends or breaks); a letter opener (the most useful, but it risks scratching the plastic blades) and a damp cloth (good for only a pass or two before it frays). It’s all tedious, one-blade-at-a-time cleaning with repeated passes for each of the 67-plus blades. Is there an easier way?

A: Manufacturers who say to clean bathroom exhaust fans with just a vacuum aren’t being straight with their customers. While it’s true frequent vacuuming keeps fans cleaner, often that’s not enough. High humidity combines with dust to create a caked-on grime that has to be washed or scraped away.

It’s important to do this task regularly; a heavy buildup reduces a fan’s efficiency. When a fan starts to sound loud and no longer keeps windows and mirrors from fogging up, it’s time for a deep cleaning. And to do that, you need unencumbered access to the fan blades. Ideally, you want a way to remove the blades — which are often referred to as a squirrel cage — so you can put this part in a sink or bucket filled with warm, soapy water.

To do a deep clean, start by switching off power at the circuit. Then gather your tools. Position a ladder or stool under the fan, and have a headlamp or work light handy. You’ll also need a screwdriver and a socket wrench.

Remove the grille, which typically involves working your fingers in around opposite edges and pulling down, then pinching each pair of spring wires above to release the catches that hold them to the metal box.

If the grille includes an LED light unit, unplug it and remove any screws so you can clean the grille itself in a sink filled with warm water and a little hand dishwashing detergent. To unplug the light, you might need to press a tab, then pull. If the grille has a light unit that isn’t removable, clean the grille with a brush and a vacuum or compressed air; don’t soak electronics in water.

If you find it difficult to decipher parts drawings, you can ask the technical adviser to walk you through the process. Photo / 123rf

The WhisperWarm model you have doesn’t have an LED light built into the grille, but it does have a fluorescent light unit between the grille and the fan, as well as a heater with its own fan that blows hot air down while the exhaust fan moves humid air up and out. To clean the exhaust fan, you need to remove the light unit first. But you’d never know that from the official maintenance instructions. Illustrations show how to remove the grille and wash it in a sink. Then the text says to “remove dust and dirt from the fan body using a vacuum cleaner” and to use a cloth dampened with kitchen detergent to “remove any dirt from the fan body.” But the illustrations show a vacuum wand and a gloved hand with a cloth wiping the fluorescent tubes of the light module — not the fan. The instructions don’t say how to remove the light unit or even hint that it’s necessary.

To learn how to do that, and to remove the fan so you can easily clean the squirrel cage in water, look up the installation instructions for your fan and scrutinise an exploded view of the parts, especially the screws that hold each layer in place. (If you don’t know the model, remove the grille and look for a label inside.) If you find it difficult to decipher parts drawings, or if you can’t find them online, call the company’s technical advice number, ask to have a PDF emailed to you, then ask the technical adviser to walk you through the process. For Panasonic, the number is +64 9 272 0100 in New Zealand. Louis — he wasn’t allowed to give his last name — gave step-by-step instructions for your fan model and identified the relevant pieces by the part numbers on the diagram.

To remove the light unit, take out two screws and unplug the unit from the housing, which might involve pressing on a tab to release the plug. Then remove the three or four screws (Louis said there are only three even though the diagram says four) that hold the fan unit to the metal box. The box itself and the heater assembly stay attached to the ceiling. Pull down the fan unit and unscrew the metal on the fan housing, which is plastic. Using a socket wrench, remove the central nut that holds the squirrel cage in place. Then you can clean it with warm, soapy water and a toothbrush or other narrow scrub brush. Rinse and dry and put everything back in reverse order.

As with many home repairs, watching a YouTube video can be very helpful. There doesn’t appear to be one for the model you have, but there is one for basic WhisperWarm fans minus the fluorescent unit and the heater. The process of removing the fan assembly is basically the same for many exhaust fans, although the screw placements may differ.

- Additional reporting by NZ Herald