Drop the aluminium mesh filters and soak them flat in hot water with a non-caustic degreaser. Never put them in a dishwasher, which oxidises aluminium grey permanently. On a hood this age, the ducting above it is worth checking as well, because a duct lined with hardened fat is a fire risk.
Westinghouse rangehoods are fitted, used daily and forgotten more thoroughly than almost any appliance in an Australian kitchen. They are simple, they are cheap to replace and they very rarely fail outright, which is exactly why so many of them are twenty years into a job nobody has ever checked.
The general method for any hood, filters out, soaked flat, then the impeller housing behind them, is on our rangehood cleaning guide. Three things are worth knowing about this brand in particular.
The filters are aluminium mesh, and the dishwasher ruins them
Almost every Westinghouse hood uses aluminium mesh rather than stainless baffles: several layers of fine expanded mesh in a frame, held by a sprung catch on the underside.
Mesh must never go in a dishwasher. Dishwasher detergent is strongly alkaline, it oxidises aluminium, and the filter comes out a chalky grey that will not clean off and does not come back. On some frames it also softens the adhesive holding the assembly together.
Soak them flat instead, in hot water with a non-caustic degreaser, for an hour. Work them gently with a soft brush along the mesh rather than across it, because mesh distorts easily and a distorted filter no longer sits flush against the hood, which means grease bypasses it completely from then on.
Replacement mesh filters are inexpensive. If a soak does not clear one, it is finished, and it is far cheaper to replace than to let the fan do the filtering instead.
The ducting, which is the real question on a hood this old
This is the part specific to the brand, and it is specific because of the age profile rather than the engineering.
A Westinghouse hood installed in the early 2000s has had twenty years of cooking vapour passing through its duct. Some of that fat condenses on the duct wall and hardens. Nobody has ever seen it, because the duct disappears into a ceiling or a wall cavity and there is no reason to look.
That matters for two reasons. A duct partly lined with hardened fat moves noticeably less air, so the hood is running without doing much. And a duct heavily lined with fat is a genuine fire risk, which is the reason commercial kitchens have their ducting cleaned on a schedule and domestic ones almost never do.
You can wipe as far up the duct as your arm reaches with the filters out. Beyond that it needs equipment. On a hood that has run for a decade or more without attention it is worth having looked at.
It shares a platform with Chef and Electrolux
Westinghouse, Chef and Electrolux are all part of the same group, and their hoods frequently share filter dimensions and motor assemblies. If a Westinghouse-badged replacement filter is hard to find for an older unit, the equivalent Chef or Electrolux part is worth checking against the dimensions.
The slide-out models, and why they hide more
A large share of Westinghouse hoods are the slide-out type: a shallow unit fitted under a cupboard with a pull-out visor that extends over the hob when you want extraction and pushes back flush when you do not.
They are sensible in a small kitchen and they collect grease in a place nobody looks. The visor runs on side channels, and those channels fill with a mixture of fat and dust that eventually makes the slide stiff. People then stop pulling the visor out, which means the hood is running with its intake half covered, which means it extracts very little while appearing to work normally.
If your slide-out has become stiff, that is not the mechanism wearing out. Clean the channels with a cloth and a non-caustic degreaser, dry them, and it will usually move freely again. It is a five minute job that restores extraction people have quietly been living without for years.
The other consequence is that the filter behind the visor is out of sight and out of mind in a way a canopy filter never is. On a canopy hood you look up at a greasy filter every time you cook. On a slide-out you see a clean white or stainless front.
What actually goes wrong
Grey, chalky filters from a dishwasher cycle. The most common avoidable damage on this brand.
A distorted mesh frame from scrubbing too hard, after which grease goes straight past it.
Twenty years of unexamined ducting, which is the thing that actually limits the hood.
A hood that was never switched on much, because it was noisy, so the grease went onto the walls and the oven below instead.
Should you do it yourself?
Do it yourself for the filters. Ten minutes of attention and an hour of soaking, every couple of months.
Get someone in for the impeller housing, for a hood that smells or rattles, and particularly for anything more than a decade old where the ducting has never been looked at.
Most people book it with the Westinghouse cooktop below and the Westinghouse oven under that.