Cost & commercial
Every extract system is eventually either cleaned or replaced. Cleaning is a modest, planned cost; replacement is what neglect leads to - a failed fan, degraded ductwork, a fire risk you cannot defend, and the lost trade of a kitchen that has had to stop.
The short answer
Every extract system is eventually either cleaned or replaced. Cleaning is a modest, planned cost; replacement is what neglect leads to - a failed fan, degraded ductwork, a fire risk you cannot defend, and the lost trade of a kitchen that has had to stop.
The detail
The fan goes first. Grease that is never cleared reaches the impeller, drives it out of balance and wears the bearings until the motor overheats and fails. A replacement unit and install commonly runs £500 to £3,000, and far more on a large roof-mounted system - a cost that regular cleaning would have deferred for years.
The ductwork degrades next. Heavy, baked-on polymerised grease is harder and dearer to remove than routine deposits, and left long enough it damages surfaces and joints. What would have been a straightforward clean becomes remedial work, and in the worst cases sections of duct or filters need replacing outright.
The fire risk becomes the real liability. Grease in the duct is combustible fuel, and extract fires are common enough that a duct fire happens on average every nine days in Greater London alone. A neglected system is both more likely to ignite and, without a certificate, far harder to defend to an insurer afterwards.
Then there is lost trade. A failed fan or a fire closes the kitchen, and a closed kitchen earns nothing while it is fixed and re-certified. The replacement cost is visible on an invoice; the lost revenue and the emergency premiums around it are the quiet, larger half of what neglect actually costs.
What it means for you
Set the two side by side. A scheduled certified clean is a few hundred pounds a visit - around £300 to £600 for a typical system - and keeps the fan, the duct and the compliance intact. Replacement is thousands, unplanned, and comes bundled with closure and a fire risk you carried in the meantime.
Cleaning is not just cheaper, it is the thing that prevents the replacement. Keeping grease off the fan and out of the duct holds the whole system near the top of its service life rather than driving it to early failure. Neglect does not avoid the cost - it converts a small planned one into a large forced one.
Phoenix Duct Clean keeps systems cleaned, inspected and certified so replacement stays a distant, chosen upgrade rather than an emergency - and the cost of neglect never lands on your kitchen at the worst possible time.
The service behind the guide
Sibling guides
what an extraction clean costs in 2026 · why quotes vary so much · setting a baseline at fit-out
Questions
Cleaning, without question. A scheduled clean is a few hundred pounds and keeps the system alive; replacement runs into thousands, arrives unplanned, and brings closure and lost trade with it. Neglect converts the small cost into the large one.
The fan. Grease reaches the impeller, unbalances it and wears the bearings until the motor fails. Then the ductwork degrades as grease bakes hard, and the fire risk climbs the whole time.
Significant. Grease in the duct is combustible, and extract fires are frequent - roughly one every nine days in Greater London. A neglected system is more likely to ignite and, with no certificate, harder to defend to insurers.
No. A new fan or duct in a kitchen that still is not cleaned simply starts the same decline again. Cleaning on a schedule is what protects any system, new or old, from being driven to early failure.
The lost trade of a closed kitchen, the emergency premiums on out-of-hours replacement, and the exposure of running an undefendable fire risk. Those quiet costs usually outweigh the visible replacement figure.
Phoenix Duct Clean · by the numbers
Book a clean and inspection and keep replacement a distant choice, not an emergency.