Cost & commercial
A cheap clean often buys a spotless canopy edge and an untouched duct. The work you can see gets done because it is the work you can check; the duct and fan, where compliance and fire risk actually live, are exactly where a budget job quietly stops.
The short answer
A cheap clean often buys a spotless canopy edge and an untouched duct. The work you can see gets done because it is the work you can check; the duct and fan, where compliance and fire risk actually live, are exactly where a budget job quietly stops.
The detail
The commonest shortcut is scope. A low price is usually a canopy-and-filter clean rebadged as a system clean. The hood is degreased, the filters are dunked, and the duct run and fan are left as they were - which is why the price is low, because most of the labour has been skipped.
The second shortcut is access. A real clean opens the system through inspection panels every couple of metres, cleans the internal surfaces with rotary brushes and scrapers, and closes it back up. A budget job cleans only what it can reach without opening anything, so the inside of the duct never sees a brush.
The third is verification. A compliant clean proves itself with before and after photographs from matched positions and micron readings, aiming to leave deposits below 50 microns. A budget clean skips the measurement entirely, so there is no evidence of what was or was not achieved - just an invoice and a clean-looking canopy.
None of this is always dishonest; sometimes the customer asked for a quick tidy and got one. It becomes a problem when a quick tidy is sold, or assumed, as a compliant clean - because the paperwork gap only shows up when an insurer or fire officer asks what is actually inside the duct.
What it means for you
Ask what came back as evidence. A genuine clean produces photographs from inside the duct and fan and micron readings at set points; a budget clean produces a clean canopy and little else. If there are no internal photographs, the internal surfaces were probably not cleaned.
Check the system yourself where you can. Grease still visible at duct joints, a fan that is still coated, or filters that were the only thing degreased are all signs the price bought the visible end only. A borescope check settles it quickly if you are unsure.
Phoenix Duct Clean cleans and photographs the full path and leaves readings behind, so cheap is measured against what was actually done - not against a canopy that looks the part while the duct stays loaded.
The service behind the guide
Sibling guides
what a certified clean includes · how filters and fan access move a quote · extraction myths that cost money
Questions
Because the visible parts - the canopy and filters - are easy to clean and easy to check, so that is where a budget job concentrates. The duct and fan, which you cannot see from the floor, are left untouched, and the shine on the hood hides it.
Before and after photographs from matched positions inside the duct and fan, micron readings at set points, a works summary noting any inaccessible areas, and a TR19 Grease certificate. No internal photographs usually means no internal cleaning.
Not for basic hygiene on the canopy and filters. It is worthless as compliance, because it does not reach or verify the duct and fan that TR19 Grease and your insurer care about.
Ask for the internal photographs and readings, and look at duct joints and the fan yourself. A quick borescope inspection shows the true state of the duct regardless of how clean the canopy edge looks.
A full certified system clean commonly runs around £300 to £600 for a typical single kitchen, more for larger or harder-access systems. The gap over a budget price is the duct, the fan and the proof - the parts that matter.
Phoenix Duct Clean · by the numbers
Book an independent inspection with photographs and readings and see the real state of the duct.