Heat, energy & performance
Odour control is only as good as the air reaching it. UV, ozone and carbon stages are designed to neutralise cooking smells - but grease, smoke and heat from a dirty extract overwhelm them before they can. Clean the system and the odour control finally works on what it was built for.
The short answer
Odour control is only as good as the air reaching it. UV, ozone and carbon stages are designed to neutralise cooking smells - but grease, smoke and heat from a dirty extract overwhelm them before they can. Clean the system and the odour control finally works on what it was built for.
The detail
Odour control has a job description. Ozone and UV oxidise odour molecules; activated carbon adsorbs them. Both depend on residence time - UV ozone needs around two seconds of contact, carbon around a fifth of a second minimum - and both depend on the incoming air being mostly odour, not grease and smoke.
A greased, smoky exhaust breaks that. Grease and smoke particles are far larger than odour molecules, so ozone spends its oxidising power breaking those down instead of the smells. Carbon that should be adsorbing odour clogs with grease. The stage is working hard on the wrong thing and letting odour through.
Heat makes it worse still. Above roughly 55 degrees exhaust temperature, the particulate grease filtration is more likely to fail, letting grease bypass into the odour stage, and carbon adsorbs less at higher temperature. A hot, greasy system is exactly the condition in which odour control quietly stops performing.
This matters beyond nuisance. Local Authorities increasingly will not accept carbon as the sole primary odour control and expect a properly working UV or ozone system, referencing DW/172 and EMAQ+ guidance. An odour complaint against a failing system can become an enforcement problem, not just an unhappy neighbour.
What it means for you
If odour is escaping despite a UV, ozone or carbon system being fitted, the extract cleanliness is the first thing to check. Odour control cannot compensate for a system delivering it grease, smoke and over-hot air; it can only work on air that has been properly de-greased upstream.
A clean extract restores the conditions the odour stage was designed for: lower particulate load, cooler exhaust and grease filtration doing its job. The UV or carbon then works on odour molecules, as intended, and gets back to its rated reduction.
Phoenix Duct Clean cleans the whole extract path, including around in-duct UV and grease filtration, so your odour control has clean air to work with and keeps you the right side of Local Authority expectations.
The service behind the guide
Sibling guides
Cleaning before a heatwave · What operators get wrong on heat · Extraction records between cleans
Questions
UV, ozone and carbon are designed to neutralise odour molecules, but grease and smoke particles are far larger and overwhelm them. Ozone breaks down grease instead of smells, and carbon clogs, so odour passes through untreated.
Yes. Above roughly 55 degrees the particulate grease filtration is more likely to fail, letting grease bypass into the odour stage, and carbon adsorbs less at higher temperatures. A hot, greasy system undermines odour control on both counts.
It is the contact time the air needs with the treatment. UV ozone needs around two seconds and activated carbon around a fifth of a second minimum. Too little dwell, or air full of grease, and the stage cannot do its job.
It can. Local Authorities increasingly expect a working UV or ozone system and will not accept carbon alone as primary odour control, referencing DW/172 and EMAQ+ guidance. A failing system can turn a complaint into enforcement.
A clean extract delivers lower particulate load, cooler exhaust and working grease filtration, which are the conditions the odour stage was designed for. The UV or carbon can then work on odour molecules and return to its rated performance.
Phoenix Duct Clean · by the numbers
A dirty extract defeats it. Book a TR19 clean so your odour stage works as designed.