Kitchen exhaust is the single item that most often decides whether a restaurant site is viable. It is also the item most often left out of early feasibility, because it is invisible until someone looks at the roof. This is what actually determines requirement and cost.
When a proper kitchen exhaust system is mandatory
- Any gas cooking equipment. If the kitchen runs on natural gas, a proper kitchen exhaust system is required. There is no bench-top substitute for gas.
- Any process producing substantial fumes, smoke or cooking odour. Even with electric equipment, high fume load requires a proper system.
When a bench-top filter may be accepted
Not every food business needs a full exhaust installation. Where the cooking is light and the load is low — a coffee shop with a small amount of bench-top electrical equipment, minimal oil, minimal frying — a bench-top kitchen exhaust filter can sometimes be accepted in place of a full system.
This is assessed case by case on the actual equipment list and the actual cooking process. It is not a category exemption: an ice cream parlour and a cafe with a sandwich press may both qualify, while a cafe that starts frying will not.
The physical constraint nobody mentions
Under the relevant standards, kitchen exhaust must discharge above the roof. That requirement is straightforward on a single-storey building. On anything taller it becomes a cost problem, and on a high-rise it usually becomes a feasibility problem.
| Building | Practical outcome |
|---|---|
| Single storey or low-rise | Vertical riser to roof. The cheapest arrangement. |
| Multi-storey | Longer riser, more ductwork, more fire-rated penetrations. Cost rises with every floor. |
| High-rise | Running a new riser fifteen floors is generally not achievable. The alternative is horizontal discharge. |
Horizontal discharge and electrostatic filtration
Where a vertical riser is not possible, exhaust can sometimes be discharged horizontally at the level of the tenancy through an electrostatic filter, provided a mechanical engineer certifies the design and the discharge location is acceptable to council. It solves the riser problem and introduces a new one: filtration equipment and its cost.
| Item | Indicative cost |
|---|---|
| Electrostatic filter unit | $25,000 – $40,000 per unit |
| Basic exhaust system, typical full installation | approx $45,000 |
| Simplest case including hood | from $15,000 |
Final cost depends on height, duct length, the number of fans, and whether variable speed drives are specified. A horizontal discharge job can therefore carry the full vertical-system cost plus the filtration plant, which is why it is essential to establish this before signing a lease.
The rest of the kitchen support checklist
Exhaust is the headline item, but a commercial kitchen needs the building to support it in four other ways. Each of these appears on the same feasibility review:
| Item | The question to answer |
|---|---|
| Gas | Is natural gas available to the tenancy, or does the kitchen have to run electric? |
| Electrical capacity | Is there enough capacity for the kitchen equipment load, or is a supply upgrade required? |
| Make-up air and return air | An exhaust system extracts air. The building must be able to supply replacement air and return it, or the kitchen will not perform and the space will depressurise. |
| Amenities | Are there compliant toilets, in the numbers the proposed occupancy requires, including an accessible WC? |
How to use this before you commit
Ask three questions of any food site: is the exhaust path achievable, what does the grease trap situation look like, and what is the services capacity. If the answers are yes, existing, and adequate, the fitout proceeds normally. If any answer is no, the cost lands in tens of thousands before a single finish is selected.
See the cost bands and programme, or send us the address and we will review feasibility before you sign.
