Range Hood to Gas Cooktop Clearance: 650mm Rule Explained (AS/NZS 5601.1:2022)
One of the most common questions gas fitters ask is: "Is it 600mm or 650mm from the cooktop to the rangehood?" The answer depends on when the kitchen was built — and it's a distinction that trips up both gas fitters and kitchen installers regularly.
When AS/NZS 5601.1:2022 was published on 30 September 2022, it increased the minimum overhead clearance from a gas cooking appliance to a rangehood from 600mm to 650mm. This change was adopted across all Australian states by 31 March 2023. But the old 600mm rule still applies in specific circumstances.
This guide explains exactly when each measurement applies, where to measure from, and what to do when you encounter non-compliant installations.
The 650mm Rule: New Installations
For all new kitchen installations (new builds and full kitchen renovations) completed after 30 March 2023, the minimum clearance requirements are:
| From | To | Minimum |
|---|---|---|
| Top of trivet (cooking vessel support) | Lowest part of rangehood | 650mm |
| Top of trivet | Lowest part of exhaust fan (no hood) | 750mm |
| Top of trivet | Any combustible surface (absolute minimum) | 450mm* |
*If any combustible surface is between 450mm and 650mm above the trivet, it must be thermally protected for the full width and depth of the cooking surface per AS/NZS 5601.1 Appendix C.
Key Point: Manufacturer's instructions always take precedence
If either the gas cooktop manufacturer OR the rangehood manufacturer specifies a clearance greater than 650mm, you must use the greater distance. Always check both sets of installation instructions before finalising the rangehood height.
The 600mm Rule: Existing Installations
For existing kitchens built before 30 March 2023, the previous 600mm minimum clearance can still apply — but only under specific conditions:
| From | To | Minimum |
|---|---|---|
| Highest part of highest burner or hob | Lowest part of rangehood | 600mm |
| Highest part of highest burner or hob | Lowest part of exhaust fan | 750mm |
The 600mm rule applies ONLY when:
- The kitchen was built and the original cooktop installed before 30 March 2023
- You are replacing the cooktop with a new one AND the new cooktop manufacturer does not specify a greater clearance
- The rangehood is not being replaced (if a new rangehood is installed, check its manufacturer specs)
If the kitchen is undergoing a full renovation (new cabinetry, new rangehood, new cooktop), the new 650mm minimum applies regardless of when the house was built.
Where to Measure: The Critical Difference
One of the most important changes in AS/NZS 5601.1:2022 is where you measure from. This catches out many gas fitters who learned the old method:
New kitchens (post 30 March 2023):
Measure from the top of the trivet (the cooking vessel support surface — where the pot sits) to the lowest part of the rangehood.
Existing kitchens (pre 30 March 2023):
Measure from the highest part of the highest burner (or highest part of the hob) to the lowest part of the rangehood.
The practical difference between these two measurement points is typically 5-15mm, depending on the cooktop model. On a new installation, the trivet (pan support) is usually slightly higher than the burner crown, so the effective clearance to the rangehood is slightly less when measured from the trivet.
What About Wok Trivets?
Removable accessories such as a wok trivet that sits on top of the standard hob trivet are not counted when taking the measurement. Similarly, minor elevations in trivets designed for wok burners are not included. You measure from the standard cooking vessel support surface only.
Why the Change from 600mm to 650mm?
The clearance was increased to align AS/NZS 5601.1 with the international safety standard IEC 60335-2-31 (safety of range hoods and other cooking fume extractors). The international standard already required 650mm, and the Australian/New Zealand standard was updated to be consistent.
The change also reflects modern cooktop designs with higher-output burners (particularly wok burners rated at 14-20 MJ/h) that produce more radiant heat than older models. The additional 50mm provides a greater safety margin for the rangehood components, wiring, and any grease filters above.
Combustible Surface Protection (Appendix C)
If any downward-facing combustible surface (including the underside of overhead cupboards) is less than 650mm above the trivet in a new kitchen, or less than 600mm in an existing kitchen, the entire surface must be thermally protected.
The protection must cover the full width and depth of the cooking surface and comply with the methods specified in AS/NZS 5601.1 Appendix C. Common protection methods include:
- Non-combustible board (calcium silicate, fibre cement) at least 6mm thick
- Sheet metal with an air gap behind it
- Purpose-built heat shields rated for the application
The absolute minimum clearance — even with full thermal protection — is 450mm. No combustible surface may be closer than 450mm to the cooking vessel support, regardless of protection.
Common Scenarios and What Applies
| Scenario | Minimum Clearance | Measure From |
|---|---|---|
| New build — new kitchen, new cooktop | 650mm | Top of trivet |
| Full kitchen renovation (new cabinetry + rangehood) | 650mm | Top of trivet |
| Existing kitchen — replacing cooktop only | 600mm* | Highest burner/hob |
| Existing kitchen — replacing rangehood only | Check manufacturer | Per manufacturer spec |
| Existing kitchen — benchtop/door replacement only (same cooktop) | 600mm | Highest burner/hob |
*Only if the new cooktop manufacturer does not specify a greater clearance in their installation instructions.
What If the Existing Clearance Is Less Than 600mm?
If you're replacing a gas cooktop in an existing kitchen and the current clearance to the rangehood is less than 600mm, the rangehood must be raised to achieve at least 600mm (or the manufacturer's specified clearance, whichever is greater).
The 600mm "existing installation" allowance is not a blanket exemption — it only permits retaining a compliant 600mm clearance that was correct under the previous standard. It does not permit installing below 600mm.
Exhaust Fans vs Rangehoods
There's an important distinction between a rangehood and a standalone exhaust fan mounted above a cooktop:
- Rangehood: 650mm minimum (new) or 600mm (existing) from trivet/burner to the lowest part of the hood
- Exhaust fan (no hood canopy): 750mm minimum in all cases — both new and existing installations
The 750mm requirement for exhaust fans reflects the fact that without a hood canopy to capture and direct cooking fumes, the fan motor and wiring are more directly exposed to rising heat and grease-laden air.
Common Mistakes Gas Fitters Encounter
- Kitchen installer sets rangehood at 600mm in a new build: The cabinetmaker or kitchen installer may use the old 600mm measurement. If you're connecting the gas cooktop, verify the clearance before commissioning. If it's less than 650mm, the rangehood must be raised before you can sign off.
- Measuring from the wrong point: Measuring from the benchtop surface instead of the trivet top. The trivet sits above the benchtop cutout — the measurement must be from where the pot actually sits.
- Ignoring manufacturer specs: Some high-output cooktops (especially those with 20+ MJ/h wok burners) specify 700mm or even 750mm clearance. The standard's 650mm is only the minimum — manufacturer specs override.
- Forgetting the rangehood manufacturer: You need to check BOTH the cooktop AND the rangehood installation instructions. Some rangehood manufacturers specify 700mm minimum for their product.
- Overhead cupboard too low: Even if the rangehood is at 650mm, if overhead cupboards on either side are at 580mm above the trivet, those combustible surfaces need thermal protection per Appendix C.
Frequently Asked Questions
Does the 650mm rule apply to electric cooktops?
AS/NZS 5601.1 is a gas installation standard and only applies to gas cooking appliances. Electric and induction cooktops are covered by the rangehood manufacturer's installation instructions and AS/NZS 3000 (Wiring Rules). However, many rangehood manufacturers specify 650mm minimum regardless of fuel type.
Can I install a gas cooktop if the rangehood is at 620mm and it's an existing kitchen?
No. Even in an existing kitchen, the minimum is 600mm measured from the highest burner/hob point. At 620mm from the benchtop, the actual clearance from the trivet top may be less than 600mm depending on the cooktop model. Measure from the correct point and verify it meets at least 600mm (or the manufacturer's spec if greater).
What if the customer refuses to raise the rangehood?
You cannot commission a non-compliant gas installation. If the rangehood cannot be raised to achieve the required clearance, you must decline to connect the gas cooktop and document the reason. Issuing a compliance certificate for a non-compliant installation exposes you to personal liability and potential licence sanctions.
Does this apply to commercial kitchens?
Commercial kitchen clearances are covered separately under AS/NZS 5601.1 Clause 6.10.2 and are generally more prescriptive. Commercial installations also need to comply with AS 1668.2 (mechanical ventilation) and local council/fire authority requirements. This article covers domestic installations only.
My existing rangehood is at exactly 600mm. Do I need to change anything?
If the kitchen was installed before 30 March 2023 and you're not replacing the cooktop or renovating the kitchen, the existing 600mm clearance remains compliant. You don't need to retrospectively raise the rangehood. The new standard is not retrospective for existing compliant installations.
This article is general guidance only and does not constitute legal advice. Always verify compliance requirements with your state's technical regulator and the current edition of AS/NZS 5601.1 before commencing work. Information current as of July 2026.