Gazco Onyx Athos 5 Woodburning Stove

The Gazco Onyx Athos 5 is a woodburning stove that brings together heritage-inspired aesthetics and genuinely impressive modern performance. Built around a robust steel body with a cast-iron door, it carries a timeless character that suits classic cottages, period properties, and traditionally decorated living rooms alike. The distinctive anodised door handle — finished in champagne at each end with a black knurled grip — adds a refined, considered detail that sets it apart from more utilitarian designs.

Heating performance is at the heart of this stove. With a nominal output of around 4.8 kW and efficiency figures of up to 82%, the Athos delivers strong, consistent warmth for small to medium-sized rooms while making the most of every log you burn. A convector heat system circulates warm air around the stove body, spreading that heat more effectively throughout the space rather than simply radiating from a single point.

Combustion quality is equally impressive. Tertiary air jets support a cleaner, more complete burn, while the airwash system keeps the glass clear so you can enjoy an uninterrupted view of the flames. The stove is fully Ecodesign compliant and holds DEFRA Smoke Control Area exemption, meaning it can be used with wood in designated urban smoke control zones — a genuinely useful credential for city and town centre installations.

Installation flexibility is a practical strength of the Athos. It is compatible with a 12 mm hearth and can be connected to an optional external air supply, making it well suited to modern, well-insulated homes. For best results, burn well-seasoned hardwood logs with a moisture content below 20%, and always have the stove installed by a HETAS-registered professional. Fitting a carbon monoxide alarm in the same room is strongly recommended.

Specifications

• Heat Output: 2kW-6kW
• Nominal Heat Output: 4.8kW
• Efficiency: 82.0%
• Energy Efficiency Rating: A+
• Flue Diameter: 128mm
• Flue Type: Top and Rear Exit
• SIA Ecodesign: Yes
• Cleanburn Technology: Yes
• Airwash Technology: Yes
• Dimensions (D x W x H): 367 × 500 × 596 mm
• Heat System: Convector
• Compatible Hearth: 12mm