Nestor Martin Harmony III Multi Fuel Stove
The Nestor Martin Harmony III Multi Fuel Stove combines traditional cast iron craftsmanship with modern combustion technology to deliver powerful, efficient heating for larger living spaces. It burns both seasoned logs and approved smokeless fuels, giving you the flexibility to choose the fuel that best suits your home while preserving the timeless appeal of a classic stove.
Nestor Martin manufactures the Harmony III entirely from premium cast iron, ensuring exceptional durability and excellent heat retention. Its substantial size and impressive 12kW heat output make it an ideal choice for larger rooms, open-plan living areas, and properties that require greater heating performance without compromising on style.
Classic Design with Practical Features
The Harmony III stays true to the traditional styling that has made Nestor Martin stoves so highly regarded. Clean lines, solid cast iron construction, and a generous viewing window allow the flames to become the focal point of the room.
A practical side-loading door makes refuelling simple, especially when using logs up to 500mm long. This thoughtful design makes loading wood more convenient while helping reduce the ash and debris that can escape into the room during refuelling.
Whether you install it within a traditional fireplace opening or as a freestanding feature, the Harmony III adds warmth and character to a wide range of interiors.
Powerful and Efficient Heating Performance
The Harmony III delivers a nominal heat output of 12kW, making it an excellent choice for larger homes and living spaces with greater heating demands. It comfortably heats areas of up to 420m³, making it particularly well suited to spacious lounges, open-plan layouts, and period properties.
With an efficiency rating of 76%, the stove maximises heat from every load of fuel while reducing unnecessary waste. It also gives homeowners the flexibility to burn either wood or approved smokeless fuel, allowing them to adapt to seasonal preferences and fuel availability without changing appliances.
Nestor Martin Harmony III Multi Fuel Stove Advanced Combustion Technology
Although the Harmony III retains its traditional appearance, it incorporates modern technology that improves everyday performance.
A built-in thermostatic damper automatically regulates combustion to help maintain a comfortable and consistent room temperature. Adjustable air controls work alongside the damper, allowing you to fine-tune the burn rate for different fuel types and heating requirements.
Nestor Martin also equips the stove with its direct draught system, which encourages efficient flue draw during lighting to establish the fire more quickly. Once the fire is established, the integrated airwash system directs airflow across the glass to help keep the viewing window cleaner, giving you a clearer view of the flames with less frequent cleaning.
Eco-Design Compliant Installation
The Harmony III meets current Eco-Design standards, delivering lower emissions while maintaining the powerful heating performance expected from a premium multi-fuel stove. Its A Energy Rating reflects its efficient operation, making it a responsible choice for homeowners who want to combine traditional heating with modern environmental standards.
The stove measures 732mm high, 740mm wide, and 469mm deep, with a robust cast iron construction and an overall weight of 200kg. During installation, maintain a clearance of 400mm from combustible materials at both the rear and sides. The centre of the top flue outlet sits 194mm from the rear of the stove, while the rear flue outlet centre sits 554mm above the base, giving installers the information they need to plan the flue configuration accurately.
If you’re planning a new appliance, understanding the wood-burning stove installation process can help you position the stove correctly and achieve the best possible performance. We also recommend professional stove installation to ensure safe, efficient operation and compliance with current building regulations.
Nestor Martin Harmony III Multi Fuel Stove Built for Lasting Performance
The Nestor Martin Harmony III Multi Fuel Stove offers an outstanding combination of traditional craftsmanship, fuel flexibility, and dependable heating performance. Its durable cast iron construction, thermostatic combustion controls, side-loading convenience, and Eco-Design compliant technology work together to deliver a premium stove that combines lasting character with everyday capability.
To find out more about what a professional installation involves, visit our installation process page. For full technical documentation directly from the manufacturer, visit the official Nestor Martin product pages for the Nestor Martin Harmony III Multi Fuel Stove.
Nestor Martin Harmony III Multi Fuel Stove — Technical Specifications
Core Specifications
| Specification | Detail |
|---|---|
| Brand | Nestor Martin |
| Model | Harmony III |
| Fuel Type | Multi-Fuel (Wood & Approved Smokeless Fuel) |
| Construction | Full Cast Iron |
| Energy Efficiency Rating | A |
| Efficiency | 76% |
| Nominal Heat Output | 12kW |
| Recommended Heating Area | Up to 420m³ |
| Maximum Log Length | 500mm |
| CO Emissions (13% O₂) | 0.09% |
| Thermostatic Damper | Yes |
| Airwash System | Yes |
| Direct Draught Slide | Yes |
| Side Loading Door | Yes |
| EcoDesign Compliant | Yes |
| Standard | EN 13240 |
| Dimensions | See Dimensional Download Below |
Dimensions
| Specification | Measurement |
|---|---|
| Height | 732mm |
| Width | 740mm |
| Depth | 469mm |
| Distance to Centre of Top Flue Outlet (from Rear) | 194mm |
| Height to Centre of Rear Flue Outlet | 554mm |
Weight
| Specification | Measurement |
|---|---|
| Weight | 200kg |
Installation Clearances
| Specification | Requirement |
|---|---|
| Rear Clearance to Combustible Materials | 400mm |
| Side Clearance to Combustible Materials | 400mm |
Downloads
| Harmony 1 & 3, 7100DA001_1.pdf |
| Harmony III Energy Label.pdf |
| Harmony III Fiche.pdf |
| NM_Harmony 1 & 3 03 2024 UK.pdf |
| IN1188 Servicing Stanford 80 Harmony 1 and 3 2020.pdf |











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