Finnleo Karhu 20 Home (282-702 cu ft) Wood-Burning Sauna Stove

Finnleo Karhu 20 Home (282–702 cu ft) Wood-Burning Sauna Stove

The Finnleo Karhu 20 Home is a classic, chrome-accented wood-burning sauna stove built for authentic, wood-fired Finnish sauna bathing. Manufactured under the Kastor Karhu line and CE-marked for safety and performance, the Karhu 20 Home combines a compact floor footprint with intelligent combustion engineering that delivers maximum heating power from minimal wood consumption. Its stylish design and chrome front panel are engineered to complement any sauna interior, while its impressive heat storage properties keep the sauna warm long after the fire has died down.

Sized for sauna rooms between 282 and 702 cubic feet, the Karhu 20 Home is ideal for traditional home saunas that want the genuine ritual, aroma, and radiant heat of a real wood fire rather than an electric heater. All Kastor Karhu heaters feature adjustable legs for level installation on a variety of floor types, and use a 115 mm flue for chimney connection.

Key Features

• Genuine wood-burning heater with CE certification
• Chrome front panel and stylish, sauna-friendly design
• Heats sauna rooms from 282 to 702 cubic feet
• 70 lb (approx. 35–40 kg) stone/rock capacity
• Compact floor-standing footprint, minimal space required
• Adjustable legs for stable, level installation
• 115 mm flue connection (rear or top connection options)
• Deep stone compartment with Coanda-style air circulation for even, efficient heat transfer to the rocks
• Ceram fire-door glass rated to withstand 800°C while showcasing the visible flame
• Built from Finnish structural steel for durability and heat resistance

Construction & Design

The Karhu 20 Home is constructed from high-grade Finnish structural steel, chosen for its uniform quality, strength retention under heat, and long-term durability. The fire door uses a special Ceram heat-resistant glass capable of withstanding temperatures up to 800°C, allowing bathers to enjoy the warm glow of the live flame safely. Internally, the heater uses a Coanda air circulation system paired with a large, deep stone compartment, allowing hot combustion gases to flow freely between the rocks for fast, even heating and excellent heat retention. This design lets the stove keep radiating comforting heat well after the fire itself has burned down.

Heating Performance

With a nominal output of approximately 12 kW and a flue draft optimized around -12 Pa, the Karhu 20 Home is engineered to bring a sauna up to bathing temperature in roughly 40–50 minutes on a single loaded batch of wood, with no need to add more fuel for a typical bathing session. For longer sessions or colder conditions, additional wood batches can be stoked once the prior batch has burned to embers. The heater achieves roughly 72% combustion efficiency and is designed to burn cleanly using properly seasoned, unprocessed firewood (birch or alder recommended, 12–20% moisture, pieces up to approximately 35 cm in length).

Rocks & Heat Retention

The Karhu 20 Home holds approximately 70 lbs (35–40 kg) of sauna stones. Peridotite or dunite stones at least 10 cm in diameter are recommended, placed loosely and vertically within the deep stone compartment to allow hot flue gases to pass freely between them. Proper stone placement and quantity are essential — packing stones too tightly, using stones that are too small, or under-filling the compartment will prevent the rocks from reaching proper bathing temperature even if the surrounding air heats quickly.

Optional Accessories

• Piped water tank (for supplemental hot water)
• Protective wall (for reduced side/back safety clearances)
• Protective base (required for installation on flammable flooring)

What's Included

• Karhu 20 Home wood-burning sauna heater
• Grate
• Connection pipe (for flue installation)
• Door handle with mounting screw and nuts
• Two steel caps (for the stone compartment soot hatch and the unused flue opening)
• Ash pan
• Installation and user instructions

Note: Sauna stones, chimney/flue components, and the optional water tank, protective wall, or protective base are sold separately unless otherwise specified by your dealer.

Technical Specifications

• Sauna Size: 282–702 cu. ft.
• Nominal Output: approx. 12 kW
• Stone Capacity: 70 lbs (35–40 kg)
• Dimensions (W x H x D): 17" x 28.75" x 18"
• Flue Diameter: 115 mm
• Installation Type: Floor-standing, adjustable legs
• Fuel Type: Unprocessed firewood (birch or alder recommended)
• Certification: CE-marked
• Warranty: 2-year Sauna360 factory warranty against manufacturing defects

Why Buy Finnleo From Us

Finnleo, built by Sauna360, is one of the most trusted names in authentic Finnish sauna. Every Karhu wood-burning heater is CE-certified and backed by a full Sauna360 factory warranty. As an authorized Finnleo dealer, we offer expert sizing help, genuine factory-backed products, and support before and after your purchase. Have questions about sauna room sizing, chimney installation, or accessory compatibility? Reach out and a sauna specialist will help you get it right the first time.