The OGNIWO BIO heating boiler is an innovative device created by the SMO OGNIWO brand, meeting the stringent requirements of the PN-EN 303-5:2021-09 standard for Class 5. Thanks to modern technology, the boiler recovers over 90% of energy from firewood and other biofuels, making it one of the most efficient and economical heating devices on the market.
The OGNIWO BIO boiler meets the Class 5 requirements and the Ecodesign Directive for both firewood and pellets. This means it is environmentally friendly, producing minimal emissions of harmful substances.
This boiler is an excellent solution for those looking for a modern, flexible, and economical heat source. It is perfect for single-family homes, small businesses, or farms where heating efficiency and ease of use are essential.
With OGNIWO BIO, you don’t have to choose just one fuel – the flexibility of the device allows you to adapt the heating system to your current needs. It’s comfort, savings, and environmental care in one device!

| Parameters | Unit | OGNIWO BIO 6 Boiler | OGNIWO BIO 8 Boiler | OGNIWO BIO 12 Boiler | OGNIWO BIO 18 Boiler | OGNIWO BIO 25 Boiler |
|---|---|---|---|---|---|---|
| Nominal Power | kW | 6 | 8 | 12 | 18 | 25 |
| Water Jacket Heating Surface | m² | 1.2 | 1.8 | 2.3 | 2.6 | 3.2 |
| Fuel Chamber Capacity | l | 34 | 42 | 52 | 64 | 94 |
| Boiler Water Capacity | l | 38 | 50 | 65 | 81 | 98 |
| Recommended Minimum Buffer Tank Volume | l | 300 | 300 | 450 | 600 | 850 |
| Maximum Operating Pressure | bar | 2 | 2 | 2 | 2 | 2 |
| Housing Dimensions (width x depth x height) | mm x mm x mm | 400 x 620 x 985 | 400 x 620 x 1060 | 400 x 685 x 1190 | 400 x 730 x 1245 | 520 x 730 x 1260 |
| Boiler Weight | kg | 220 | 265 | 285 | 337 | 370 |
| Outlet and Return Thread | inch | G1 ½ | G1 ½ | G1 ½ | G1 ½ | G1 ½ |
| Required Chimney Draft | Pa | 20 | 20 | 20 | 20 | 20 |
| Minimum Chimney Cross-Section | cm x cm / Ø mm | 18 x 18 / 180 | 18 x 18 / 180 | 18 x 18 / 180 | 20 x 20 / 180 | 20 x 20 / 200 |
| Loading Door Opening Dimensions (width x height) | mm x mm | 203 x 188 | 205 x 250 | 205 x 250 | 205 x 250 | 300 x 250 |
| Combustion Chamber Dimensions (depth x width x height) | mm x mm x mm | 340 x 275 x 360 | 340 x 275 x 420 | 380 x 275 x 510 | 420 x 275 x 555 | 420 x 400 x 555 |
| Flue Pipe Diameter | mm | 140 | 140 | 160 | 160 | 160 |
| Approximate Usable Building Area | m² | up to 100* | up to 120* | up to 160* | up to 220* | up to 300* |
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