KAWMET Premium HERMES F23 (14 kW) Fireplace Insert
KAWMET Premium HERMES F23 (14 kW) is a wood-burning fireplace insert from the Polish foundry KAWMET with a nominal output of 14 kW, sized for rooms of up to 120 m² (up to 300 m³). A flat front pane shows the firebed head-on. Thermal efficiency is 78.6 %, energy class A.
The body weighing 120 kg is cast entirely from iron. Unlike steel constructions, cast iron does not warp under high temperature and stores heat — releasing it long after the fire has burnt down. Closely spaced fins enlarge the heat exchange surface, and a vermiculite baffle extends the path of the flue gases, so more energy stays in the room instead of escaping up the chimney.
Key features — HERMES F23
- Nominal output 14 kW — heats up to 120 m² (300 m³)
- Thermal efficiency 78.6 %, energy class A
- Secondary combustion — secondary air burns off gases that would otherwise escape up the flue
- Clean glass system — air guided along the pane limits soot build-up
- Heat-resistant Robax ceramic pane — withstands temperatures up to 800 °C
- Built-in baffle extending the path of the flue gases above the firebed
- Air supply adjusted through the ash pan
- Provision for an external combustion air supply
- Flue outlet top, flue pipe Ø200 mm; door opens to the left
- Maximum log length 600 mm
- Dimensions (W × H × D): 750 × 587 × 467 mm, weight 120 kg
- Material: cast iron. Made in Poland — 5-year warranty
The KAWMET Premium range — cast iron and design
The KAWMET Premium line covers inserts where the look of the casting matters as much as the output. The insert is cast from premium-grade iron with increased thermal conductivity — the manufacturer states this translates into roughly 30 % better heat conduction than standard cast iron, with a matching reduction in wood consumption.
The pane is made of heat-resistant Robax ceramic glass rated to 800 °C. A built-in baffle extends the path of the flue gases above the firebed, and the air supply is adjusted with a single movement — through the ash pan.
Is 14 kW enough to heat my house?
The model is rated for roughly 120 m² with standard insulation and a ceiling height of 2.5–2.7 m. In a poorly insulated building, one with large glazed areas or a higher ceiling, the real figure will be lower. Oversizing is harmful too, however: for most of the season the appliance then runs on a low flame, which soots up the glass and the flue faster.
Does it need an external air supply?
The model is designed for it, and in an airtight building with mechanical ventilation or heat recovery it is the recommended solution — without its own air supply, ventilation can reverse the flue draught. In an older building with natural ventilation an external air supply is not essential, but it usually makes combustion more stable. The connection parts (inlet, orifice, pipe) are ordered separately — they are not part of the set.
What surround and chimney does the insert require?
The insert connects to a flue of Ø200 mm, with the outlet at the top. The body measures 750 × 587 × 467 mm (W × H × D) and weighs 120 kg — the surround is designed with allowance for expansion and convection ducts, and the floor beneath the fireplace has to carry that weight. Required clearances to combustible materials and the ventilation rules for the surround are given in the manufacturer's manual, available in the documents section on this page.
What fuel should be used?
The fuel is seasoned hardwood with a moisture content of up to 20 %. The maximum log length is 600 mm. Wet wood gives noticeably less heat, smokes up the glass and speeds up soot deposits in the flue. Chipboard, painted or impregnated timber and waste must not be burnt — they shorten the life of the cast iron and void the warranty.
KAWMET products carry a 5-year manufacturer's warranty. Your nearest representative will confirm availability and purchase terms.
