The most important factor is heat output, measured in kilowatts (kW). A simple formula: measure your room in cubic metres (Length × Width × Height) and divide by 14 for a well-insulated modern home, or by 10–12 for older properties.For most standard UK living rooms, a 4–5kW stove is an excellent choice — it provides comfortable heat without overwhelming the space. Remember: bigger is not better. An oversized stove forced to run at low temperatures will cause black glass, soot build-up, and inefficient burning.