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BTU Calculator - Easily Find the Right Size Radiator
Finding the right radiator size ensures your room stays warm, efficient, and comfortable. Radiator heat output is measured in British Thermal Units (BTU), and every room has unique heating needs depending on its size, use, and insulation.
Our calculator uses typical UK heat loss rates and provides both BTU and watt outputs based on your room dimensions and insulation level.
How the Calculator Works
- We calculate room volume from your dimensions (Length × Width × Height).
- We apply a calibrated heat loss rate based on room usage.
- We adjust for insulation quality.
- Finally, we convert to BTU (Watts × 3.412).
Calculate the recommended heat output for your room.
2.4m = UK Typical Height
*Results are a guide. For exact requirements, consult a heating professional.