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Radiator Size Finder
Ctrl+D to bookmark this toolEstimate room heat loss from area and room type, then find matching radiators by output rating. Free, instant results.
Estimated heat loss
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Room area
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Heat loss rate
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Formula: Heat loss (W) = Area (m²) × Rate (W/m²)
Indicative rates for typical UK dwellings. Not a substitute for a full heat loss calculation per BS EN 12831.
Required output
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In kW
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Typical heat loss rates by room type
Indicative values for UK dwellings with reasonable insulation. Actual heat loss depends on U-values, glazing, exposure, and ventilation.
| Room type | Rate (W/m²) | Notes |
|---|---|---|
| Living room | 65 | External walls, typical glazing |
| Bedroom | 60 | Standard insulation |
| Kitchen | 80 | Higher ventilation requirement |
| Bathroom | 70 | Higher target temperature |
| Hallway | 55 | Internal space, lower losses |
| Dining room | 75 | Similar to living room |
| Conservatory | 85 | High glazing ratio |
MEP Desk includes full room-level heat loss calculations with fabric and ventilation losses, linked to real radiator data and project schedules.