Radiator BTU Output by Size and Type
Reference table of radiator BTU and watt outputs for single panel, double panel, and column radiators at standard Delta T 50 conditions.
Type 11 (Single Panel, Single Convector) at ΔT50
| Length (mm) | 400 mm high | 500 mm high | 600 mm high | 700 mm high |
|---|---|---|---|---|
| 600 | 382 W / 1,303 BTU | 478 W / 1,631 BTU | 574 W / 1,959 BTU | 669 W / 2,283 BTU |
| 800 | 509 W / 1,737 BTU | 637 W / 2,174 BTU | 765 W / 2,611 BTU | 893 W / 3,047 BTU |
| 1000 | 637 W / 2,174 BTU | 796 W / 2,717 BTU | 956 W / 3,262 BTU | 1,115 W / 3,804 BTU |
| 1200 | 764 W / 2,607 BTU | 955 W / 3,260 BTU | 1,147 W / 3,914 BTU | 1,338 W / 4,565 BTU |
| 1400 | 891 W / 3,041 BTU | 1,115 W / 3,804 BTU | 1,338 W / 4,565 BTU | 1,561 W / 5,327 BTU |
Type 22 (Double Panel, Double Convector) at ΔT50
| Length (mm) | 400 mm high | 500 mm high | 600 mm high | 700 mm high |
|---|---|---|---|---|
| 600 | 644 W / 2,198 BTU | 818 W / 2,792 BTU | 993 W / 3,389 BTU | 1,168 W / 3,986 BTU |
| 800 | 859 W / 2,931 BTU | 1,091 W / 3,723 BTU | 1,324 W / 4,518 BTU | 1,557 W / 5,313 BTU |
| 1000 | 1,074 W / 3,665 BTU | 1,364 W / 4,654 BTU | 1,655 W / 5,649 BTU | 1,946 W / 6,640 BTU |
| 1200 | 1,289 W / 4,399 BTU | 1,637 W / 5,586 BTU | 1,986 W / 6,778 BTU | 2,335 W / 7,967 BTU |
| 1400 | 1,503 W / 5,129 BTU | 1,909 W / 6,515 BTU | 2,317 W / 7,907 BTU | 2,724 W / 9,295 BTU |
Heat Pump Correction Factors
| Flow/Return Temp | ΔT | Output Factor | System Type |
|---|---|---|---|
| 80/60°C | ΔT50 | 1.00 (100%) | Standard gas boiler |
| 70/50°C | ΔT40 | 0.75 (75%) | Condensing boiler (optimised) |
| 55/45°C | ΔT30 | 0.52 (52%) | High-temp heat pump |
| 45/35°C | ΔT20 | 0.30 (30%) | Low-temp heat pump |
Related Calculators
Use the Radiator Sizing Calculator for room-by-room sizing, or the Heat Loss Calculator for accurate heat demand. The BTU Calculator provides quick room estimates.
How We Calculate This
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.