Radiator Output Calculator (ΔT Correction)
Real heat output of a radiator at your actual water/room ΔT versus the ΔT50 catalogue rating.
Heat-pump flow temps (40–50 °C) cut radiator output 40–60% versus boiler-era ΔT50 ratings — the single most common retrofit miscalculation.
Formula
Radiator Output Calculator (ΔT Correction) is a free radiator output for HVAC designers, technicians and energy auditors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Radiator Output Calculator (ΔT Correction)
Real heat output of a radiator at your actual water/room ΔT versus the ΔT50 catalogue rating. The calculation implements Q = Q₅₀ × (ΔT/50)^1.3 (EN 442 — radiator rating standard). Heat-pump flow temps (40–50 °C) cut radiator output 40–60% versus boiler-era ΔT50 ratings — the single most common retrofit miscalculation.
How to use Radiator Output Calculator (ΔT Correction)
- 1Enter Catalogue output at ΔT50 in W.
- 2Enter Flow temperature in °C.
- 3Enter Return temperature in °C.
- 4Enter Room temperature in °C.
- 5Read Actual ΔT, Actual output instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Radiator Output Calculator (ΔT Correction)?
- ✓Implements the standard formula — Q = Q₅₀ × (ΔT/50)^1.3
- ✓Reference cited on-page: EN 442 — radiator rating standard
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Radiator Output Calculator (ΔT Correction) use?+
It computes Q = Q₅₀ × (ΔT/50)^1.3, per EN 442 — radiator rating standard. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Heat-pump flow temps (40–50 °C) cut radiator output 40–60% versus boiler-era ΔT50 ratings — the single most common retrofit miscalculation.
Is this based on ASHRAE methods?+
The calculations follow the standard ASHRAE/ISHRAE formulations cited under the result, simplified where industry practice does the same. For permit-grade design, confirm with the full code procedure.
Is the Radiator Output Calculator (ΔT Correction) free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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