Underfloor Heating Output Calculator
W/m² a wet UFH floor can emit from floor surface and room temperatures.
The 29 °C comfort cap limits UFH to ~100 W/m² — fine for insulated homes, not enough for leaky ones. Floor coverings (rugs!) eat output.
Formula
Underfloor Heating Output Calculator is a free underfloor heating 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 Underfloor Heating Output Calculator
W/m² a wet UFH floor can emit from floor surface and room temperatures. The calculation implements q = 8.92·(T_floor − T_room)^1.1 (EN 1264) (EN 1264 — water-based surface heating). The 29 °C comfort cap limits UFH to ~100 W/m² — fine for insulated homes, not enough for leaky ones. Floor coverings (rugs!) eat output.
How to use Underfloor Heating Output Calculator
- 1Enter Mean floor surface temp in °C (Max 29 °C occupied · 33 °C bathrooms (EN 1264)).
- 2Enter Room temperature in °C.
- 3Enter Heated floor area in m².
- 4Read Specific output, Room total instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Underfloor Heating Output Calculator?
- ✓Implements the standard formula — q = 8.92·(T_floor − T_room)^1.1 (EN 1264)
- ✓Reference cited on-page: EN 1264 — water-based surface heating
- ✓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 Underfloor Heating Output Calculator use?+
It computes q = 8.92·(T_floor − T_room)^1.1 (EN 1264), per EN 1264 — water-based surface heating. 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?+
The 29 °C comfort cap limits UFH to ~100 W/m² — fine for insulated homes, not enough for leaky ones. Floor coverings (rugs!) eat output.
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 Underfloor Heating Output Calculator 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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