Radiant Panel Sizing Calculator

Instantly size radiant panels for healthier winter growth. Balance output, coverage, and water flow easily. Use standard modules, then download CSV or PDF files.

Calculator Inputs
Use the form below, then press Submit.
Switching units updates input fields.
Typical insulated greenhouse: 60–120 W/m².
Covers wind, leakage, and cold snaps.
How much surface you plan to cover.
Reset
Example Data Table
Sample scenarios to compare sizing outcomes.
Scenario Area (m²) Load (W/m²) Safety Panel type Supply/Return (°C) Required area (m²) Modules (0.6×1.2)
Insulated hobby greenhouse 20 70 1.10 Standard 45/35 ~11.6 ~17
Drafty tunnel house 60 110 1.25 High-output 50/40 ~43.4 ~61
Propagation room zone 12 90 1.15 Low-temp 40/32 ~12.5 ~18
These examples are illustrative. Always verify with local design conditions.
Formula Used
Core equations behind the sizing outputs.
  • Design heat load (W):
    Area × heat load per area × safety factor
    Q = A × q × SF
  • Required panel area (m²):
    Design heat load ÷ adjusted panel output
    Ap = Q ÷ pout
  • Module count:
    Required area ÷ module area, then rounding
    N = round(Ap ÷ Am)
  • Water flow (L/min):
    Uses water heat capacity and supply-return drop
    Flow = (Q ÷ (4186 × ΔT)) × 60
How to Use This Calculator
A practical workflow for greenhouse heating.
  1. Measure your heated greenhouse area or zone area.
  2. Enter a realistic heat load for your insulation level.
  3. Set a safety factor for wind and cold snaps.
  4. Choose a panel type and water temperatures.
  5. Pick a module size to estimate panel count.
  6. Press Submit to show results above.
  7. Use Download CSV or Download PDF for sharing.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.