Input Parameters
About This Calculator
- Calculates wall, window, and infiltration heat losses
- Automatically applies orientation correction factors
- Default radiator output: ~150W per section (600mm column type)
- This calculator provides an early-stage sizing estimate. Verify final HVAC design against local codes and project specifications.
How this heating load calculator works
This tool estimates room heat loss from exterior wall transmission, optional window transmission, and infiltration. It applies orientation and insulation assumptions, then reports total load, load density, and a preliminary radiator sizing estimate.
Inputs explained
- Room area and height define the heated volume and approximate exterior wall area.
- Orientation adjusts for typical winter solar exposure differences.
- Insulation level selects an approximate wall U-value for early-stage sizing.
- Outdoor and indoor design temperatures define the heating temperature difference.
- Window area and U-value add separate glazing heat loss when exterior windows are present.
FAQ
Can I use this as a final heat loss calculation?
No. It is intended for preliminary estimates. Final design should use project-specific envelope data, ventilation rates, local design weather, and applicable codes.
Why does orientation affect the result?
The calculator applies a simplified orientation factor to reflect typical winter solar exposure and envelope heat loss differences.
What does heat load density mean?
Heat load density is total heating load divided by floor area. It helps compare rooms of different sizes and identify unusually high loads.