Heating Load Guide
A practical overview of early-stage room heat loss estimation for HVAC design.
What matters most
Heating load is mainly driven by room size, envelope quality, temperature difference, orientation, and glazing. For quick screening, the calculator combines wall loss, window loss, and infiltration loss into one estimate.
Common mistakes
- Using nominal rather than actual window U-values.
- Ignoring infiltration in older or leakier buildings.
- Treating an estimate as a final design load.
When to use the calculator
Use it at concept stage, during equipment screening, or when comparing room loads quickly.