1. Cooling-load baseline
We start from an empirical volume formula published in TVTC training material: length × width × height × 300 BTU/h. It is an approximate starting point, not a building-design standard.
2. Condition adjustments
We apply limited factors for sun, insulation, windows and climate, plus conservative additions for internal heat, top floor and occupancy. These factors are our estimation model—not government values. Their job is to avoid relying on floor area alone, not to simulate HAP or EnergyPlus.
| Factor | Behavior |
|---|---|
| Sun | From a small reduction for shade to an increase for strong direct sun |
| Insulation | Good insulation lowers the estimate; poor insulation raises it |
| Windows | Large glazing raises the estimate |
| Top floor / heat load | An additional conservative increase |
| Occupancy | An addition beyond the first two people |
3. Uncertainty range
We turn the result into a range. The margin widens when the city is unspecified, insulation is unknown, the room is large or conditions are unusual. “Confidence” describes confidence in the estimate, not a certificate that a particular unit is correctly engineered.
4. Model-specification check
We compare the model’s Cooling Capacity with the estimated room range. If you enter Input Power, we show ratios derived only from the supplied capacity and power to help you read the specification; we do not turn them into a bill or claim an official efficiency grade. Annual energy use, if entered, is displayed exactly as copied from the model’s energy label.
5. What we do not calculate
- Measured air leakage or actual wall/glazing U-values.
- Detailed latent humidity load, air distribution or duct design.
- Compressor performance at every outdoor temperature.
- Electricity tariffs, household bills or multi-year ownership cost.