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Heat gain — Roof & Floor
Heat gain step 5 — ceiling/attic and floor/slab on one screen.
- Ceiling / attic: area, R-value, attic type, and hot-day attic temperature (can exceed 50°C).
- Floor / slab: floor area and R-value for the ground/crawl path.
- Positive ceiling and floor areas are part of the minimum data needed to run Results (with all four wall areas).
Disclaimer: Simplified residential estimate — not full Manual J / ACCA certification.