HVAC Standards Comparison
Side-by-side comparison of the three major international HVAC design standards: ASHRAE (US/International), GB 50736 (China), and SHASE (Japan). Understand the key differences in design outdoor temperatures, insulation classifications, safety factors, and calculation methodologies for heating load, cooling load, duct sizing, and radiator sizing.
Heating Load: ASHRAE vs GB vs SHASE
Compare design outdoor temperatures, indoor setpoints, infiltration models (0.35 ACH vs 0.5 h⁻¹ vs C-value), orientation corrections, and safety margins across the three standards. See which standard gives the most conservative result.
Cooling Load: ASHRAE vs GB vs SHASE
Compare unit-index cooling load approaches: ASHRAE's CLTD/CLF method, GB 50736's simplified index (80-160 W/m²), and SHASE-S 112's heat load per unit floor area (60-160 W/m²).
Duct Sizing: ASHRAE vs GB vs SHASE
Comparison of duct velocity limits, friction rate targets, aspect ratio guidelines, and material specifications per ASHRAE/SMACNA, GB 50736, and SHASE-S 010.
Radiator Sizing: EN 442 vs GB/T 13754
Compare the European EN 442 standard (ΔT50 nominal output, exponent-based correction) with China's GB/T 13754 (standard conditions at 95/70°C and 130/70°C). Real-world correction factor comparison.
Which Standard Should You Use?
The right standard depends on your project location, client requirements, and local code compliance:
| Region | Primary Standard | Secondary Reference |
|---|---|---|
| North America | ASHRAE (90.1, RTS, SMACNA) | IECC, Title 24 (California) |
| China | GB 50736-2012 | GB/T 13754 (radiators), GB 50054 (electrical) |
| Japan | SHASE-S 101/112/010 | Building Standards Law |
| Europe | EN 12831 (heating), EN 15251 | CIBSE (UK), DIN V 18599 (Germany) |
| Middle East / SE Asia | ASHRAE (adapted) | Local municipality codes |
Key Differences at a Glance
| Parameter | ASHRAE | GB 50736 | SHASE |
|---|---|---|---|
| Design Approach | RTS / Heat Balance | Index Method (W/m²) | Unit Floor Area Method |
| Climate Zones | 8 zones (IECC) | 5 zones | 6 regions |
| Infiltration Model | 0.35 ACH (residential) | 0.5 h⁻¹ (residential) | C-value method |
| Safety Factor | 10–15% typical | 10% minimum | 10–20% (seismic) |
| Duct Velocity | 700–900 fpm (residential) | 3–5 m/s (residential) | 5–8 m/s (residential) |
| Radiator ΔT | EN 442: ΔT50 | GB/T 13754: 64.5°C | JIS-compatible |
How to Use These Comparisons
- Identify your project location — determines which standard is legally required.
- Open the relevant comparison page — each provides a detailed side-by-side table with exact parameter values.
- Enter values into our HVAC calculators — all tools support parameters from any standard. Select your preferred standard in the calculator inputs.
- Cross-reference for international projects — use comparison tables to understand value differences and choose the appropriate conservative approach.