In 2022, Taiwan passed the Climate Change Response Act, formally legislating the 2050 net-zero emission target. The building sector accounts for approximately 15% of national carbon emissions, and HVAC systems account for 40–50% of building energy consumption — meaning HVAC system decarbonization is the largest leverage point for building net-zero. As the concluding article in this series, this piece outlines the transformation pathway for HVAC engineering in the net-zero era, from carbon inventory to decarbonization strategies.

Building Energy Efficiency New Era Series
  1. EEWH Green Building Label HVAC Energy Efficiency Indicators
  2. 2026 Commercial Energy Efficiency Subsidy Complete Guide
  3. ESCO Energy Performance Contracting
  4. 2050 Net-Zero Building Pathway and HVAC Decarbonization (This Article)

1. Building Energy Efficiency Rating System

The Building Energy Efficiency Rating System (BERS) promoted by the Ministry of the Interior[1] classifies building energy efficiency from Grade 1 to Grade 7 (Grade 1 being the best), plus "Near-Zero Carbon Building" (Grade 1+). This rating system will be progressively incorporated into mandatory building code requirements:

  • From 2026: New public buildings must achieve Energy Efficiency Grade 1 or Near-Zero Carbon
  • Before 2030: All new buildings must achieve a specified energy efficiency grade
  • Before 2040: 50% of existing buildings complete energy efficiency improvements
  • 2050: All buildings achieve net-zero carbon emissions

HVAC system efficiency directly affects building energy efficiency ratings. Upgrading from Grade 7 to Grade 1 typically requires HVAC systems to transition from traditional fixed-speed systems to high-efficiency variable-speed equipment with smart controls.

2. Carbon Inventory for HVAC Systems

Carbon emission sources from HVAC systems can be divided into two major categories[2]:

Energy Consumption Carbon Emissions (Scope 2)

Carbon emissions corresponding to electricity consumed by HVAC system operations. Using Taiwan's 2025 grid emission factor of approximately 0.495 kgCO₂e/kWh, a mid-size office building HVAC system consuming 5 million kWh annually produces approximately 2,475 tonnes CO₂e per year. Reducing energy consumption (improving COP, optimizing controls) is the direct means of reducing this type of carbon emission.

Refrigerant Fugitive Emissions (Scope 1)

The Global Warming Potential (GWP) of refrigerants is an easily overlooked component of HVAC carbon inventory. R-410A has a GWP of 2,088 (equivalent to 2,088 times CO₂), meaning even small leakages produce significant carbon emission equivalents. This is also the core driver behind the global acceleration to transition from high-GWP refrigerants to low-GWP alternatives (such as R-32 GWP=675, R-290 GWP=3)[3].

3. Five Key HVAC Decarbonization Strategies

  • Reduce Cooling Demand: Improve building envelope insulation, shading design, and high-efficiency lighting (reduce internal heat gains), addressing HVAC loads at the source
  • Improve Equipment Efficiency: Adopt high-IPLV chillers, magnetic bearing compressors, and high-efficiency VRF systems to reduce electricity consumption per refrigeration ton
  • Smart Control Optimization: Implement AI-driven optimization controls (as explored in this website's AI HVAC series), enabling systems to operate efficiently even under part-load conditions
  • Low-GWP Refrigerant Transition: Prioritize equipment using R-32 or natural refrigerants during equipment replacement to reduce fugitive refrigerant carbon emissions
  • Renewable Energy Integration: Combine rooftop solar power generation with battery/ice storage systems to increase the proportion of on-site green energy consumption[4]

4. The Role of Heat Pump Technology in Net-Zero

Heat pumps are the only technology within HVAC systems that can simultaneously provide cooling and heating, with heating-mode COP reaching 3–5, far superior to electric heating or gas boilers. In net-zero buildings, air-source and ground-source heat pump applications will be upgraded from "optional solution" to "preferred solution"[5]. Taiwan's climate conditions favor year-round air-source heat pump operation, particularly in hotels, hospitals, and other buildings with simultaneous cooling and hot water demands, where heat pump heat recovery benefits are significant.

5. Building Net-Zero Competencies for HVAC Engineers

The net-zero era places new capability requirements on HVAC engineers:

  • Carbon Inventory Capability: Understanding ISO 14064 greenhouse gas inventory standards and calculating HVAC system carbon emissions
  • Whole-Life Carbon Analysis: Carbon footprint assessment across the entire lifecycle from equipment manufacturing, transportation, installation, operation, to decommissioning
  • Regulatory Tracking: Closely following regulatory developments in building energy efficiency ratings, carbon fee collection, and refrigerant controls
  • Cross-System Integration: HVAC is no longer a standalone system — it requires integrated design with electrical, renewable energy, and energy storage systems

Conclusion

From EEWH green building labels, energy efficiency subsidies, ESCO performance contracting to the 2050 net-zero pathway — this four-article series depicts the policy evolution of building energy efficiency from "voluntary" to "mandatory" and from "energy saving" to "net-zero." HVAC engineers stand at the core of this transformation: every design decision, every equipment selection, and every control strategy determines a building's carbon emission trajectory for decades to come. This is not merely a technical challenge — it is a generational responsibility.