In 2025, Taiwan officially launched its carbon fee trial declaration, with collection beginning in 2026 -- meaning greenhouse gas emissions have shifted from an "environmental issue" to a "financial cost." For HVAC engineering, the impact of the carbon fee is twofold: HVAC systems account for 40-60% of building energy consumption as major carbon emitters; but simultaneously, HVAC energy-saving improvements are the engineering measure with the most significant carbon reduction benefits. This article constructs a complete analytical framework from carbon inventory to investment decisions from an engineering consultant's perspective.

1. Overview of Taiwan's Carbon Fee System

According to the Climate Change Response Act and the carbon fee sub-regulations announced by the Ministry of Environment[1], Taiwan's carbon fee system implementation timeline is as follows:

  • 2024: Completed carbon fee rate review, confirmed general rate and preferential rate framework
  • 2025: Carbon fee trial declaration year, approximately 500 enterprises with annual emissions of 25,000 tons CO2e or more as first-wave regulated entities
  • 2026: Official carbon fee collection begins, general rate of NT$300 per ton CO2e
  • Subsequent years: Rates will gradually increase, aligned with emission reduction progress and international carbon prices

The Carbon Fee Rate Review Committee has clearly indicated that NT$300/ton is only the starting price[2]. Referencing the EU Carbon Border Adjustment Mechanism (CBAM) and international carbon price trends, the possibility of future rate increases to NT$500-1,000/ton is very high. This means the carbon fee is not a one-time cost shock but a continuously increasing long-term financial pressure.

Notably, even if an enterprise is not on the first-wave list of 500 regulated entities, the impact of the carbon fee will be transmitted downstream through the supply chain. Increased carbon costs for large manufacturers will drive carbon emission management throughout the entire supply chain -- which is why organizations of all sizes need to start paying attention to their HVAC system carbon emissions.

2. The Role of HVAC Systems in Carbon Emissions

HVAC Share of Building Energy Consumption

According to statistics from Taiwan's Bureau of Energy, HVAC systems in commercial buildings account for 40-60% of total electricity consumption[3]. In southern regions such as Kaohsiung, due to the high-temperature, long-sunshine climate characteristics, the HVAC share in some buildings exceeds 65%. This means HVAC systems are the single largest source of building carbon emissions and the greatest leverage point for carbon reduction.

Direct vs. Indirect Emissions

HVAC system carbon emission sources can be divided into two categories:

  • Direct emissions (Scope 1) -- Refrigerant fugitive emissions: The greenhouse effect of refrigerant leaking into the atmosphere. Using R-410A (GWP = 2,088) as an example[4], a system containing 50 kg of refrigerant with an annual leakage rate of 5% emits 2.5 kg of refrigerant per year, equivalent to 5,220 kgCO2e (approximately 5.2 tons CO2e). R-22 (GWP = 1,810) and R-134a (GWP = 1,430) similarly have high global warming potential.
  • Indirect emissions (Scope 2) -- Electricity carbon emissions: Carbon emissions corresponding to electricity consumed by HVAC system operation. Using Taiwan's 2024 electricity emission factor of approximately 0.494 kgCO2e/kWh[5], an HVAC system consuming 1 million kWh annually has annual carbon emissions of approximately 494 tons CO2e.

Carbon Emission Intensity of Cold Storage and Cold Chain Systems

Cold storage warehousing and cold chain logistics systems have carbon emission intensities far higher than general HVAC. Low-temperature cold storage systems (-25 deg C and below) have per-unit-area energy consumption 3-5 times that of general office HVAC, and cold storage systems typically use large quantities of high-GWP refrigerants (such as R-404A, GWP = 3,922), making refrigerant fugitive carbon emissions even more significant. The carbon fee system's financial impact on such high-carbon-intensity systems is particularly severe.

3. HVAC System Carbon Inventory Methods

Carbon inventory is the prerequisite for carbon fee calculation. According to the GHG Protocol[6] and ISO 14064-1[7] frameworks, HVAC system carbon inventory covers the following scopes:

Scope 1: Refrigerant Fugitive Emission Calculation

The refrigerant fugitive carbon emission formula is:

Refrigerant fugitive emissions (tCO2e) = Refrigerant charge (kg) × Annual leakage rate (%) × Refrigerant GWP ÷ 1,000

Annual leakage rates vary by equipment type and maintenance condition. IPCC default values are: commercial HVAC 2-6%, industrial refrigeration 7-15%, transport refrigeration 15-25%[4]. In practice, well-maintained systems can be controlled to 2-3%, but aging equipment often exceeds 10%.

Scope 2: Purchased Electricity Indirect Emissions

The electricity carbon emission formula is:

Electricity carbon emissions (tCO2e) = Annual electricity consumption (kWh) × Electricity emission factor (kgCO2e/kWh) ÷ 1,000

Taiwan's electricity emission factor is published annually by Taipower[5], approximately 0.494-0.509 kgCO2e/kWh in recent years. As the share of renewable energy increases, this factor will gradually decrease, but short-term fluctuations are limited.

Case Study: Annual Carbon Emissions of a 100RT Chilled Water System

Assumptions: chiller COP 4.0, 2,000 equivalent full-load operating hours per year, R-410A refrigerant charge 80 kg, annual leakage rate 5%.

  • Scope 2 (electricity): 100 RT × 3.517 kW/RT ÷ COP 4.0 = 87.9 kW (chiller input power). Including pumps and cooling tower, total system power approximately 120 kW. Annual electricity = 120 × 2,000 = 240,000 kWh. Carbon emissions = 240,000 × 0.494 ÷ 1,000 = 118.6 tCO2e
  • Scope 1 (refrigerant): 80 kg × 5% × 2,088 ÷ 1,000 = 8.4 tCO2e
  • Total annual carbon emissions: Approximately 127 tCO2e
  • Carbon fee cost (NT$300/ton): Approximately NT$38,100/year

This is just a 100RT system. A commercial office building with 500-1,000RT HVAC capacity can face annual carbon fees of NT$190,000-380,000, and this will continue to increase as rates rise.

4. How Carbon Fees Change HVAC Investment ROI Calculations

Traditional ROI vs. Carbon Fee-Inclusive ROI Comparison

Traditional HVAC energy-saving investment payback calculations only consider electricity cost savings. But in the carbon fee era, investment benefits must include carbon fee savings:

Carbon fee-inclusive ROI annual benefit = Annual electricity savings + Annual carbon fee savings
Investment payback period = Total improvement cost ÷ Carbon fee-inclusive annual benefit

Using the previous 100RT system example, if the chiller is replaced from COP 4.0 to COP 6.5, the electricity savings rate is approximately 38%. At NT$4.5/kWh electricity rate:

  • Annual electricity savings: 240,000 × 38% = 91,200 kWh
  • Annual electricity cost savings: 91,200 × 4.5 = NT$410,400
  • Annual carbon reduction: 91,200 × 0.494 ÷ 1,000 = 45.1 tCO2e
  • Annual carbon fee savings (NT$300/ton): 45.1 × 300 = NT$13,530
  • Annual carbon fee savings (NT$500/ton, projected): 45.1 × 500 = NT$22,550

The carbon fee's impact on ROI at current rates is approximately 3-5%. But as rates increase to NT$500-1,000/ton, carbon fee savings will account for 8-15% of annual benefits, significantly shortening investment payback periods.

Carbon Fee Impact on Refrigerant Selection

The "hidden carbon cost" of high-GWP refrigerants is specifically quantified in the carbon fee era. Comparing systems of equivalent cooling capacity:

  • R-410A (GWP 2,088): 80 kg refrigerant, 5% leakage rate, annual carbon fee NT$2,520 (@NT$300/ton)
  • R-32 (GWP 675): Lower charge approximately 50 kg, 5% leakage rate, annual carbon fee NT$506
  • R-290 (GWP 3): Carbon fee virtually zero

Refrigerant carbon fee differences may seem small, but for large facilities with dozens of units, the cumulative effect is considerable. More importantly, the long-term cost curve for high-GWP refrigerants will rise sharply under escalating carbon fees.

Long-Term Cost Projections with Escalating Carbon Fees

Assuming carbon fees are adjusted upward every 2-3 years, from NT$300 gradually rising to NT$1,000/ton, a 500RT commercial HVAC system's cumulative 10-year carbon fees could increase from NT$2 million to over NT$6 million. Early implementation of energy-saving improvements effectively locks in a lower carbon cost baseline, avoiding future rate risks.

5. HVAC Improvement Measures with the Greatest Carbon Reduction Benefits

Ranked by carbon reduction cost-effectiveness, the following five measures are the most worthwhile HVAC improvement directions for priority investment:

1. Chiller Replacement

Replacing aging chillers (COP 3.5-4.0) with high-efficiency magnetic bearing or centrifugal chillers (COP 6.0-6.5) is the single improvement project with the greatest carbon reduction benefit. For a 500RT system, chiller replacement can reduce approximately 225 tCO2e annually, equivalent to carbon fee savings of NT$67,500/year (@NT$300/ton). Including electricity savings benefits, the investment payback period is approximately 5-7 years, which can be shortened to 4.5-6 years with carbon fee benefits included[8].

2. VFD Retrofit

VFD retrofits for chilled water pumps, condenser water pumps, and cooling tower fans can save 20-40% electricity. Pump power consumption is proportional to the cube of speed (affinity laws) -- reducing speed by 20% saves approximately 49% of electricity. This is the lowest-cost, fastest-payback improvement measure, typically recovering investment in 2-3 years.

3. Refrigerant Transition

Transitioning from high-GWP refrigerants (R-410A, R-404A) to low-GWP refrigerants (R-32, R-290, R-1234ze) directly reduces Scope 1 refrigerant fugitive carbon emissions. For cold storage and other systems with large refrigerant volumes, the carbon reduction benefit of refrigerant transition is particularly significant. Aligning refrigerant transition with equipment replacement schedules avoids redundant investment.

4. Heat Recovery Systems

HVAC systems discharge large amounts of waste heat to the atmosphere. Through heat recovery systems that recover condenser waste heat for hot water supply or process heating, 15-30% of redundant energy consumption can be reduced. Hotels, hospitals, food factories, and other facilities with simultaneous cooling and heating demands see the most significant carbon reduction benefits from heat recovery.

5. Smart Controls and Optimization

Implementing AI-driven optimization control strategies (such as chilled water supply temperature reset, dynamic condenser water temperature adjustment, partial-load optimal scheduling) typically achieves an additional 10-15% electricity savings without replacing major equipment. Investment costs are lower, but require good sensor deployment and data infrastructure.

Carbon Reduction Benefit Ranking of Each Measure

Using a 500RT commercial chilled water system as reference baseline, estimated annual carbon reduction for each measure:

  • Chiller replacement: 200-250 tCO2e/year (highest)
  • VFD retrofit: 80-120 tCO2e/year
  • Refrigerant transition: 20-50 tCO2e/year (depending on refrigerant type and charge)
  • Heat recovery system: 60-100 tCO2e/year (depending on heat recovery application)
  • Smart controls: 40-80 tCO2e/year

If these measures are implemented comprehensively, 40-60% overall carbon reduction can be achieved, significantly lowering carbon fee expenditure.

Need to assess your facility's HVAC carbon emissions and energy-saving improvement options? Contact our engineering team for comprehensive engineering consulting services from carbon inventory to investment benefit analysis.

6. Engineering Strategies for Carbon Credits and Preferential Rates

Preferential Rates through Voluntary Reduction Plans

The Ministry of Environment's carbon fee system includes a preferential rate mechanism[9]: if an enterprise submits an approved voluntary reduction plan and achieves reduction targets, a lower preferential rate (approximately 60-80% of the general rate) may apply. HVAC energy-saving improvement plans qualify for voluntary reduction plan applications, and enterprises can obtain preferential rate eligibility through specific equipment replacement and control optimization programs.

Carbon Credits Available for HVAC Energy Savings

Beyond carbon fee preferential rates, HVAC energy-saving improvement projects with additionality can apply for domestic carbon credits (voluntary reduction credits) based on reduction methodologies announced by the Ministry of Environment. Obtained carbon credits can be used to offset carbon fees or sold on the domestic carbon credit trading market. Common applicable methodologies in the HVAC field include: high-efficiency HVAC equipment replacement, refrigerant substitution, waste heat recovery, etc.

SBTi Science-Based Targets and HVAC Planning

An increasing number of enterprises are setting science-based emission reduction targets according to SBTi (Science Based Targets initiative)[10]. SBTi-required reduction pathways typically call for 4.2% annual linear reduction. For HVAC systems, this means developing a 5-10 year phased improvement plan: short-term (1-2 years) prioritizing VFD retrofits and control optimization, medium-term (3-5 years) completing chiller replacement, and long-term (5-10 years) achieving refrigerant transition and system redesign. Aligning HVAC improvement plans with SBTi targets not only fulfills emission reduction commitments but systematically reduces carbon fee expenditure.

Conclusion

The carbon fee era has changed the fundamental logic of HVAC engineering investment decisions. The decision variables of the past were "electricity cost vs. equipment cost"; now, "carbon fee cost vs. carbon reduction benefit" must be added. This is not adding one variable but an upgrade of the entire decision framework. For HVAC engineering consultants, carbon inventory capability, carbon fee cost modeling, and carbon credit strategy planning will become core competencies equal in importance to cooling tonnage calculations and equipment selection. Future HVAC engineering planning reports will no longer contain only cooling capacity and energy efficiency ratios -- carbon emission volumes and carbon cost projections will be standard chapters in every report.