台灣為海島型國家，因自有能源貧乏，99%以上的能源仰賴國外進口。為確保能源供給之穩定與安全，除發展再生能源之外，提高能源終端使用效率為重要之解決手段。熱泵系統因其獨特之節能減碳效果，在歐美先進國家備受重視，極力推廣。基此，考量台灣氣候類型及居住型態，評估熱泵熱水系統的適用性及成本效益分析，爰為本研究之動機與目的。 為了彰顯應用熱泵系統在不同地區氣候條件與能源價格之差異，本研究將台灣劃分為12個地區，並且以電能、LPG桶裝瓦斯、NG管線瓦斯三種現有之住宅用熱水系統作為可供替代之選項，利用迴避成本(Avoided Cost)推估台灣各地區住宅部門改採熱泵熱水系統之成本效益。此外，參考歐美先進國家熱泵系統補助政策，以及台灣現有「太陽能熱水系統推廣獎勵措施」之政府政策補助方案，設定各相關參數，俾模擬政府補貼方案情境下之成本效益分析。 分析結果以淨現值(Net Present Value)、益本比(Benefit-Cost Ratio)及折現回收期(Discounted Payback Period )呈現，結論可從兩個觀點之檢定加以評估。其一、以「參與者檢定」評估是否有足夠的經濟誘因，促使住宅用戶裝設熱泵熱水系統。其二、以「總資源成本檢定」，評估推廣熱泵系統對於整體社會是否具有淨效益。 本研究中全台12個地區，若以熱泵系統取代電能熱水系統、LPG瓦斯熱水系統、NG瓦斯熱水系統三種既有設備，交叉比對之33個替代方案，由「參與者檢定」之結果顯示，所有替代方案之益本比均大於1.1；折現回收期最長達11.3年，最短僅3.2年。若模擬政府補助18,000名用戶採用熱泵系統，則「總資源成本檢定」之結果中，所有替代方案之益本比介乎1至1.73之間；折現回收期最長達14.9年，最短僅5.4年；住宅部門以熱泵替代現有電能、LPG瓦斯、NG瓦斯熱水系統至少可降低碳排放量每年2,707公噸。三種替代類別中以電能熱水系統替代方案益本比最高(介乎1.55至1.73)；LPG瓦斯替代方案之益本比居次(介乎1.19至1.28)；NG瓦斯替代方案益本比最低(介乎1.0至1.06)。全台12個地區考量環境溫度差異之影響以南投分區改採熱泵系統的益本比最高(電能替代1.73、LPG瓦斯替代1.28、NG瓦斯替代1.06)，屏東分區的益本比為最低(電能替代1.55、LPG瓦斯替代1.19、NG瓦斯替代1.0)。 若考量熱泵系統市場滲透率，以熱泵取代NG瓦斯熱水系統之市佔率達5%、20%、50%時，台灣整體社會的淨現值分別為251百萬元、1,006百萬元與2,514百萬元，且每年可減少碳排放量27,169公噸、108,675公噸以及271,687公噸。 / As an island country, 99% energy supply in Taiwan depends on importation due to the very limited endogenous energy. In order to maintain both energy security and stability, improving energy efficiency of consumer end-use is an important government policy. Heat pump systems have been widely applied and strongly promoted in Europe and United State for its uniquely energy saving and CO2 reducing capability. Therefore, the motivation of this study is to access the regional applicability of heat pump water heating system for Taiwan’s climate and residential building types by cost-benefit analysis method. To demonstrate the regional difference of climatic conditions and energy prices heat pump application, Taiwan is divided in twelve regions with three kinds of alternative residential water heating systems (i.e. electric heating, LPG tank heating, and NG pipe heating). Under these conditions, we utilize the avoided cost method to access itemized costs and benefits of heat pump water heating systems in various regional families in Taiwan. In addition, referring to heat pump incentive scheme in advanced European countries and North America while considering solar water heating systems incentive policy in Taiwan, we also simulate variation of parameters (such as cash rebate subside, total residential heat pump user numbers )of heat pump system subsidy program. The outcome of cost-benefit analysis is presented in a form as net present value (NPV), benefit-cost ratio (BCR), and discounted payback period (DP). The results could be analyzed by test from two different perspectives including Participant Test (PCT) from participant perspective and Total Resource Cost Test (TRC) from overall sociality perspective. All of the 33 alternative programs constituted by 12 regions with electric , LPG and NG systems, for PCT, BCR, all 33 alternative programs are greater than 1.1; DP are between 3.2 to 11.3 years. For TRC, BCR, all 33 alternative programs are greater than 1 but less than 1.73; DP are between 5.4 to 14.9 years. Residential building adopting heat pump could reduce 2,707 tons carbon emissions annually. For the three types of alternative system, BCR of electric heating alternative program is the largest and NG alternative program being the least. For all of the 12 regions, BCR of Nantou region is the largest for adopting heat pump while BCR of Pingtung region is the smallest. NPV of overall Taiwan with market penetration reaching 5%, 20% and 50% substitution rate from heat pump system to NG water heating system are 251 million NT$, 1,006 million NT$, and 2,514 million NT$ respectively. Carbon emissions reduce 27,169 tons, 108,675 tons and 271,687 tons annually.