During　the　actual　operation　of　an　ASHP　unit　installed　in　different　climate　regions,　ambient　operating　conditions　can　vary　constantly　over　an　entire　heating　season,　thus　the　actual　output　heating　capacity　of　ASHP　units　may　vary　significantly　from　region　to　region.　To　enable　a　convenient　evaluation　of　output　heating　capacity　of　a　space　heating　ASHP　unit　installed　in　different　climate　regions,　regional　performance　evaluation　indexes　including　T-a＇,　HERR(Ta＇),　beta(Ta)　and　beta(RH)　based　on　ETD　method　have　been　developed.　These　evaluation　indexes　are　generalized　and　can　be　used　to　evaluate　the　regional　performance　of　ASHP　units　operated　in　any　regions.　It　can　also　be　used　to　specify　the　key　factors　affecting　the　operating　performances　of　ASHP　units　in　different　regions.　With　the　developed　evaluation　indexes,　the　regional　operating　performances　of　ASHP　units　installed　in　278　Chinese　cities　were　evaluated.　The　results　demonstrated　that　the　total　output　heating　energy　for　ASHP　units　operated　in　Southern　Chinese　provinces　may　be　lower　than　those　in　Northern　China.　In　Shanghai,　T-a＇　at　-6.0　degrees　C　is　lower　than　that　at　-3.0　degrees　C　in　Beijing,　suggesting　the　total　output　heating　energy　from　an　ASHP　units　operated　in　Shanghai　over　an　entire　heating　season　would　be　lower　than　that　in　Beijing.　Furthermore,　in　southern　Xinjiang　and　northern　Fujian　Provinces,　the　total　output　heating　energy　from　ASHP　units　may　be　higher　than　those　operated　at　the　nominal　condition.　In　addition,　in　Tibet,　Beijing,　Liaoning,　etc.,　the　total　output　heating　energy　from　the　ASHP　units　would　be　affected　more　by　T-a,　thus　ASHPs＇　manufacturers　are　recommended　to　develop　ASHP　units　suitable　for　operation　in　low　temperature　ambient.　In　most　regions　in　southern　China,　RH　would　affect　more　on　the　total　output　heating　energy　from　the　ASHP　units,　thus　ASHPs＇　manufacturers　are　recommended　to　develop　ASHP　units　having　frosting　suppression　provisions　and　accurate　defrosting　measures.　(C)　2021　Elsevier　B.V.　All　rights　reserved.