Home / Model lines / Giant GTHPCO-45 1+GTXST-50S 1 Heat pump · split system
Giant GTHPCO-45 1+GTXST-50S 1 Giant GTHPCO-45 1+GTXST-50S 1 is a split system heat-pump water heater certified as a single rating set, 25 model numbers sold under eight brand names, listed by A.O. Smith. Rated volume 46 gal, first-hour rating 70 gal, UEF 3.52 at the medium draw pattern and 923 kWh/yr in the DOE test. That UEF is 0.04 below the median of the 38 medium-draw heat-pump sets (3.56).
Certified as of October 27, 2026 · EPA ENERGY STAR data, public domain · Compare in the Heater finder
Certified values Certified values of Giant GTHPCO-45 1+GTXST-50S 1 Rating set Rated volume, gal First hour, gal Per rated gal UEF UEF rank kWh/yr Giant GTHPCO-45 1+GTXST-50S 1 25 model numbers 46 70 1.52 3.52 medium 15th lowest of 38, two tied 923
Giant GTHPCO-45 1+GTXST-50S 1: first-hour rating against rated volume
First-hour rating, gal
Giant GTHPCO-45 1+GTXST-50S 1: first-hour rating against rated volume 40 60 80 100 120 140 30 40 50 60 70 80 90 100 110 120 Rated volume, gal 1× 1.5× A. O. Smith CAHP-40 2 A. O. Smith CAHP-50 2 A. O. Smith CAHP-66 2 A. O. Smith CAHP-80 2 A. O. Smith FPTU-50 1 A. O. Smith FPTU-66 1 A. O. Smith FPTU-80 1 A. O. Smith HP1050H45DV 1 A. O. Smith HP1080H45DV 1 A. O. Smith HPACO-45 1+AXST-50LBTTP 1 A. O. Smith HPACO-45 1+AXST-50T 1 A. O. Smith HPACO-45 1+AXST-66 1 A. O. Smith HPACO-45 1+AXST-80 1 A. O. Smith HPS10-50H45DV 2 A. O. Smith HPS10-66H45DV 2 A. O. Smith HPS10-80H45DV 2 A. O. Smith HPTU-66CTA 1 A. O. Smith HPTV-50 2 A. O. Smith HPTV-66 2 A. O. Smith HPTV-80 2 American Standard ASHPWH-40 American Standard ASHPWH-50 American Standard ASHPWH-65 American Standard ASHPWH-80 Arctic Arctic-HP-Hot Water-KA06-50 Arctic Arctic-HP-Hot Water-KA06-80 Ariston ARIHPWH-40-T Ariston ARIHPWH-50-T Ariston ARIHPWH-65-T Ariston ARIHPWH-80-T Bradford White RE2H50S- Bradford White RE2H65T- Bradford White RE2H80T- Bradford White RE2HP50-1NCTT Bradford White RE2HP65-1NCTT Bradford White RE2HP80-1NCTT Carnot Labs N51 Eco-Logical OMNI-50HP1-1A Eco-Logical OMNI-50HP2-1A Eco-Logical OMNI-80HP2-1A Friedrich PROH40 T2 FD310BM Friedrich PROH50 T2 FD310BM Friedrich PROH65 T2 FD310BM Friedrich PROH80 T2 FD310BM GE Profile PF40S10FPY01 GE Profile PF50S10FPY01 GE Profile PF65S10FPY01 GE Profile PF80S10FPY01 GE Profile PH40S10BPY01 GE Profile PH50S10BNY01 GE Profile PH50S10BPY01 GE Profile PH65S10BNY01 GE Profile PH65S10BPY01 GE Profile PH80S10BNY01 GE Profile PH80S10BPY01 Gree GRS-3.0Pd/TD50GANhA-D Gree GRS-3.0Pd/TD70GANhA-D LG APHWC501D LG APHWC502D LG APHWC801D LG APHWC802D Midea CAN3-RSJ-15/190RDVN3-L3 Midea CAN3-RSJ-15/190RDVN3-L4 Midea CAN3-RSJ-15/250RDVN3-L3 Midea CAN3-RSJ-15/250RDVN3-L4 Midea CAN3-RSJ-15/300RDVN3-L3 Midea CAN3-RSJ-15/300RDVN3-L4 Navien NWP500S050AUMB Navien NWP500S065AUMB Navien NWP500S080AUMB Reclaim Energy MP120F-RC Reclaim Energy MP80F-RC Rheem PROPH40 T0 RH120-M Rheem PROPH40 T2 RH375-15 Rheem PROPH40 T2 RH375-30 Rheem PROPH50 T0 RH120 Rheem PROPH50 T0 RH120-M Rheem PROPH50 T2 RH375-15 Rheem PROPH50 T2 RH375-30 Rheem PROPH65 T0 RH120-M Rheem PROPH65 T2 RH375-15 Rheem PROPH65 T2 RH375-30 Rheem PROPH80 T0 RH120-M Rheem PROPH80 T2 RH375-15 Rheem PROPH80 T2 RH375-30 Rinnai REHP50 Rinnai REHP80 SanCO2 GS5-45HPC HP + ECO-119GLBK SanCO2 GS5-45HPC HP + ECO-43SSAQB SanCO2 GS5-45HPC HP + ECO-83SSAQB Smart Solar SSG2-ES 120 Smart Solar SSG2-ES 65 Smart Solar SSG2-ES 80 Vaughn Thermal ME120HPT Vaughn Thermal ME50HPT Vaughn Thermal ME65HPT Vaughn Thermal ME80HPT Vaughn Thermal MP120FHPT Vaughn Thermal MP55FHPT Vaughn Thermal MP80FHPT Giant GTHPCO-45 1+GTXST-50S 1
Giant GTHPCO-45 1+GTXST-50S 1: first-hour rating against rated volume 40 60 80 100 120 140 30 60 90 120 Rated volume, gal A. O. Smith CAHP-40 2 A. O. Smith CAHP-50 2 A. O. Smith CAHP-66 2 A. O. Smith CAHP-80 2 A. O. Smith FPTU-50 1 A. O. Smith FPTU-66 1 A. O. Smith FPTU-80 1 A. O. Smith HP1050H45DV 1 A. O. Smith HP1080H45DV 1 A. O. Smith HPACO-45 1+AXST-50LBTTP 1 A. O. Smith HPACO-45 1+AXST-50T 1 A. O. Smith HPACO-45 1+AXST-66 1 A. O. Smith HPACO-45 1+AXST-80 1 A. O. Smith HPS10-50H45DV 2 A. O. Smith HPS10-66H45DV 2 A. O. Smith HPS10-80H45DV 2 A. O. Smith HPTU-66CTA 1 A. O. Smith HPTV-50 2 A. O. Smith HPTV-66 2 A. O. Smith HPTV-80 2 American Standard ASHPWH-40 American Standard ASHPWH-50 American Standard ASHPWH-65 American Standard ASHPWH-80 Arctic Arctic-HP-Hot Water-KA06-50 Arctic Arctic-HP-Hot Water-KA06-80 Ariston ARIHPWH-40-T Ariston ARIHPWH-50-T Ariston ARIHPWH-65-T Ariston ARIHPWH-80-T Bradford White RE2H50S- Bradford White RE2H65T- Bradford White RE2H80T- Bradford White RE2HP50-1NCTT Bradford White RE2HP65-1NCTT Bradford White RE2HP80-1NCTT Carnot Labs N51 Eco-Logical OMNI-50HP1-1A Eco-Logical OMNI-50HP2-1A Eco-Logical OMNI-80HP2-1A Friedrich PROH40 T2 FD310BM Friedrich PROH50 T2 FD310BM Friedrich PROH65 T2 FD310BM Friedrich PROH80 T2 FD310BM GE Profile PF40S10FPY01 GE Profile PF50S10FPY01 GE Profile PF65S10FPY01 GE Profile PF80S10FPY01 GE Profile PH40S10BPY01 GE Profile PH50S10BNY01 GE Profile PH50S10BPY01 GE Profile PH65S10BNY01 GE Profile PH65S10BPY01 GE Profile PH80S10BNY01 GE Profile PH80S10BPY01 Gree GRS-3.0Pd/TD50GANhA-D Gree GRS-3.0Pd/TD70GANhA-D LG APHWC501D LG APHWC502D LG APHWC801D LG APHWC802D Midea CAN3-RSJ-15/190RDVN3-L3 Midea CAN3-RSJ-15/190RDVN3-L4 Midea CAN3-RSJ-15/250RDVN3-L3 Midea CAN3-RSJ-15/250RDVN3-L4 Midea CAN3-RSJ-15/300RDVN3-L3 Midea CAN3-RSJ-15/300RDVN3-L4 Navien NWP500S050AUMB Navien NWP500S065AUMB Navien NWP500S080AUMB Reclaim Energy MP120F-RC Reclaim Energy MP80F-RC Rheem PROPH40 T0 RH120-M Rheem PROPH40 T2 RH375-15 Rheem PROPH40 T2 RH375-30 Rheem PROPH50 T0 RH120 Rheem PROPH50 T0 RH120-M Rheem PROPH50 T2 RH375-15 Rheem PROPH50 T2 RH375-30 Rheem PROPH65 T0 RH120-M Rheem PROPH65 T2 RH375-15 Rheem PROPH65 T2 RH375-30 Rheem PROPH80 T0 RH120-M Rheem PROPH80 T2 RH375-15 Rheem PROPH80 T2 RH375-30 Rinnai REHP50 Rinnai REHP80 SanCO2 GS5-45HPC HP + ECO-119GLBK SanCO2 GS5-45HPC HP + ECO-43SSAQB SanCO2 GS5-45HPC HP + ECO-83SSAQB Smart Solar SSG2-ES 120 Smart Solar SSG2-ES 65 Smart Solar SSG2-ES 80 Vaughn Thermal ME120HPT Vaughn Thermal ME50HPT Vaughn Thermal ME65HPT Vaughn Thermal ME80HPT Vaughn Thermal MP120FHPT Vaughn Thermal MP55FHPT Vaughn Thermal MP80FHPT Giant GTHPCO-45 1+GTXST-50S 1
Filled: the Giant GTHPCO-45 1+GTXST-50S 1; open circles: the other 100 heat-pump sets. Dashed lines mark 1× and 1.5× the rated volume; the highest ratio in the line is 1.52×, on Giant GTHPCO-45 1+GTXST-50S 1.
Where this set stands Measure Value Median of the group Placing Compared with UEF 3.52 3.56 15th lowest of 38, two tied 38 medium-draw heat-pump sets First-hour rating 70 gal 77 gal 38th lowest of 101, two tied 101 heat-pump sets Rated electricity use 923 kWh/yr 894 kWh/yr 12th highest of 38, two tied 38 medium-draw heat-pump sets First-hour output per rated gallon 1.52 1.25 14th highest of 101 101 heat-pump sets Rated volume 46 gal 61 gal 21st lowest of 101, 12 tied 101 heat-pump sets
Model numbers The set covers 25 model numbers under eight brand names, first certified 2026-02-25 and most recently 2026-03-19. An asterisk stands for a variant character in the model number.
Model number Brand Height × diameter Electrical Refrigerant Connected Certified HPACO-45 1**+AXST-50S 1** A. O. Smith 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 HPACO-45 1**+AXST-50STTP 1** A. O. Smith 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 HPACO-45C 1**+AXST-50SC 1** A. O. Smith 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 HPACO-45C 1**+AXST-50SCTTP 1** A. O. Smith 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 MHPCO-45 1**+MXST-50S 1** American 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 MHPCO-45 1**+MXST-50STTP 1** American 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 GHPCO-45 1**+GXST-50S 1* GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-04 GHPCO-45 1**+GXST-50S 1** GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GHPCO-45 1**+GXST-50STTP 1* GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-04 GHPCO-45 1**+GXST-50STTP 1** GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GHPCO-45 1**+GXST-50T 1** GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GHPCO-45 1**+GXST-50TTTP 1** GSW 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GTHPCO-45 1**+GTXST-50S 1* Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-04 GTHPCO-45 1**+GTXST-50S 1** Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GTHPCO-45 1**+GTXST-50STTP 1* Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-04 GTHPCO-45 1**+GTXST-50STTP 1** Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GTHPCO-45 1**+GTXST-50T 1** Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 GTHPCO-45 1**+GTXST-50TTTP 1** Giant 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 JWHPCO-45 1**+JWXST-50STTP 1** John Wood 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-03-19 LHPCO-45 1**+LXST-50S 1** Lochinvar 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 LHPCO-45 1**+LXST-50STTP 1** Lochinvar 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 RHPCO-45 1**+RXST-50S 1** Reliance 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 RHPCO-45 1**+RXST-50SG 1** Reliance 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 SHPCO-45 1**+SXST-50S 1** State 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25 SHPCO-45 1**+SXST-50SG 1** State 46.6 × 18 in 240 V / 20.2 A R-744 yes 2026-02-25
Nearest certified alternatives