Home / Model lines / Carnot Labs N51 Heat pump · 240 V integrated
Carnot Labs N51 Carnot Labs N51 is a 240 V integrated heat-pump water heater certified as a single rating set, a single model number sold as Carnot Labs, listed by Carnot Labs. Rated volume 47 gal, first-hour rating 75 gal, UEF 3.53 at the high draw pattern and 1,404 kWh/yr in the DOE test. That UEF is 0.35 below the median of the 58 high-draw heat-pump sets (3.88).
Certified as of October 27, 2026 · EPA ENERGY STAR data, public domain · Compare in the Heater finder
Certified values Certified values of Carnot Labs N51 Rating set Rated volume, gal First hour, gal Per rated gal UEF UEF rank kWh/yr Carnot Labs N51 1 model number 47 75 1.60 3.53 high 17th lowest of 58 1,404
Carnot Labs N51: first-hour rating against rated volume
First-hour rating, gal
Carnot Labs N51: 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 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 Giant GTHPCO-45 1+GTXST-50S 1 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 Carnot Labs N51
Carnot Labs N51: 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 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 Giant GTHPCO-45 1+GTXST-50S 1 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 Carnot Labs N51
Filled: the Carnot Labs N51; 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 1.60×, on Carnot Labs N51.
Where this set stands Measure Value Median of the group Placing Compared with UEF 3.53 3.88 17th lowest of 58 58 high-draw heat-pump sets First-hour rating 75 gal 77 gal 44th lowest of 101, four tied 101 heat-pump sets Rated electricity use 1,404 kWh/yr 1,268 kWh/yr ninth highest of 58 58 high-draw heat-pump sets Compressor cut-off 40 °F 36.3 °F tenth highest of 90 90 heat-pump sets that report one First-hour output per rated gallon 1.60 1.25 sixth highest of 101, two tied 101 heat-pump sets Rated volume 47 gal 61 gal 33rd lowest of 101, three tied 101 heat-pump sets
Model numbers The set covers a single model number, certified 2026-02-10.
Model number Brand Height × diameter Electrical Refrigerant Connected Certified N51 Carnot Labs 44.2 × 18.9 in 240 V / 21.6 A R-513A no 2026-02-10
Nearest certified alternatives