waterheaterspecs

Ariston USA LLC

Ariston USA LLC is the ENERGY STAR partner of record for 22 certified model numbers in 14 rating sets (16 heat-pump, 6 residential-duty commercial gas storage), under 4 brand names. HTP PH100-80 has the highest UEF of all 15 high-draw residential-duty commercial gas storage sets on the list, 0.93. The median UEF of this partner’s high-draw sets, 4.03, is the highest of the six maker pages with enough high-draw sets. Of this partner’s model numbers, 73% are listed as connected-capable, the highest share of the seven maker pages on this site.

Certified models as of October 27, 2026 · Open these sets in the Heater finder

First-hour rating against rated volume, this partner against the rest of the heat-pump list

Listed hereOther heat-pump sets

First-hour rating, gal

First-hour rating against rated volume, this partner against the rest of the heat-pump list40608010012014030405060708090100110120Rated volume, gal1×1.5×A. O. Smith CAHP-40 2A. O. Smith CAHP-50 2A. O. Smith CAHP-66 2A. O. Smith CAHP-80 2A. O. Smith FPTU-50 1A. O. Smith FPTU-66 1A. O. Smith FPTU-80 1A. O. Smith HP1050H45DV 1A. O. Smith HP1080H45DV 1A. O. Smith HPACO-45 1+AXST-50LBTTP 1A. O. Smith HPACO-45 1+AXST-50T 1A. O. Smith HPACO-45 1+AXST-66 1A. O. Smith HPACO-45 1+AXST-80 1A. O. Smith HPS10-50H45DV 2A. O. Smith HPS10-66H45DV 2A. O. Smith HPS10-80H45DV 2A. O. Smith HPTU-66CTA 1A. O. Smith HPTV-50 2A. O. Smith HPTV-66 2A. O. Smith HPTV-80 2Arctic Arctic-HP-Hot Water-KA06-50Arctic Arctic-HP-Hot Water-KA06-80Bradford White RE2H50S-Bradford White RE2H65T-Bradford White RE2H80T-Bradford White RE2HP50-1NCTTBradford White RE2HP65-1NCTTBradford White RE2HP80-1NCTTCarnot Labs N51Eco-Logical OMNI-50HP1-1AEco-Logical OMNI-50HP2-1AEco-Logical OMNI-80HP2-1AFriedrich PROH40 T2 FD310BMFriedrich PROH50 T2 FD310BMFriedrich PROH65 T2 FD310BMFriedrich PROH80 T2 FD310BMGE Profile PF40S10FPY01GE Profile PF50S10FPY01GE Profile PF65S10FPY01GE Profile PF80S10FPY01GE Profile PH40S10BPY01GE Profile PH50S10BNY01GE Profile PH50S10BPY01GE Profile PH65S10BNY01GE Profile PH65S10BPY01GE Profile PH80S10BNY01GE Profile PH80S10BPY01Giant GTHPCO-45 1+GTXST-50S 1Gree GRS-3.0Pd/TD50GANhA-DGree GRS-3.0Pd/TD70GANhA-DLG APHWC501DLG APHWC502DLG APHWC801DLG APHWC802DMidea CAN3-RSJ-15/190RDVN3-L3Midea CAN3-RSJ-15/190RDVN3-L4Midea CAN3-RSJ-15/250RDVN3-L3Midea CAN3-RSJ-15/250RDVN3-L4Midea CAN3-RSJ-15/300RDVN3-L3Midea CAN3-RSJ-15/300RDVN3-L4Navien NWP500S050AUMBNavien NWP500S065AUMBNavien NWP500S080AUMBReclaim Energy MP120F-RCReclaim Energy MP80F-RCRheem PROPH40 T0 RH120-MRheem PROPH40 T2 RH375-15Rheem PROPH40 T2 RH375-30Rheem PROPH50 T0 RH120Rheem PROPH50 T0 RH120-MRheem PROPH50 T2 RH375-15Rheem PROPH50 T2 RH375-30Rheem PROPH65 T0 RH120-MRheem PROPH65 T2 RH375-15Rheem PROPH65 T2 RH375-30Rheem PROPH80 T0 RH120-MRheem PROPH80 T2 RH375-15Rheem PROPH80 T2 RH375-30Rinnai REHP50Rinnai REHP80SanCO2 GS5-45HPC HP + ECO-119GLBKSanCO2 GS5-45HPC HP + ECO-43SSAQBSanCO2 GS5-45HPC HP + ECO-83SSAQBSmart Solar SSG2-ES 120Smart Solar SSG2-ES 65Smart Solar SSG2-ES 80Vaughn Thermal ME120HPTVaughn Thermal ME50HPTVaughn Thermal ME65HPTVaughn Thermal ME80HPTVaughn Thermal MP120FHPTVaughn Thermal MP55FHPTVaughn Thermal MP80FHPTAmerican Standard ASHPWH-40American Standard ASHPWH-50American Standard ASHPWH-65American Standard ASHPWH-80Ariston ARIHPWH-40-TAriston ARIHPWH-50-TAriston ARIHPWH-65-TAriston ARIHPWH-80-THTP PH100-119HTP PH100-55HTP PH100-80HTP PH76-50HTP PH76-60HTP PH76-80Ariston ARIHPWH-80-T
First-hour rating against rated volume, this partner against the rest of the heat-pump list406080100120140306090120Rated volume, galA. O. Smith CAHP-40 2A. O. Smith CAHP-50 2A. O. Smith CAHP-66 2A. O. Smith CAHP-80 2A. O. Smith FPTU-50 1A. O. Smith FPTU-66 1A. O. Smith FPTU-80 1A. O. Smith HP1050H45DV 1A. O. Smith HP1080H45DV 1A. O. Smith HPACO-45 1+AXST-50LBTTP 1A. O. Smith HPACO-45 1+AXST-50T 1A. O. Smith HPACO-45 1+AXST-66 1A. O. Smith HPACO-45 1+AXST-80 1A. O. Smith HPS10-50H45DV 2A. O. Smith HPS10-66H45DV 2A. O. Smith HPS10-80H45DV 2A. O. Smith HPTU-66CTA 1A. O. Smith HPTV-50 2A. O. Smith HPTV-66 2A. O. Smith HPTV-80 2Arctic Arctic-HP-Hot Water-KA06-50Arctic Arctic-HP-Hot Water-KA06-80Bradford White RE2H50S-Bradford White RE2H65T-Bradford White RE2H80T-Bradford White RE2HP50-1NCTTBradford White RE2HP65-1NCTTBradford White RE2HP80-1NCTTCarnot Labs N51Eco-Logical OMNI-50HP1-1AEco-Logical OMNI-50HP2-1AEco-Logical OMNI-80HP2-1AFriedrich PROH40 T2 FD310BMFriedrich PROH50 T2 FD310BMFriedrich PROH65 T2 FD310BMFriedrich PROH80 T2 FD310BMGE Profile PF40S10FPY01GE Profile PF50S10FPY01GE Profile PF65S10FPY01GE Profile PF80S10FPY01GE Profile PH40S10BPY01GE Profile PH50S10BNY01GE Profile PH50S10BPY01GE Profile PH65S10BNY01GE Profile PH65S10BPY01GE Profile PH80S10BNY01GE Profile PH80S10BPY01Giant GTHPCO-45 1+GTXST-50S 1Gree GRS-3.0Pd/TD50GANhA-DGree GRS-3.0Pd/TD70GANhA-DLG APHWC501DLG APHWC502DLG APHWC801DLG APHWC802DMidea CAN3-RSJ-15/190RDVN3-L3Midea CAN3-RSJ-15/190RDVN3-L4Midea CAN3-RSJ-15/250RDVN3-L3Midea CAN3-RSJ-15/250RDVN3-L4Midea CAN3-RSJ-15/300RDVN3-L3Midea CAN3-RSJ-15/300RDVN3-L4Navien NWP500S050AUMBNavien NWP500S065AUMBNavien NWP500S080AUMBReclaim Energy MP120F-RCReclaim Energy MP80F-RCRheem PROPH40 T0 RH120-MRheem PROPH40 T2 RH375-15Rheem PROPH40 T2 RH375-30Rheem PROPH50 T0 RH120Rheem PROPH50 T0 RH120-MRheem PROPH50 T2 RH375-15Rheem PROPH50 T2 RH375-30Rheem PROPH65 T0 RH120-MRheem PROPH65 T2 RH375-15Rheem PROPH65 T2 RH375-30Rheem PROPH80 T0 RH120-MRheem PROPH80 T2 RH375-15Rheem PROPH80 T2 RH375-30Rinnai REHP50Rinnai REHP80SanCO2 GS5-45HPC HP + ECO-119GLBKSanCO2 GS5-45HPC HP + ECO-43SSAQBSanCO2 GS5-45HPC HP + ECO-83SSAQBSmart Solar SSG2-ES 120Smart Solar SSG2-ES 65Smart Solar SSG2-ES 80Vaughn Thermal ME120HPTVaughn Thermal ME50HPTVaughn Thermal ME65HPTVaughn Thermal ME80HPTVaughn Thermal MP120FHPTVaughn Thermal MP55FHPTVaughn Thermal MP80FHPTAmerican Standard ASHPWH-40American Standard ASHPWH-50American Standard ASHPWH-65American Standard ASHPWH-80Ariston ARIHPWH-40-TAriston ARIHPWH-50-TAriston ARIHPWH-65-TAriston ARIHPWH-80-THTP PH100-119HTP PH100-55HTP PH100-80HTP PH76-50HTP PH76-60HTP PH76-80Ariston
Each circle is one rating set; filled circles grow with the number of model numbers. Dashed lines mark first-hour output of 1× and 1.5× the rated volume.

Rating sets by type

Heat pump, 8 rating sets

Heat-pump rating sets by draw pattern
Rating setRated volumeFirst-hour ratingUEFEnergyRefrigerantLow cut-off
High draw pattern4 of the 58 high-draw heat-pump sets
Ariston ARIHPWH-80-TAlso listed as Lennox
Show 2 model numbers
  • Ariston ARIHPWH-80-T
  • Lennox WHHP080T45MD240S****
74 gal88 gal4.101,210 kWh/yrR-513A35 °F
Ariston ARIHPWH-65-TAlso listed as Lennox
Show 2 model numbers
  • Ariston ARIHPWH-65-T
  • Lennox WHHP065T45MD240S****
61 gal77 gal4.051,225 kWh/yrR-513A35 °F
American Standard ASHPWH-80Also listed as Ariston
Show 2 model numbers
  • American Standard ASHPWH-80*****
  • Ariston ARIHPWH-80
73 gal87 gal4.011,238 kWh/yrR-134a35 °F
American Standard ASHPWH-65Also listed as Ariston
Show 2 model numbers
  • American Standard ASHPWH-65*****
  • Ariston ARIHPWH-65
62 gal78 gal3.851,289 kWh/yrR-134a35 °F
Medium draw pattern4 of the 38 medium-draw heat-pump sets
Ariston ARIHPWH-50-TAlso listed as Lennox
Show 2 model numbers
  • Ariston ARIHPWH-50-T
  • Lennox WHHP050T45MD240S****
45 gal69 gal3.83848 kWh/yrR-513A35 °F
American Standard ASHPWH-50Also listed as Ariston
Show 2 model numbers
  • American Standard ASHPWH-50*****
  • Ariston ARIHPWH-50
45 gal68 gal3.75867 kWh/yrR-134a35 °F
American Standard ASHPWH-40Also listed as Ariston
Show 2 model numbers
  • American Standard ASHPWH-40*****
  • Ariston ARIHPWH-40
37 gal66 gal3.58907 kWh/yrR-134a35 °F
Ariston ARIHPWH-40-TAlso listed as Lennox
Show 2 model numbers
  • Ariston ARIHPWH-40-T
  • Lennox WHHP040T45MD240S****
37 gal65 gal3.55915 kWh/yrR-513A35 °F

Gas storage, 6 rating sets

Gas storage rating sets
Rating setRated volumeFirst-hour ratingUEFGas useGas inputFuel
Gas storage, residential-duty commercial6 of 15 sets, all high draw
HTP PH76-80Highest first-hour rating of the 15 residential-duty commercial gas storage sets
Show 1 model number
  • HTP PH76-80****
77 gal206 gal0.87195 therms/yr76,000 Btu/hnatural gas or propane
HTP PH100-55
Show 1 model number
  • HTP PH100-55****
53 gal187 gal0.89190 therms/yr100,000 Btu/hnatural gas or propane
HTP PH100-119
Show 1 model number
  • HTP PH100-119****
112 gal178 gal0.90188 therms/yr100,000 Btu/hnatural gas or propane
HTP PH76-60
Show 1 model number
  • HTP PH76-60****
58 gal157 gal0.88192 therms/yr76,000 Btu/hnatural gas or propane
HTP PH76-50
Show 1 model number
  • HTP PH76-50****
48 gal154 gal0.90188 therms/yr76,000 Btu/hnatural gas or propane
HTP PH100-80
Show 1 model number
  • HTP PH100-80****
75 gal132 gal0.93182 therms/yr100,000 Btu/hnatural gas or propane

Compressor cut-off

The listed lower cut-off is the air temperature below which the compressor stops and backup heat takes over. Of the 8 sets here, 8 report a single value, from 35 °F up to 35 °F.

Lowest compressor operating temperature by rating setListed here8 setsAmerican Standard ASHPWH-40American Standard ASHPWH-50American Standard ASHPWH-65American Standard ASHPWH-80Ariston ARIHPWH-40-TAriston ARIHPWH-50-TAriston ARIHPWH-65-TAriston ARIHPWH-80-TOther heat pumps82 setsSanCO2 GS5-45HPC HP + ECO-119GLBKSanCO2 GS5-45HPC HP + ECO-83SSAQBSmart Solar SSG2-ES 120Smart Solar SSG2-ES 65Smart Solar SSG2-ES 80Reclaim Energy MP120F-RCReclaim Energy MP80F-RCEco-Logical OMNI-50HP1-1AEco-Logical OMNI-50HP2-1AEco-Logical OMNI-80HP2-1ALG APHWC501DLG APHWC502DLG APHWC801DLG APHWC802D23 sets2335 sets35Carnot Labs N51Navien NWP500S050AUMBNavien NWP500S065AUMBNavien NWP500S080AUMBA. O. Smith FPTU-50 1A. O. Smith FPTU-66 1A. O. Smith FPTU-80 1A. O. Smith HP1050H45DV 1A. O. Smith HP1080H45DV 1A. O. Smith HPTU-66CTA 1−30 °F−20 °F−10 °F0 °F10 °F20 °F30 °F40 °F50 °F
Lowest compressor operating temperatureListed here8 setsAmerican Standard ASHPWH-40American Standard ASHPWH-50American Standard ASHPWH-65American Standard ASHPWH-80Ariston ARIHPWH-40-TAriston ARIHPWH-50-TAriston ARIHPWH-65-TAriston ARIHPWH-80-TOther heat pumps82 setsSanCO2 GS5-45HPC HP + ECO-119GLBKSanCO2 GS5-45HPC HP + ECO-83SSAQBSmart Solar SSG2-ES 120Smart Solar SSG2-ES 65Smart Solar SSG2-ES 80Reclaim Energy MP120F-RCReclaim Energy MP80F-RCEco-Logical OMNI-50HP1-1AEco-Logical OMNI-50HP2-1AEco-Logical OMNI-80HP2-1ALG APHWC501DLG APHWC502DLG APHWC801DLG APHWC802D23 sets2335 sets35Carnot Labs N51Navien NWP500S050AUMBNavien NWP500S065AUMBNavien NWP500S080AUMBA. O. Smith FPTU-50 1A. O. Smith FPTU-66 1A. O. Smith FPTU-80 1A. O. Smith HP1050H45DV 1A. O. Smith HP1080H45DV 1A. O. Smith HPTU-66CTA 1−20 °F0 °F20 °F40 °F
One dot per rating set; stacks taller than eight are drawn as a bar with the count.

Refrigerants

Counted by model number, 16 with a listed refrigerant.

Fuel listing

Counted by model number. Separate natural-gas and propane versions of one heater usually carry their own model numbers.

Brand names under this partner

Model numbers per brand and type, counted only where Ariston USA LLC is the partner of record.

BrandHeat pumpGas storage, residential-duty commercialAll
Ariston8–8
HTP–66
American Standard4–4
Lennox4–4

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