The American Standard ASHPWH-xx line holds four certified rating sets of 240 V integrated heat-pump water heaters, 8 model numbers sold under two brand names, listed by Ariston USA. Rated volume runs from 37 to 73 gal, and the first-hour rating runs from 66 to 87 gal. UEFs compare only within a draw pattern; the two high-draw sets rate UEF from 3.85 to 4.01. American Standard ASHPWH-40 lists 1.78 gal of first-hour output per rated gallon, the highest of the 101 heat-pump sets. American Standard ASHPWH-80, the set with the most model numbers, rates 0.13 above the median UEF of the 58 high-draw heat-pump sets (3.88).
UEF ranks compare sets of the same draw pattern only.
American Standard ASHPWH-xx: first-hour rating against rated volume
American Standard ASHPWH-xxOther heat-pump sets
First-hour rating, gal
Filled: the four sets of American Standard ASHPWH-xx; open circles: the other 97 heat-pump sets. Dashed lines mark 1× and 1.5× the rated volume; the highest ratio in the line is 1.78×, on American Standard ASHPWH-40.
Across the sizes
From American Standard ASHPWH-40 to American Standard ASHPWH-80, rated volume grows by 36 gal and the first-hour rating by 21 gal: 0.58 gal of first-hour output for each added rated gallon.
The sizes test at different draw patterns (two high and two medium), so UEF and annual energy compare only between sizes that share a pattern (why).
Strongest placings, size by size
Measure
Value
Median of the group
Placing
Compared with
First-hour output per rated gallonAmerican Standard ASHPWH-40
1.78
1.25
highest of 101
101 heat-pump sets
Rated volumeAmerican Standard ASHPWH-40
37 gal
61 gal
sixth lowest of 101, two tied
101 heat-pump sets
UEFAmerican Standard ASHPWH-50
3.75
3.56
tenth highest of 38, five tied
38 medium-draw heat-pump sets
Rated volumeAmerican Standard ASHPWH-50
45 gal
61 gal
13th lowest of 101, eight tied
101 heat-pump sets
Compressor cut-offAmerican Standard ASHPWH-65
35 °F
36.3 °F
15th lowest of 90, 29 tied
90 heat-pump sets that report one
Rated electricity useAmerican Standard ASHPWH-65
1,289 kWh/yr
1,268 kWh/yr
25th highest of 58
58 high-draw heat-pump sets
Compressor cut-offAmerican Standard ASHPWH-80
35 °F
36.3 °F
15th lowest of 90, 29 tied
90 heat-pump sets that report one
UEFAmerican Standard ASHPWH-80
4.01
3.88
20th highest of 58
58 high-draw heat-pump sets
Model numbers
The line covers 8 model numbers under two brand names, first certified 2026-02-04 and most recently 2026-02-10. An asterisk stands for a variant character in the model number.