Heat-pump water heater dimensions on the list

Of the 609 certified heat-pump model numbers, 603 list a tank height and diameter. A 240-volt integrated tank under 50 gallons of rated volume has a median listed height of 62.3 in; split-system tanks in the same volume range list a median of 46.6 in, and the shortest heat-pump tank on the list is a split system.

What the two fields are

Each ENERGY STAR listing has a tank height and a tank diameter in inches, entered by the partner that certified the model. They are not part of the DOE test, and the listing does not say whether the height includes fittings or the space a unit needs above or around it. Values of 0 or 1 in, which appear as placeholders in the source, were removed, which is why six heat-pump model numbers show no dimensions on this site.

Height and diameter by group

Listed tank height and diameter by subtype and rated volume (model numbers)
Group	Model numbers	Height, in	Median height	Diameter, in	Median diameter
240 V integrated, under 50 gal	180	37.6–66.4	62.3	15–28	20.3
240 V integrated, 50 to 69 gal	127	44.6–76.1	61	18.5–30	23
240 V integrated, 70 gal and up	134	41.7–86	69	19.7–30	24.3
120 V plug-in, under 50 gal	33	39.4–65	62.3	15–22.3	20.3
120 V plug-in, 50 to 69 gal	18	47.5–64.2	61	18.5–24.3	23
120 V plug-in, 70 gal and up	17	57.2–92	74.2	20–27	24.3
Split system, under 50 gal	50	33–72.7	46.6	16–22.5	18
Split system, 50 to 69 gal	19	59	59	18–22	18
Split system, 70 gal and up	25	53–73.4	58	18.5–30	20

Integrated tanks grow in both height and diameter. The 240-volt integrated group runs from a median of 62.3 in tall under 50 gallons to 69 in at 70 gallons and up, while the median diameter widens from 20.3 to 24.3 in.

The common sizes

Four rated volumes account for most 240-volt integrated listings. Their listed heights: at 36 gal, 52 model numbers from 62.3 to 66 in; at 45 gal, 49 model numbers from 45.3 to 61.8 in; at 46 gal, 44 model numbers from 46.6 to 66.4 in; at 72 gal, 47 model numbers from 62.7 to 74.2 in. The spread inside one rated volume comes from different designs, not from rounding: the same rated volume can sit in a squat, wide tank or a tall, slim one.

Plug-in 120-volt tanks under 50 gallons list the same median height and diameter as the 240-volt tanks of that size, 62.3 by 20.3 in, which fits the many plug-in models that share a tank family with a 240-volt version. Above 70 gallons the plug-in group is taller, with a median of 74.2 in against 69 in for 240-volt tanks.

Split systems are shorter

A split system keeps its compressor in a separate unit, and the listed tanks show it. Under 50 gallons of rated volume, split-system tanks list a median height 15.7 in below the 240-volt integrated tanks. The shortest heat-pump tank on the list is A. O. Smith HPACO-45 1+AXST-50LBTTP 1, at 33 in for 48 gal of rated volume.

The extremes

The tallest listed heat-pump tank is State HPVX-80-DHPT 2, 92 in for 82 gal rated (120 V plug-in). The widest is Vaughn Thermal MP80FHPT at 30 in, and the slimmest A. O. Smith CAHP-50 2 at 15 in. Among 240-volt integrated tanks of 70 gallons and up, the shortest is 1HVAC ACIQ-80G-HP-WH, listed at 41.7 in.

Same volume, different shapes

Rated volume says little about shape. Between 45 and 50 gallons of rated volume, 195 model numbers list dimensions, from A. O. Smith HPACO-45 1+AXST-50LBTTP 1 at 33 in tall to Eco-Logical OMNI-50HP2-1A at 72.7 in. For a tight space, the listed height and diameter are the figures to compare, and the Heater finder shows both for any set you tick.

When one rating set lists two sizes

A rating set groups model numbers with identical certified ratings, and almost always one listed size. In five heat-pump sets the model numbers report more than one height. In the Rheem PROPH40 T0 RH120-M set, for example, the Friedrich model numbers list 45.5 × 16 in while the Rheem ones list 62.3 × 20.3 in, with the same first-hour rating and UEF. This site shows each model number’s own figures and never averages them; when two listings of one design disagree, the manufacturer’s current specification sheet is the place to check.

Against gas storage tanks

The 134 gas storage model numbers on the list, residential-duty commercial tanks included, are shorter on the whole: listed heights run from 44.7 to 74 in with a median of 54.5 in, against 61.8 in for all heat-pump tanks with dimensions. Gas tank diameters run from 18 to 27 in. The two types are rated differently, so this compares shapes only, not output.

What the figures do not cover

Clearances, air volume and drainage requirements, which are set by each manufacturer’s installation instructions.
Weight, which the listing does not carry.
Any space the outdoor unit of a split system needs.

Each model-line page lists the height and diameter of every model number in that line.

Heat-pump water heater dimensions: listed height and diameter by size