DoesTheMath

GIANT HPACO-45 1**+AXST-80 1** vs GREE GRS-3.0Pd/TD70GANhA-D: which uses less energy?

At the high draw pattern the GREE GRS-3.0Pd/TD70GANhA-D uses 1,231 kWh a year and the GIANT HPACO-45 1**+AXST-80 1** 1,306 — 75 kWh (6%) less, about 745 kWh over ten years. Both are filed as an electric tank, so the comparison holds. Enter your ZIP below to price the difference.

Side by side

Compared within one class only: models filed as an electric tank at the high draw pattern.

Filed and computed figures
GIANT HPACO-45 1**+AXST-80 1** GREE GRS-3.0Pd/TD70GANhA-D
UEF (Uniform Energy Factor) 3.8 4.03 (better)
Energy use per year (kWh) 1,306 1,231 (better)
First hour rating (gal) 95 100
Rated storage volume (gal) 73 68
Installed cost range $3,938–$4,714 $3,802–$4,897
ENERGY STAR certified yes yes
Refrigerant R-744 (CO2), GWP 1 R-32
On the market since 2026-02-13 2025-11-17
DOE CCD · 2026-09-19

What it costs to run

GIANT HPACO-45 1**+AXST-80 1**: 1,306 kWh a year GREE GRS-3.0Pd/TD70GANhA-D: 1,231 kWh a year

GIANT HPACO-45 1**+AXST-80 1** — 1,306 kWh a year GREE GRS-3.0Pd/TD70GANhA-D — 1,231 kWh a year

GREE GRS-3.0Pd/TD70GANhA-D is 75 kWh a year lower than GIANT HPACO-45 1**+AXST-80 1**.

DOE CCD · 2026-09-19

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Reliability

Not published: Reliability, failure rates and each model’s actual warranty term.

The registries these figures come from certify energy performance under a federal test; none of them records how long a unit lasts or how often it fails, so this page does not rank the two on reliability.

What is here instead:

  • The filed efficiency, capacity and tank size of both models, side by side below.
  • Both are ENERGY STAR certified, which requires a manufacturer warranty of at least six years; the actual term for each model is not published.
  • Time on the market, as filed with ENERGY STAR: the GIANT HPACO-45 1**+AXST-80 1** since 2026-02-13, the GREE GRS-3.0Pd/TD70GANhA-D since 2025-11-17. A sale date, not a lifespan.

Which should you pick?

  • Pick the GREE GRS-3.0Pd/TD70GANhA-D if running cost matters most: it uses 75 kWh less a year on the same test.
  • Pick the GIANT HPACO-45 1**+AXST-80 1** if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the GREE GRS-3.0Pd/TD70GANhA-D.
  • Neither if your household's busiest hour needs more than 100 gallons of hot water — neither lists more. Check whether a 65-gallon heater is enough.

Each model on its own

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