DoesTheMath

A. O. SMITH GPVT-40 2** vs RELIANCE WATER HEATERS GPCT-40L 1**: which uses less energy?

At the high draw pattern the RELIANCE WATER HEATERS GPCT-40L 1** uses 188 therms a year and the A. O. SMITH GPVT-40 2** 242 — 54 therms (22%) less, about 537 therms over ten years. Both are filed as a gas tank, so the comparison holds. Enter your ZIP below to price the difference.

Side by side

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

Filed and computed figures
A. O. SMITH GPVT-40 2** RELIANCE WATER HEATERS GPCT-40L 1**
UEF (Uniform Energy Factor) 0.7 0.9 (better)
Energy use per year (therms) 242 188 (better)
First hour rating (gal) 87 86
Rated storage volume (gal) 38 38
Installed cost range $1,993–$3,665 not published
ENERGY STAR certified not matched yes
On the market since not filed 2021-10-01
DOE CCD · 2026-09-19

What it costs to run

A. O. SMITH GPVT-40 2**: 242 therms a year RELIANCE WATER HEATERS GPCT-40L 1**: 188 therms a year

A. O. SMITH GPVT-40 2** — 242 therms a year RELIANCE WATER HEATERS GPCT-40L 1** — 188 therms a year

RELIANCE WATER HEATERS GPCT-40L 1** is 54 therms a year lower than A. O. SMITH GPVT-40 2**.

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.
  • The actual warranty term is printed in each model’s documentation, not in any registry.

Which should you pick?

  • Pick the RELIANCE WATER HEATERS GPCT-40L 1** if running cost matters most: it uses 54 therms less a year on the same test.
  • Pick the A. O. SMITH GPVT-40 2** if you need more hot water in your busiest hour: it lists a first hour rating of 87 gallons against 86.
  • Neither if your household's busiest hour needs more than 87 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

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