A. O. SMITH HPTV-66 2 vs RELIANCE WATER HEATERS FPTU-66 1: which uses less energy?

At the high draw pattern the RELIANCE WATER HEATERS FPTU-66 1** uses 1,451 kWh a year and the A. O. SMITH HPTV-66 2** 1,550 — 100 kWh (6%) less, about 997 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
Figure	A. O. SMITH HPTV-66 2**	RELIANCE WATER HEATERS FPTU-66 1**
UEF (Uniform Energy Factor)	3.2	3.42 (better)
Energy use per year (kWh)	1,550	1,451 (better)
First hour rating (gal)	76	79
Rated storage volume (gal)	68	67
Installed cost range	$3,707–$4,067	$3,699–$4,278
ENERGY STAR certified	yes	yes
Sound level (dB)	45	not filed
Refrigerant	R-513A, GWP 630	R-134a, GWP 1430
On the market since	2023-07-10	2019-04-05

DOE CCD · 2026-09-19

What it costs to run

A. O. SMITH HPTV-66 2** — 1,550 kWh a year RELIANCE WATER HEATERS FPTU-66 1** — 1,451 kWh a year

RELIANCE WATER HEATERS FPTU-66 1** is 99 kWh a year lower than A. O. SMITH HPTV-66 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.
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 A. O. SMITH HPTV-66 2** since 2023-07-10, the RELIANCE WATER HEATERS FPTU-66 1** since 2019-04-05. A sale date, not a lifespan.

Which should you pick?

Pick the RELIANCE WATER HEATERS FPTU-66 1** if running cost matters most: it uses 100 kWh less a year on the same test.
Pick the A. O. SMITH HPTV-66 2** if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the RELIANCE WATER HEATERS FPTU-66 1**.
Neither if your household's busiest hour needs more than 79 gallons of hot water — neither lists more. Check whether a 65-gallon heater is enough.

Each model on its own

A. O. SMITH HPTV-66 2**

Its filed figures, class position and running cost on your ZIP.
RELIANCE WATER HEATERS FPTU-66 1**

Its filed figures, class position and running cost on your ZIP.