FRIEDRICH RTGH-S11I vs VESTA VRS PLUS-199: which uses less energy?

At the high draw pattern the FRIEDRICH RTGH-S11I and the VESTA VRS PLUS-199 use the same energy, 176 therms a year each, on the same federal test. Both are filed as a gas tankless unit, so the comparison holds; what separates them is below. Enter your ZIP to price either one on your own rate.

Side by side

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

Filed and computed figures
Figure	FRIEDRICH RTGH-S11I	VESTA VRS PLUS-199
UEF (Uniform Energy Factor)	0.96	0.96
Energy use per year (therms)	176	176
Max flow (GPM)	5.8	5.9
Installed cost range	$2,405–$3,460	$2,405–$3,460
ENERGY STAR certified	yes	yes
On the market since	2022-08-01	2023-10-16

DOE CCD · 2026-09-19

What it costs to run

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 FRIEDRICH RTGH-S11I since 2022-08-01, the VESTA VRS PLUS-199 since 2023-10-16. A sale date, not a lifespan.

Which should you pick?

Pick the FRIEDRICH RTGH-S11I if its price or availability suits you — on energy the two are level.
Pick the VESTA VRS PLUS-199 if you run more fixtures at once: it lists 5.9 GPM against 5.8.
Neither if you need more than 5.9 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own

FRIEDRICH RTGH-S11I

Its filed figures, class position and running cost on your ZIP.
VESTA VRS PLUS-199

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