DoesTheMath

Mits Air US3-RSJ-15/300RDVN3-L3 vs RINNAI REHP80W: which uses less energy?

At the high draw pattern the Mits Air US3-RSJ-15/300RDVN3-L3 and the RINNAI REHP80W use the same energy, 1,240 kWh a year each, on the same federal test. Both are filed as an electric tank, 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 an electric tank at the high draw pattern.

Filed and computed figures
Mits Air US3-RSJ-15/300RDVN3-L3 RINNAI REHP80W
UEF (Uniform Energy Factor) 4 4
Energy use per year (kWh) 1,240 1,240
First hour rating (gal) 91 91
Rated storage volume (gal) 74 75
Installed cost range $3,993–$4,924 $4,026–$4,933
ENERGY STAR certified not matched yes
Sound level (dB) not filed 49
Refrigerant not filed R-134a, GWP 1430
On the market since not filed 2026-06-30
DOE CCD · 2026-09-19

What it costs to run

Enter your ZIP to price both units on the same rate where you live.

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 Mits Air US3-RSJ-15/300RDVN3-L3 if its price or availability suits you — on energy the two are level.
  • Pick the RINNAI REHP80W if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Mits Air US3-RSJ-15/300RDVN3-L3.
  • Neither if your household's busiest hour needs more than 91 gallons of hot water — neither lists more. Check whether a 75-gallon heater is enough.

Each model on its own

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