WattCost

Data through June 2026

Running cost · Water Heaters (Electric) · ENERGY STAR certified

Rinnai REHP50BM

Heating a typical household's hot water, the Rinnai REHP50BM is certified at 844 kWh a year — about $155 at the U.S. average electricity rate, or $12.90 a month. Only a handful of certified electric water heaters do better: it ranks 28 of 510 and undercuts the median by 30%. Where you live moves the bill from $111 a year in Nevada to $445 in Hawaii.

Dimensions 66.4" H × 21.7" W

Estimated annual running cost · U.S. average rate 18.3¢/kWh

$155/yr

$125 · cheapest certified water heaters (electric)$319 · priciest
Per month
$12.90
Per day
42¢
Certified use
844 kWh/yr
Type
Hybrid/Electric Heat Pump
Heat pump type
240 Volt Integrated HPWH
Storage volume
46 gal
First-hour rating
73 gal
UEF
3.75
681 kWh1,741 kWh
Where the Rinnai REHP50BM (▮) sits among all 510 certified water heaters (electric), by annual kWh

What it costs in every state

Rinnai REHP50BM: 844 kWh/yr × each state's average residential rate (EIA)
StateRate ¢/kWhThis model $/yrRelative cost
Alabama16.4¢$138
Alaska28.2¢$238
Arizona15.2¢$128
Arkansas14.1¢$119
California34.7¢$293
Colorado17.1¢$145
Connecticut24.3¢$205
Delaware19.3¢$163
District of Columbia24.4¢$206
Florida15.1¢$127
Georgia16.4¢$138
Hawaiipriciest52.7¢$445
Idaho14.4¢$121
Illinois19.9¢$168
Indiana17.5¢$148
Iowa15.9¢$134
Kansas15.7¢$133
Kentucky14.3¢$120
Louisiana13.5¢$114
Maine29.6¢$250
Maryland21.8¢$184
Massachusetts29.6¢$250
Michigan23.0¢$194
Minnesota17.5¢$148
Mississippi14.9¢$126
Missouri16.2¢$137
Montana15.1¢$128
Nebraska13.3¢$112
Nevadacheapest13.1¢$111
New Hampshire27.0¢$228
New Jersey24.9¢$211
New Mexico15.1¢$127
New York29.5¢$249
North Carolina14.7¢$124
North Dakota14.1¢$119
Ohio19.2¢$162
Oklahoma14.3¢$121
Oregon16.3¢$138
Pennsylvania21.7¢$183
Rhode Island29.2¢$247
South Carolina15.6¢$131
South Dakota15.4¢$130
Tennessee14.1¢$119
Texas15.9¢$135
Utah13.4¢$113
Vermont24.4¢$206
Virginia17.2¢$145
Washington14.9¢$126
West Virginia15.4¢$130
Wisconsin19.6¢$165
Wyoming15.2¢$129

Certified models closest in efficiency

electric water heaters within reach of 844 kWh/yr
ModelkWh/yr$/yr (US avg)
Rinnai REHP50844$155
Rinnai REHP50C844$155
Friedrich PROH50 T2 FD400-30846$155
Friedrich PROH50 T2 FD400-SO846$155
Rheem PROPH50 T2 RH375-30846$155
Rheem PROPH50 T2 RH400-30846$155

Run your own numbers

Your rate, your numbers

Per day
42¢
Per month
$12.90
Per year
$155

844 kWh/yr × 18.3¢/kWh = $155/yr

Prefilled with this model's certified 844 kWh/yr — adjust if your usage differs from the DOE test basis. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.

Questions, answered with the data

How much electricity does the Rinnai REHP50BM use?
ENERGY STAR certifies the Rinnai REHP50BM at 844 kWh per year. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.
How much does the Rinnai REHP50BM cost to run per month?
About $12.90 a month at the U.S. average residential rate (18.3¢/kWh) — 42¢ a day, or $155 a year. Your state's rate moves this up or down; see the table above.
Is the Rinnai REHP50BM energy efficient?
It uses 30% less electricity than the median certified electric water heater, placing it in the top 10% of certified models.
What does the Rinnai REHP50BM cost to run in the cheapest vs. priciest state?
At current residential rates it costs about $111 a year in Nevada (13.1¢/kWh) and $445 in Hawaii (52.7¢/kWh).

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