Rinnai REHP50

ENERGY STAR certified

Heat pump water heater · 46 gallons

InYour statethis water heater costs

about $13 a month

$152 a year

An estimate at your state's average rate — not a guarantee of your bill.

Estimated yearly cost

$118

a year

The yellow sticker says $118 a year.

You'll pay $34 more.

Sticker uses 14¢ per kWh. The U.S. average is 18.0¢ per kWh.

Energy use

844 kWh a year

vs similar heat pump water heater

-25%

Cheaper water heaters, same size

ENERGY STAR lists 2 other certified models at the same 844 kWh a year, size and type, so everything on this page applies to them too.

Cheaper to run, same size

A year at the U.S. average residential rate.

Compare all 184 water heaters 45–55 gallons

Cost in every state

844 kWh a year × each state's average residential rate (EIA 12-month average through July 2026).

State	Rate	Per year	Per month
Hawaii	43.7¢	$369	about $31 a month
California	33.1¢	$280	about $23 a month
Massachusetts	30.4¢	$256	about $21 a month
Rhode Island	29.4¢	$248	about $21 a month
Maine	29.3¢	$247	about $21 a month
New York	28.4¢	$239	about $20 a month
Connecticut	28.2¢	$238	about $20 a month
Alaska	27.0¢	$228	about $19 a month
New Hampshire	26.8¢	$226	about $19 a month
District of Columbia	24.2¢	$204	about $17 a month

Show all 52 states

Vermont	23.9¢	$202	about $17 a month
New Jersey	23.6¢	$199	about $17 a month
Maryland	22.3¢	$188	about $16 a month
Michigan	21.0¢	$177	about $15 a month
Pennsylvania	20.8¢	$175	about $15 a month
Illinois	19.0¢	$160	about $13 a month
Wisconsin	18.8¢	$158	about $13 a month
Ohio	18.3¢	$154	about $13 a month
U.S. average	18.0¢	$152	about $13 a month
Delaware	18.0¢	$152	about $13 a month
Indiana	17.1¢	$144	about $12 a month
Virginia	16.6¢	$140	about $12 a month
Colorado	16.6¢	$140	about $12 a month
Alabama	16.5¢	$139	about $12 a month
Minnesota	16.2¢	$137	about $11 a month
Texas	16.0¢	$135	about $11 a month
South Carolina	15.7¢	$133	about $11 a month
West Virginia	15.7¢	$132	about $11 a month
Oregon	15.6¢	$131	about $11 a month
Arizona	15.5¢	$131	about $11 a month
Florida	15.4¢	$130	about $11 a month
New Mexico	15.2¢	$129	about $11 a month
Kansas	15.1¢	$128	about $11 a month
Georgia	15.1¢	$127	about $11 a month
Mississippi	14.9¢	$126	about $11 a month
North Carolina	14.9¢	$126	about $10 a month
South Dakota	14.3¢	$120	about $10 a month
Washington	14.2¢	$120	about $10 a month
Wyoming	14.2¢	$119	about $10 a month
Iowa	14.1¢	$119	about $10 a month
Kentucky	14.0¢	$118	about $10 a month
Montana	13.9¢	$118	about $10 a month
Missouri	13.9¢	$117	about $10 a month
Tennessee	13.7¢	$115	about $10 a month
Oklahoma	13.6¢	$115	about $10 a month
Nevada	13.6¢	$114	about $10 a month
Arkansas	13.5¢	$114	about $9 a month
Utah	13.3¢	$112	about $9 a month
Louisiana	13.1¢	$110	about $9 a month
Nebraska	12.9¢	$109	about $9 a month
Idaho	12.7¢	$107	about $9 a month
North Dakota	12.5¢	$106	about $9 a month

What the Rinnai REHP50 costs where electricity is expensive

At Hawaii's average residential rate of 43.7¢ per kWh, the Rinnai REHP50 costs $369 a year — $251 more a year than the label says. The EnergyGuide label estimates $118 a year, because every label in the country is calculated at 14¢ per kWh. At the U.S. average of 18.0¢ per kWh this water heater costs $152 a year, and in North Dakota, the cheapest state, $106 a year.

Estimated annual running cost for the Rinnai REHP50 in the highest-rate states and the lowest-rate state
Where	Rate	Cost a year	vs the label
Hawaii	43.7¢ per kWh	$369	+$251
California	33.1¢ per kWh	$280	+$161
Massachusetts	30.4¢ per kWh	$256	+$138
Rhode Island	29.4¢ per kWh	$248	+$130
Maine	29.3¢ per kWh	$247	+$129
North Dakota	12.5¢ per kWh	$106	−$12

Electricity prices: EIA 12-month average through July 2026, residential sector, average revenue per kWh. Label figure calculated at 14¢ per kWh, the rate the FTC requires on labels.

Full specs

At the U.S. average residential rate this one costs $152 a year — about 25% cheaper to run than the average heat pump water heater ($203 a year across 510 certified models).

$152

Most efficient $123Average $203Least efficient $314

Every model on this scale is ENERGY STAR certified. Range across 510 heat pump water heaters, priced a year at the U.S. average residential rate.

Brand: Rinnai
Model number: REHP50
Type: Heat pump water heater
Capacity: 46 gallons
Annual energy use: 844 kWh a year
Combined Energy Factor (CEF): 3.75
ENERGY STAR Most Efficient: No
On the market since: August 2024
Certified: March 2026
Tank volume (gallons): 46
First-hour rating (gallons): 73
Uniform Energy Factor (UEF): 3.75
Draw pattern: Medium-Usage
Heat pump type: 240 Volt Integrated HPWH
Recovery efficiency (%): 465.00
Tank height (in): 66.4
Tank diameter (in): 21.7

Where to buy

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Common questions

+How much does the Rinnai REHP50 cost to run per month?

about $13 a month at the U.S. average residential rate of 18.0¢ per kWh, or $152 a year. Your cost depends on your state's rate — see the table above.

+How many kWh does the Rinnai REHP50 use?

844 kWh a year, as the manufacturer filed it with the EPA, in the ENERGY STAR certified product database.

+Is the Rinnai REHP50 energy efficient?

It is listed as ENERGY STAR certified. It uses about 25% less electricity than the average heat pump water heater (average: 1,123 kWh a year).

+How does the Rinnai REHP50 compare to the average water heater?

The average heat pump water heater in our database uses 1,123 kWh a year, costing $203 a year at the U.S. average residential rate. The Rinnai REHP50 uses 844 kWh a year, costing $152 a year.

How we calculate this

Annual energy use (844 kWh a year) is the figure the manufacturer filed for this model with the EPA, in the ENERGY STAR certified product database. Running cost is that figure multiplied by a state's average residential electricity price from the U.S. Energy Information Administration (12-month average through July 2026, average revenue per kWh).

The annual figure for a water heater assumes a hot water draw of 10, 38, 55 or 84 gallons a day, set by the heater's first-hour rating, per the DOE test procedure (10 CFR 430 Subpart B, Appendix E). Full methodology.

Sources: EPA ENERGY STAR certified product data, updated weekly · U.S. EIA electricity prices, 12-month average through July 2026.