RatingPlate Find your size
Browse the site

Type guides, state costs, model specs, and brand pages.

Heater Types

Heat Pump Water HeatersHigh-efficiency electric replacements and hybrid tanks.Condensing Tankless Water HeatersCondensing whole-home flow with venting constraints.Gas Tank Water HeatersStraight swaps when gas storage is still the fit.

Plan Your Swap

Sizing guideCapacity, first-hour rating, and temperature-rise fit.Accessories hubInstall extras, code-adjacent parts, and paid-link accessory picks.Upgrade from NHP50Replacement candidates and projected operating-cost delta.Upgrade from NHP65Replacement candidates and projected operating-cost delta.Upgrade from NHP80Replacement candidates and projected operating-cost delta.Upgrade from NPE 210S2Replacement candidates and projected operating-cost delta.Upgrade from PROE50 T2 RH95Replacement candidates and projected operating-cost delta.HPTA 50 2 vs HPTA 80 2Side-by-side specs, efficiency, and fit differences.HPTS 50 2 vs NHP50Side-by-side specs, efficiency, and fit differences.NHP120 vs PROPH80 T2 RH400 30Side-by-side specs, efficiency, and fit differences.NPE 210S2 vs NPE 240S2Side-by-side specs, efficiency, and fit differences.

Guides & Data

California heat pump guideLocal rates, rebates, and operating costs.Colorado heat pump guideLocal rates, rebates, and operating costs.Massachusetts heat pump guideLocal rates, rebates, and operating costs.Oregon heat pump guideLocal rates, rebates, and operating costs.Washington heat pump guideLocal rates, rebates, and operating costs.DOE 2029 standardsWhat changes in 2029 and which product classes move first.

Brands

A.O. Smith Water HeatersPublished models, product lines, and brand coverage.Bradford White Water HeatersPublished models, product lines, and brand coverage.Navien Water HeatersPublished models, product lines, and brand coverage.Noritz Water HeatersPublished models, product lines, and brand coverage.Rheem Water HeatersPublished models, product lines, and brand coverage.Rinnai Water HeatersPublished models, product lines, and brand coverage.Takagi Water HeatersPublished models, product lines, and brand coverage.
Model specs

REHP50BM

Rinnai / 46-Gallon Heat Pump Water Heater
Lower running cost than standard electric, but height, 240V, and condensate still decide fit.
ShortlistRunning costInstall changeFull specs
UEF3.75Certified efficiency
First hour73 galHot water delivery
Footprint66.4" × 22"Height × depth
Running cost~$146/yrU.S. average electricity
Estimated annual savings: $448 compared to a standard standard electric tank. Based on U.S. average energy prices. See all heat pump models

REHP50BM operating cost

This unit saves roughly $448 every year compared to the standard electric tank it replaces
REHP50BM
$146/yr
Std tank (0.92 UEF)
$593/yr
~2.7year payback
At $448/yr in savings, the upfront premium pays for itself in about 2.7 years. Over 10 years: roughly $3,280 in net savings.
Your state changes the math. Annual cost ranges from ~$93/yr (ND) to ~$351/yr (HI).
U.S. avg electricity: $0.17/kWh (EIA, Dec 2025). The federal tax credit of up to $2,000 under IRA Section 25C expired December 31, 2025. State and utility rebates may still apply.
REHP50BM in the 50-gallon heat pump class: #5 of 8 on efficiency.

Should this be on your shortlist?

Best for

10-year tank warranty (class-leading)

Not ideal for

tallest in class

  • Why it makes shortlists: solid mid-class efficiency (#5 of 8)
Shortlist alternatives in 50-gallon heat pump:
Bradford White RE2HP50-1NCTTUEF 3.89 · 46.1" tallRheem PROPH50 T2 RH400-30UEF 3.88 · 61.8" tallNavien NWP500S050AUMBUEF 3.85 · 63" tall
Check price and availability: Rinnai REHP50BM on Amazon
The bill may work. Now check what actually changes on install day before you let the shortlist settle.

Switching to the REHP50BM

From a standard electric tank

✓
Same voltage (240V). Verify breaker size matches unit requirements (30A typical).
▲
Taller unit (66.4"). Measure overhead clearance.
▲
Condensate drain needed. Floor drain or condensate pump.
▲
Air space needed around the unit for heat exchange.
Fewest install changes of any upgrade path. Scope depends on existing wiring, clearances, and condensate routing.

From a gas tank

▲
New 240V/30A circuit required. Hire an electrician.
✓
Gas line capped. No more gas bill for hot water.
✓
Existing flue/vent can be removed.
▲
Condensate drain needed.
Two trades needed (plumber + electrician).

From an older heat pump

✓
Same electrical. Same condensate drain.
▲
Check height. This unit is 66.4" tall.
✓
Standard water connections.
Similar installation profile. Verify dimensions, clearances, and condensate routing match your existing setup.
Height, electrical service, condensate, and noise. These are the four things that determine whether a heat pump fits your space and your quote.

REHP50BM installation specifications

Dimensions

Height66.4 in
Width21.7 in
Depth22 in
Weight212 lbs
Connections3/4 inch NPT

Electrical

Voltage240V
Amperage24A
Breaker30A dedicated

Heat Pump

Min ambient temp37.4°F
Max ambient temp107.6°F
RefrigerantR-134a
Noise49 dBA

Common install considerations for heat pump units

What is required depends on your existing installation, local code, and installer preference.

Thermal Expansion Tank Often required by code Check on Amazon (paid link)
Water Heater Drain Pan Often required by code Check on Amazon (paid link)
Earthquake Straps (Seismic Restraints) Often required by code Check on Amazon (paid link)
Full accessories list

Warranty

Coverage

Tank10 yr
Parts10 yr
Labor1 yr
Class rankings: 50-gallon heat pump water heaters

Rankings

Efficiency (UEF) higher is better
#5of 8Efficiency
1
Bradford White RE2HP...
3.89
2
Rheem PROPH50 T2 RH4...
3.88
3
Navien NWP500S050AUMB
3.85
4
A. O. Smith HPTS-50-2
3.8
5
Rinnai REHP50BM
3.75
6
A. O. Smith HPTA-50-2
3.68
7
Noritz NHP50
3.46
8
Bradford White RE2H50S
3.44
Height shortest to tallest
#8Last in ClassCompactness · 8 models tested
1
Bradford White RE2HP...
46.1"
2
Noritz NHP50
58.3"
3
Bradford White RE2H50S
59.1875"
4
Rheem PROPH50 T2 RH4...
61.75"
5
A. O. Smith HPTA-50-2
63"
6
A. O. Smith HPTS-50-2
63"
7
Navien NWP500S050AUMB
63"
8
Rinnai REHP50BM
66.4"
First Hour Rating higher means more hot water
#1Class LeaderHot Water Delivery · 8 models tested
1
Rinnai REHP50BM
73 gal
2
Rheem PROPH50 T2 RH4...
67 gal
3
A. O. Smith HPTA-50-2
65 gal
4
A. O. Smith HPTS-50-2
65 gal
5
Bradford White RE2H50S
65 gal
6
Bradford White RE2HP...
65 gal
7
Navien NWP500S050AUMB
65 gal
8
Noritz NHP50
58 gal
⚡
Starting May 2029, new federal standards require heat pump technology for electric water heaters over 35 gallons. Electric tanks 35 gal and under can still use resistance elements. Every heat pump on this list already exceeds the future standard. Read the full DOE 2029 analysis

Common questions about the Rinnai REHP50BM

From manufacturer specs, EIA energy data, and DOE regulations.

How much does the REHP50BM cost to run per year?
~$146/yr at the U.S. average electricity rate. That is roughly $448/yr less than a standard electric tank.
How much hot water does the REHP50BM deliver?
73 gallons in the first hour from a 46-gallon tank. Suitable for a household of 1 to 3 people at medium draw.
Will the REHP50BM fit in my space?
66.4" tall, 21.7" wide, 22" deep. Measure your space including clearances before ordering.
What electrical circuit does the REHP50BM need?
240V, 30A dedicated circuit. Check your electrical panel before installation.
Does the REHP50BM work in cold climates?
The heat pump operates down to 37.4°F ambient temperature. Below that, it switches to standard electric resistance mode, losing the efficiency advantage. In cold climates, install inside the heated building envelope, not in an unheated garage.
What warranty does the REHP50BM come with?
10-year tank warranty, 10-year parts. Register with Rinnai after installation to activate full coverage.
Is the REHP50BM eligible for rebates?
ENERGY STAR certified heat pump water heater. The federal tax credit (IRA Section 25C, up to $2,000) expired December 31, 2025. State and utility rebates may still apply depending on your location.
Is this unit future-proof under the 2029 DOE standards?
Yes. Starting May 2029, electric water heaters over 35 gallons must use heat pump technology. This unit already exceeds that standard.
Full specifications
Performance
UEF3.75
First Hour Rating73 gal
kW Input4.9 kW
Draw PatternMedium
Est. Annual Energy844 kWh/yr
Capacity
Storage Volume46 gal
Physical
Height66.4 in
Width21.7 in
Depth22 in
Weight212 lbs
Connections3/4 inch NPT
Electrical
Voltage240 V
Amperage24 A
Breaker30A dedicated
Heat Pump
Type240 Volt Integrated HPWH
Min Ambient37.4 °F
Max Ambient107.6 °F
RefrigerantR-134a
Sound Level49 dBA
Warranty
Tank10 yr
Parts10 yr
Labor1 yr
Certifications
ENERGY STARCertified
MarketsUnited States, Canada
Keep the route moving

Other Rinnai models and the full heat pump guide, if this one isn't the right fit.

Head-to-head comparisons
Heat Pump guideAll Rinnai modelsSizing guideInstallation accessoriesAll models
Sources. ENERGY STAR, Lowe's, Retailer listing, Rinnai. Data compiled March 2026.Methodology
As an Amazon Associate I earn from qualifying purchases. RatingPlate may earn a commission when you use qualifying Amazon links. Links to Amazon are marked "(paid link)". We never display prices because Amazon prohibits showing prices outside their platform.