Model specs
REHP50C
Rinnai / 46-Gallon Heat Pump Water Heater
Lower running cost than standard electric, but height, 240V, and condensate still decide fit.
UEF3.75Certified efficiency
First hour73 galHot water delivery
Height66.4"Primary fit constraint
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
REHP50C operating cost
This unit saves roughly $448 every year compared to the standard electric tank it replaces
REHP50C
$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.
REHP50C in the 50-gallon heat pump class: #None of 8 on efficiency.
Should this be on your shortlist?
Best for
10-year tank warranty (class-leading)
- Why it makes shortlists: stands out on 10-year tank warranty (class-leading)
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" tallThe bill may work. Now check what actually changes on install day before you let the shortlist settle.
Switching to the REHP50C
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.
REHP50C installation specifications
Dimensions
Height66.4 in
Width21.7 in
Electrical
Voltage240V
Amperage24A
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.
Warranty
Coverage
Tank10 yr
Parts10 yr
Labor1 yr
Class rankings: 50-gallon heat pump water heaters
Rankings
Efficiency (UEF) higher is better
1
Bradford White RE2HP...
2
Rheem PROPH50 T2 RH4...
3
Navien NWP500S050AUMB
4
A. O. Smith HPTS-50-2
5
Rinnai REHP50BM
6
A. O. Smith HPTA-50-2
7
Noritz NHP50
8
Bradford White RE2H50S
Height shortest to tallest
1
Bradford White RE2HP...
2
Noritz NHP50
3
Bradford White RE2H50S
4
Rheem PROPH50 T2 RH4...
5
A. O. Smith HPTA-50-2
6
A. O. Smith HPTS-50-2
7
Navien NWP500S050AUMB
8
Rinnai REHP50BM
First Hour Rating higher means more hot water
1
Rinnai REHP50BM
2
Rheem PROPH50 T2 RH4...
3
A. O. Smith HPTA-50-2
4
A. O. Smith HPTS-50-2
5
Bradford White RE2H50S
6
Bradford White RE2HP...
7
Navien NWP500S050AUMB
8
Noritz NHP50
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 REHP50C
From manufacturer specs, EIA energy data, and DOE regulations.
How much does the REHP50C 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 REHP50C 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 REHP50C fit in my space?
66.4" tall, 21.7" wide. Measure your space including clearances before ordering.
Does the REHP50C 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 REHP50C come with?
10-year tank warranty, 10-year parts. Register with Rinnai after installation to activate full coverage.
Is the REHP50C 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 | |
| UEF | 3.75 |
|---|---|
| First Hour Rating | 73 gal |
| kW Input | 4.9 kW |
| Draw Pattern | Medium |
| Est. Annual Energy | 844 kWh/yr |
| Capacity | |
| Storage Volume | 46 gal |
| Physical | |
| Height | 66.4 in |
| Width | 21.7 in |
| Electrical | |
| Voltage | 240 V |
| Amperage | 24 A |
| Heat Pump | |
| Type | 240 Volt Integrated HPWH |
| Min Ambient | 37.4 °F |
| Max Ambient | 107.6 °F |
| Refrigerant | R-134a |
| Sound Level | 49 dBA |
| Warranty | |
| Tank | 10 yr |
| Parts | 10 yr |
| Labor | 1 yr |
| Certifications | |
| ENERGY STAR | Certified |
| Markets | United States, Canada |
Keep the route moving
Other Rinnai models and the full heat pump guide, if this one isn't the right fit.
Sources. ENERGY STAR, Retailer listing, Rinnai. Data compiled March 2026.Methodology
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