Water heater tool review
Rinnai REHP50 Heat Pump Water Heater Review
Buy the Rinnai REHP50 if you have a basement, garage or utility room with air volume to spare and a floor drain nearby, because a uniform energy factor of 3.75 means it delivers roughly three and a half times more heat than it draws in electricity and that is a running cost no gas tank can match. Skip it if the heater lives in a small interior closet, because a heat pump water heater cools and dehumidifies the air it takes heat from and a sealed closet starves it.
Rinnai REHP50 Electric Heat Pump Water Heater, 50 Gallon
about $1,690
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| Spec | Rinnai REHP50 Electric Heat Pump Water Heater, 50 Gallon |
|---|---|
| Capacity | 50 gallons |
| Efficiency | UEF 3.75, Energy Star certified |
| First hour delivery | Up to 73 gallons |
| Suited to | Households of 3 to 4 people with high demand |
| Electrical | 240V / 30A |
| Connections | 3/4 inch MNPT inlet and outlet |
| Refrigerant | R134a |
| Clearance | Zero clearance required on top, back and sides |
| Warranty | 10 year tank, 10 year parts, 1 year labor |
| Grid features | Demand-response enabled for utility peak programs |
Specs come from Rinnai's published product bullets returned by the Creators API. Price is approximate.
What a UEF of 3.75 actually means for your bill
A resistance electric water heater has a uniform energy factor slightly under 1.0, because it converts electricity to heat one for one and loses a little through the tank. A heat pump does not make heat, it moves it, so a UEF of 3.75 means roughly three and a half units of heat for every unit of electricity. In practice that is a large cut in the water heating share of an electric bill, and it is the entire reason to pay more upfront. Where it disappoints is in a cold unconditioned space, because a heat pump has less ambient heat to move and falls back on its resistance elements more often.
The space requirement is the real constraint
Rinnai lists zero clearance on top, back and sides, which is unusually accommodating, but clearance is not the same as air volume. The unit takes heat out of the surrounding air, so it needs a reasonable volume of air to take it from. A basement or an open garage is ideal. A small sealed closet is not, and the fix there is either ducting the unit or louvering the door, which is a conversation to have with your installer before you buy. It also produces condensate continuously, so it needs a drain or a condensate pump.
Heat pump or gas: the comparison that decides it
If you already have gas service, this is a genuine head to head rather than an obvious upgrade, and it turns on local electricity and gas prices plus whatever rebates apply where you live. Our heat pump vs gas water heater cost comparison works through it, and the water heater replacement cost calculator prices the swap for your own tank size. Rebates for heat pump water heaters change frequently and often change the answer outright, so check current local and utility programs before you compare sticker prices.
The 240V circuit, and the panel question
The REHP50 runs on 240V at 30A. If you are replacing a gas tank, that circuit does not exist yet and someone has to run it, which is licensed and permitted electrical work. If you are also adding an EV charger or an electric range, the cumulative load is a panel capacity question rather than a series of independent ones. Price it in the electrical panel upgrade cost calculator and have a licensed electrician run the load calculation, because that calculation is the thing that decides whether your electrification plan is a weekend or a service upgrade. Our gas vs electric water heater cost comparison covers the circuit requirement in more detail.
The honest weakness: it is a fan and a compressor in your house
A heat pump water heater is not silent. It runs a compressor and a fan, and owners of hybrid units across all brands consistently describe the noise as similar to a window air conditioner or a dehumidifier. In a basement nobody notices. Under a bedroom floor, or in a closet off a hallway, people do. It also cools and dries the space it sits in, which is a bonus in a humid basement and a problem in a finished room in winter. Recovery in heat pump mode is also slower than a gas tank, which is why the first hour rating matters more than the tank size when comparing.
What owners consistently report
Across published owner reviews of hybrid heat pump water heaters generally, the consistent themes are large drops in water heating cost, satisfaction with the dehumidifying side effect in basements, and complaints about noise where the unit sits near living space. Installation reports cluster around two things: the condensate drain, which is easy to underestimate, and the electrical circuit, which is where an unplanned expense usually appears.
Who it suits
- Basements, garages and utility rooms with air volume to spare
- Households of three to four with high hot water demand
- All-electric homes and deliberate electrification projects
- Areas with utility rebates or demand-response programs
Who should skip it
- Small sealed closets without ducting or louvered doors
- Locations directly below or beside bedrooms
- Homes with no 240V capacity and no appetite for a panel upgrade
- Very large households needing rapid recovery, where flow-rate matters more
Safety, stated plainly
The 240V / 30A circuit this unit needs is licensed electrical work in most jurisdictions and requires a permit and an inspection. Do not run it yourself and do not have it run by someone who suggests skipping the permit. The tank also needs a correctly piped temperature and pressure relief valve discharging to a safe location, which is a code requirement and a genuine scald and rupture protection, not a formality. Water temperature above about 120 degrees Fahrenheit scalds quickly, which matters in homes with children or older adults.
Alternatives worth comparing
about $1,100
Several hundred dollars less for the same tank size and the same basic technology, worth considering when the rebate you are chasing has a price cap or when the budget is tight.
View on Amazonabout $1,800
A comparable hybrid tank from an HVAC-channel brand, which can be the easier warranty path if your installer already works with that supplier.
View on Amazonabout $1,533
If you have gas service and a large simultaneous demand, a high output condensing tankless unit delivers flow a 50 gallon tank cannot, at the cost of venting and gas line work.
View on AmazonHow we researched this
We did not test the Rinnai REHP50 Electric Heat Pump Water Heater, 50 Gallon in person, and nothing here is written as though we did. This review is drawn from the manufacturer's published specifications, the product's own documentation, and the consensus of published owner reviews, which is summarised as exactly that rather than presented as our own use. Specifications are sourced as noted under the table above, and prices are approximate and move. Cost figures elsewhere on this site are 2026 estimates, not quotes. This is researched information, not professional advice: anything touching electrical, gas, structural, roofing or hazardous material work should go to a licensed professional and through your local permitting process. For the cost side of this decision, see Heat pump water heater vs Gas tank.
Frequently asked questions
How much does a heat pump water heater save?
A UEF of 3.75 means it delivers about three and a half units of heat per unit of electricity, against slightly under 1.0 for a resistance electric tank. That is a large cut in the water heating portion of an electric bill. Against gas the answer depends entirely on local electricity and gas prices, which is why the comparison has to be run with your own rates.
Can a heat pump water heater go in a closet?
Only if the closet is ducted or has a louvered door. The unit extracts heat from surrounding air, so a small sealed space starves it and pushes it onto its resistance elements, which removes most of the efficiency you paid for. Rinnai lists zero clearance on top, back and sides, but clearance and air volume are different requirements.
Is a heat pump water heater noisy?
It runs a compressor and a fan, and owners typically describe the sound as comparable to a dehumidifier or a window air conditioner. In a basement or garage that is a non-issue. Directly under a bedroom it can be, so consider the location before the specification.
What electrical circuit does the Rinnai REHP50 need?
It operates on 240V at 30A. If you are replacing a gas water heater, that circuit almost certainly does not exist and a licensed electrician needs to run it under permit. If you are adding other electric loads such as an EV charger at the same time, have the electrician run a whole-house load calculation rather than treating each addition separately.
Do I need a drain for a heat pump water heater?
Yes. The unit produces condensate continuously as it cools the surrounding air, so it needs a gravity drain or a condensate pump. This is one of the most commonly overlooked parts of the installation and one of the most common causes of an unexpected extra cost on the day.