Rinnai REHP50 Heat Pump Water Heater Review

The listing publishes the same three facts as the rest of this category: 50 gallons of storage, an electric heat pump fuel type, and an Energy Star certification. It does not publish the compressor's input, the backup elements' wattage, the measured UEF, the measured first hour rating, the required voltage, or the dimensions. Rinnai also sells this tank at 65 and 80 gallons for larger households, listed separately with their own specification pages.

This suits a household that has already decided on a heat pump water heater and is choosing between manufacturers rather than deciding whether the category makes sense at all. It suits a buyer who values a residential service network already built for a different Rinnai product line, on the reasoning that a compressor failure in year eight or nine is easier to resolve when the manufacturer already dispatches technicians for tankless service calls in the same region. It suits a mechanical space with roughly 700 cubic feet of surrounding air or equivalent ducting, and a place for a condensate line to go.

Skip this if the mechanical space cannot supply the air volume a heat pump water heater needs, or if the space regularly runs near freezing, since heat pump water heaters as a category lose efficiency and can lock out below a manufacturer-specified ambient minimum. Skip it if the household's real goal is the lowest purchase price into the category, since the Senville option in this same catalog covers that at a meaningfully lower entry cost with the same Energy Star certification.

And if the honest need is simply a fast replacement for a failed tank today, a plain electric resistance tank from a home center with installation included is often cheaper and quicker, and that remains a reasonable choice. The service-channel argument for this tank only pays off over years of ownership, not on install day.

Expect the same cross-trade installation as any heat pump water heater: electrical for a circuit sized to the nameplate, plumbing for the water connections and the T&P discharge, and a condensate line routed to a floor drain or a pump. Use the nameplate amperage, not an assumption, with the breaker size calculator. Expect the room to run somewhat cooler and drier while the compressor runs, and expect an audible compressor hum comparable to a small dehumidifier.

This crosses enough trades and touches enough of a factory refrigerant charge that it belongs to a licensed installer. Labor cost estimates for the swap live at houseprojectcalc.com, not here.

We did not test, install or measure this water heater ourselves. This review draws on the manufacturer's own listing, the Energy Star certification process a unit must pass to carry that label, the installation requirements published across the heat pump water heater category generally, and the consensus pattern in verified owner reviews, including comments on Rinnai's existing service presence for its other product lines. Where the listing does not publish a figure for this specific model, we say so rather than estimate one.

Same closed-system and condensate realities as any heat pump water heater, with one addition: a household paying more for an established service channel is usually also the household that wants an automatic shutoff rather than a passive sensor.