Best Heat Pump Water Heaters (2026)

The REHP65 is the most balanced unit in this guide. A 65 gallon tank with a 4.00 UEF and an Energy Star listing puts it at the efficient end of the field, and a first hour rating of up to 80 gallons covers the peak demand of a household of about four or five people, which is when the morning showers, a dishwasher and a washing machine overlap.

UEF, the uniform energy factor, is the federal efficiency number. A standard electric tank is roughly 0.9 and a heat pump unit like this is about four times higher, which is why the running cost drops so sharply. First hour rating is the other number that matters: it is how much hot water the heater can deliver in the first hour of heavy use, and it decides whether you run out in the shower.

The unit is demand-response enabled, meaning it can communicate with a utility to shift energy use away from peak hours. It needs a 240 volt, 30 amp circuit, which is an electrician job if you are replacing a gas heater. Plan for the condensate drain, adequate air volume around the unit and a quarterly cleaning of the air filter. In year three, expect to clean the air filter several times, flush the tank once a year and check the anode rod, since a heat pump unit has more parts than a plain tank but the same sacrificial anode. Water quality matters here: hard water builds scale on the lower element in hybrid mode, so a water softener or periodic flushing protects it. Keep the area around the unit clear so the intake and exhaust do not recirculate.

The REHP80 is the larger sibling of the REHP65: an 80 gallon tank with the same 4.00 UEF and a first hour rating of up to 91 gallons. It is aimed at households of five or more, homes with several bathrooms or those with a large soaking tub, where a smaller tank would run out.

The jump from 65 to 80 gallons adds 15 gallons of storage and 11 gallons of first hour delivery. That may not sound like much, but in the peak hour it is the difference between a fifth shower and a cold one. A bigger tank also means a larger footprint and more weight when full, so check the floor, the ceiling height and the stairs on the way to the install location.

Like the REHP65, it needs a 240 volt, 30 amp circuit and is demand-response enabled. If your household is smaller, the REHP65 delivers the same efficiency with a smaller tank and a lower upfront cost. A tank this size is heavy when full, roughly 700 pounds of water and steel, so confirm the floor and the stair path before delivery. Because the unit cools the surrounding air, a large utility room or garage is ideal, and a ducted installation can send the cool exhaust outdoors instead of chilling the house. Put in a drain pan and a leak sensor under the tank, as you would for any large tank.

The Senville is a 50 gallon hybrid heat pump with a 3.75 UEF, a 69 gallon first hour rating, Energy Star certification and UL and AHRI listings. A 50 gallon tank suits a household of two to four people, a common size that fits the footprint of most standard heaters.

Its 3.75 UEF is a bit below the Rinnai units' 4.00, which means slightly higher running costs, but it is still far more efficient than a standard electric tank. The hybrid design includes backup electric elements, so if you hit a heavy demand the unit can supplement the heat pump to recover faster.

A 69 gallon first hour rating is lower than the Rinnai REHP65's 80 gallons, so it will run out sooner in a busy house. It is a good fit for a smaller household that wants the efficiency savings without the larger tank. Plan for the same air volume, drain and electrical requirements as the others. Because it has a lower UEF than the Rinnai units, the Senville uses slightly more electricity for the same hot water, which is worth running through the numbers with your local electricity rate. In a smaller household it still saves a large share of the cost of a standard electric tank. Check the warranty terms on both tank and compressor, since the compressor is the part that costs most to replace.

The ACiQ 50 gallon unit is a hybrid heat pump with WiFi control and a stated operating noise of 49.5 dBA, about the level of a quiet conversation or a dehumidifier. For a basement or garage next to living space, that is a significant factor, since the fan and compressor are the main sources of noise in this category.

The listing is explicit about installation: it is for indoor use only, performs best in stable indoor temperatures, should not be installed in unheated spaces that fall below a minimum and needs 700 to 1,000 cubic feet of air around it. That air volume requirement is typical of heat pump water heaters and is why a closet is a poor location unless it is ducted.

Compared with the Senville, the ACiQ adds WiFi and a stated noise figure at the same 50 gallon size. It does not list a UEF in the data we have, so check the EnergyGuide label for the efficiency before you buy. Fit a condensate drain and keep the intake clear. For a unit that listens to your phone, WiFi control is useful for vacation mode and for scheduling, and some units report error codes that help a plumber diagnose a problem quickly. The stated 49.5 dBA is a manufacturer figure, so read the manual for the operating range and install it away from bedrooms. Confirm the UEF on the EnergyGuide label, since the listing in our data does not give it, and make sure the condensate line has a slope toward the drain.