Heat Pump Water Heater vs Traditional After One Year of Real Data

A year ago I pulled out my old 50-gallon natural gas water heater and replaced it with a Rheem ProTerra 65-gallon heat pump water heater. The gas unit worked fine. It was twelve years old and due for replacement anyway, so I decided to jump to the heat pump version instead of dropping in another gas tank. I kept a spreadsheet for twelve months. Here is everything I learned.

What It Cost to Buy and Install

The Rheem ProTerra ran $1,800 at a plumbing supply house. Installation was $400, which was lower than I expected. The plumber needed about four hours. Most of that time went to running a condensate drain line, since heat pump water heaters pull moisture from the air and produce condensation the same way a dehumidifier does. My basement had a floor drain eight feet away, so the line was short. If your install location doesn't have a nearby drain, expect to add a condensate pump for another $80 to $120.

The electrical hookup was straightforward because I had an open 30-amp breaker slot near the install location. Someone with a full panel or a long run from the breaker box could pay $300 to $600 more for electrical work. All in, I spent $2,200 before any rebates.

The IRA Rebate Situation

Heat pump water heaters qualify for a federal tax credit of up to $2,000 under the existing 25C Energy Efficient Home Improvement Credit. There is also the HEAR program, which stands for Home Efficiency Rebates, offering qualifying households up to $1,750 as a point-of-sale rebate. The catch is that HEAR availability depends on your state rolling out its allocation, and as of early 2026, not every state had the program running. I filed for the 25C tax credit instead and got $1,800 back on my federal return. Either path works, but check what your state offers before you buy, because combining the two isn't allowed for the same purchase.

Monthly Energy Costs Compared

On the old gas water heater, my gas bill included a line item I could roughly isolate for hot water. Summer months ran about $22. Winter climbed to $28 or $30 because incoming water was colder. Across twelve months, hot water on gas cost me roughly $300, which works out to $25 a month on average.

The heat pump water heater has been running for a full year now and I tracked the electricity usage with a $30 energy monitor on the circuit. Summer months came in around $8 to $10. Winter months hit $14 to $16 because the unit pulls heat from the surrounding air and there is less warmth available in a cool basement during January. The twelve-month total was $143, or about $12 a month. That is a savings of roughly $157 per year.

At $157 per year against an out-of-pocket cost of $2,200, the simple payback before rebates would be about 14 years. With the $1,800 tax credit factored in, the effective cost drops to $400 and the payback is under three years. The rebate does the heavy lifting on the economics.

How the Three Modes Work

The ProTerra has three operating modes, and understanding them matters because they affect both your energy costs and how fast you get hot water.

Heat pump only mode is the most efficient setting. The unit runs its compressor to pull heat from the surrounding air and transfer it into the water tank. This is where the $12 per month number comes from. The tradeoff is recovery time. When my household uses a lot of hot water in a short window, like back-to-back showers plus a dishwasher cycle, this mode takes two to three hours to bring the tank back up to temperature. On a gas heater, the same recovery happened in about 40 minutes.

Hybrid mode uses both the heat pump compressor and the electric resistance heating elements. It's the default setting and what Rheem recommends for most households. In practice it runs the heat pump for normal demand and kicks on the resistance elements when it detects a large temperature drop in the tank. My energy costs in hybrid mode were about $2 to $3 per month higher than heat pump only, but recovery time improved significantly. I ran the first three months in hybrid and the rest in heat pump only after adjusting my routine around the slower recovery.

Electric resistance mode bypasses the heat pump entirely and runs the tank like a traditional electric water heater. Energy costs jumped to about $35 per month in this mode, which is actually worse than gas. The only reason to use it is if the compressor fails and you need hot water while waiting for a repair, or if ambient temperature drops below about 40F. I tested it for one week to get a baseline and switched back.

The Noise Problem

Nobody talks about this enough. The heat pump compressor runs at about 49 to 51 decibels, roughly the volume of a running refrigerator, except it runs for much longer stretches. When the tank is recovering, the compressor can go for two hours straight. In a basement with a closed door above, I barely notice it. But I spent one afternoon working in the basement near the unit and the persistent hum became obvious within 30 minutes.

If your water heater lives in a utility closet on the main floor, or in a garage that shares a wall with a bedroom, the noise will be a factor. I would not install one of these in any location where someone sleeps or works nearby. The basement or a detached garage are the best spots. Mine got slightly quieter around month four, but it was a subtle change.

The Room Cooling Effect

Because the heat pump pulls heat from the surrounding air, it cools the space it sits in. My basement runs about 65F in summer without any air conditioning. With the water heater running, the area within ten feet of the unit drops to 60 or 61F. In July and August, that felt like a bonus.

In winter, the dynamic reverses. My basement dropped to about 55F during the coldest months, 3 to 4 degrees colder than it used to be with the gas heater. That cold air doesn't stay contained to the basement either. My first-floor rooms were slightly cooler, which meant my furnace ran a bit more. The $157 in water heating savings might lose $30 or $40 to extra furnace runtime. The net benefit is still positive, but it is not as clean as the water heater number in isolation suggests.

Tank Size and Recovery Planning

I went from 50 gallons on gas to 65 gallons on the heat pump, and I'd recommend the same to anyone making this switch. The larger tank acts as a buffer against the slower recovery time. With 65 gallons stored, my household of three can get through a normal morning without running out. Two showers and a dishwasher load leaves the tank about 60% depleted, and it recovers fully in about two hours on heat pump only mode.

If I had gone with a 50-gallon heat pump model, the math would be tighter. Two showers would drop it to maybe 30% remaining, and a third person would be gambling on lukewarm water. The price difference between the 50 and 65 gallon ProTerra was only about $150, so the upsizing was worth every dollar.

One Year Verdict

The heat pump water heater works well and I don't regret the switch. Monthly hot water costs dropped from $25 to $12. The unit runs quietly enough in the basement that I forget it's there most days. The IRA tax credit made the purchase essentially break even after three years of savings.

But I would not call it a significant upgrade the way switching from a gas furnace to a heat pump for space heating can be. The dollar savings are moderate. The recovery time is noticeably slower. The noise rules out certain installation locations. And the room cooling effect means your real-world savings are slightly less than the headline number.

If your existing water heater is reaching end of life and you can install the new unit in a basement or garage where the noise and cooling don't matter, and you can claim the federal rebate or tax credit, it is a solid investment. If your current heater is working fine and you'd be paying full price out of pocket, the payback period makes it a harder case. The technology is good. The economics depend heavily on the rebate.