Two federal rules govern what water heater you’ll be able to buy, Congress killed one of them and left the other standing, and the tax credit that used to pay for the expensive option expired at the end of 2025. If you’re replacing a water heater in 2026, those three facts matter more than any product feature.
Here’s what actually changed, followed by what to buy.
Our Top Water Heaters
The 2029 Rule: Electric Tanks Become Heat Pumps
The Department of Energy’s 2024 efficiency standard for consumer water heaters takes effect on May 6, 2029. For electric storage water heaters between 20 and 55 gallons it requires a UEF of 2.30; from 55 to 120 gallons, 2.50.
Those numbers are the whole story, because an electric resistance element physically cannot exceed a UEF of about 0.95. You can’t get to 2.30 by heating water with a coil — only a heat pump, which moves heat instead of making it, reaches efficiencies above 1. So from May 2029, essentially every new electric storage water heater in that size range has to be a heat pump model.
Gas storage heaters got a modest efficiency bump in the same rule, with no fuel switching required.
As of this writing, that rule is intact — no delay, withdrawal or rescission appears in the Federal Register or the DOE’s regulatory agenda.
The Tankless Rule Congress Killed
A separate DOE rule published in December 2024 would have effectively required condensing technology for gas tankless water heaters. Congress overturned it under the Congressional Review Act — Public Law 119-6, signed May 9, 2025 — and the DOE formally withdrew the rule that same month.
The practical consequence: non-condensing gas tankless heaters remain on the market. Rinnai still sells its RE series at UEF 0.81. For comparison, ENERGY STAR requires 0.95 or better for a whole-home gas tankless, which in practice means condensing.
The 25C Tax Credit Is Gone
This one costs real money and a lot of pages still get it wrong. The Energy Efficient Home Improvement Credit (Section 25C) paid 30% of project cost up to $2,000 for a heat pump water heater. Legislation enacted July 4, 2025 moved its expiration from 2032 to December 31, 2025. Equipment placed in service after that date does not qualify.
Worth correcting a persistent myth while we’re here: 25C never had income limits. No income test appears anywhere in the statute. (Note also that the IRS’s own “Home energy tax credits” landing page still displays the old table without the expiration — don’t rely on it.)
What replaced it: the IRA Home Energy Rebates, which fund up to $1,750 toward a heat pump water heater for qualifying households. These are administered state by state and availability varies considerably. Check your state energy office before assuming anything.
One Honest Note About Buying These Online
Most water heaters are not Amazon purchases. Rheem’s ProTerra, A.O. Smith’s Voltex and everything Bradford White makes are not sold on Amazon — searches return replacement parts and unfamiliar off-brands. Bradford White sells exclusively through wholesale distribution as a matter of company policy. What genuinely does sell online: point-of-use units, tankless heaters and some Rheem tanks.
Installed costs, per one industry estimate: gas tank $700–2,700, electric tank $600–3,500, tankless $1,400–3,900, heat pump $1,200–3,500 — with labor running about half the total.
The Best Water Heaters in 2026
1. Rheem ProTerra — Best Heat Pump
The heat pump water heater to know about, and the one that makes the 2029 rule look less like a burden. The 80-gallon model posts a UEF of 4.07 with a first-hour rating of 87 gallons — meaning it delivers roughly four units of heat for every unit of electricity, against 0.95 for a resistance tank. Running costs fall by roughly three quarters.
It runs at 45 decibels, which matters because heat pump water heaters have a fan and a compressor; older ones were genuinely annoying in a finished basement. Wi-Fi connected, ducting-ready, ten-year warranty on tank and parts.
The variant worth knowing about is the 120-volt plug-in version (UEF 3.46): it runs off a standard outlet, so a household replacing a gas heater doesn’t need a 240-volt circuit run and a panel upgrade. That single feature removes the biggest practical obstacle to switching.
One correction from our research: Rheem’s own site lists a first-hour rating of 87 gallons for the 50-gallon model, but the ENERGY STAR certified-products database — the government’s own dataset — puts it at 67. Use 67 when sizing.
Specifications:
- UEF: 4.07 (80 gal) / 3.88 (50 gal)
- First-hour rating: 87 gal (80) / 67 gal (50)
- Noise: 45 dBA
- Warranty: 10 years tank and parts
PROS:
- Roughly a quarter of the running cost of a resistance tank
- 120V version avoids an electrical upgrade
- Quiet for a heat pump
CONS:
- Not sold on Amazon — go through a plumber or big-box supplier
- Needs air volume around it; not for a tight closet
Conclusion
If you’re replacing an electric tank and have the space, this is the buy — and after May 2029 it’s essentially the only category available anyway.
2. A.O. Smith Voltex MAX — Heat Pump Runner-Up
UEF 3.68 on the 50-gallon, rising to 3.88 on the 80 — with a 65-gallon first-hour rating, 45 decibels and a ten-year warranty. Every one of those figures is confirmed in the government’s ENERGY STAR database as well as A.O. Smith’s own documentation, which is more than we could say for several competitors.
A.O. Smith’s line has three tiers and the names blur: Voltex MAX sits above ProLine XE Voltex AL, which sits above plain ProLine XE Voltex. A 2017-era recommendation for “the A.O. Smith Voltex” now points at the oldest and least efficient of the three.
Specifications:
- UEF: 3.68 (50 gal), 3.88 (80 gal)
- First-hour rating: 65 gal
- Noise: 45 dBA
PROS:
- Best-documented specifications in the category
- Ten-year warranty
CONS:
- Confusing three-tier naming
- Not on Amazon
Conclusion
A straightforward alternative to the ProTerra. Worth naming a third option too: Bradford White’s AeroTherm Series G2 posts the highest efficiency we found anywhere — UEF 4.20 on the 65-gallon — but the company sells only through wholesalers, so you’ll get it through a plumber or not at all.
3. Rheem PROG50-40N — Best Gas Tank
The unglamorous answer that fits most American houses: a 50-gallon atmospheric-vent gas tank, 40,000 BTU, around $1,145 and genuinely available online. Gas storage heaters lost market share for the first time in years — electric storage crossed 50% of shipments in 2024 — but they remain the cheapest same-day replacement for a house already plumbed for gas.
If you want the better-documented option and don’t mind ordering through a supply house, A.O. Smith’s ProLine Master HUR-50 posts UEF 0.64 with an 84-gallon first-hour rating and an eight-year warranty.
Specifications:
- Capacity: 50 gallons, 40,000 BTU
- Venting: atmospheric
PROS:
- Cheapest fast replacement for a gas home
- Actually purchasable online
CONS:
- Efficiency around 0.64 UEF — a heat pump is six times better per unit of energy
Conclusion
The pragmatic choice when the old one has already flooded the basement and you need hot water tonight.
4. Rinnai SENSEI RX Series — Best Tankless
Rinnai’s current condensing line replaced the RU, RUR and RUC models a 2017 guide would have recommended — if you’re cross-shopping old reviews, those model numbers are dead. The flagship RX199iN delivers 11.1 gallons per minute at UEF 0.98, converts between natural gas and propane with an adaptive valve, and vents indoors or out.
The one to actually buy online is the RX160iN at about $1,443 for 9 GPM — enough for two simultaneous showers in most climates. Note the pricing quirk: the legacy RU199iN still sits on Amazon at over $2,100, well above the newer, better RX160iN.
Sizing is the thing people get wrong. Tankless capacity depends on how much you’re raising the incoming water temperature — a unit rated 9 GPM in Florida delivers considerably less in Minnesota in January. Size for your coldest month, not the brochure number.
Specifications:
- Flow: 11.1 GPM (RX199iN) / 9 GPM (RX160iN)
- UEF: 0.98 — condensing
- Indoor or outdoor installation
PROS:
- Endless hot water, no standby losses
- Compact — frees up floor space
CONS:
- Output drops in cold climates
- Gas line and venting upgrades often required
Conclusion
Excellent where hot water demand is spiky and space is tight. Since Congress overturned the condensing rule, cheaper non-condensing units (around UEF 0.81) also remain available — they’re less efficient but simpler to vent.
5. EcoSmart ECO 11 — Best Point-of-Use
For a garage sink, a workshop, a guest bath at the far end of the house, or a wet bar — anywhere you want hot water without waiting for it to travel from the basement. About $249, 13 kW, digital temperature control in one-degree steps from 80 to 140 °F, and a limited lifetime warranty.
Read the electrical requirements before you buy: this needs a 60-amp double-pole breaker and 6-gauge wire. That’s a real circuit, not a spare outlet, and it’s the reason point-of-use heaters get returned. UEF is 0.92 — the product page’s “up to 0.96” figure belongs to the smaller ECO 8.
Specifications:
- Power: 13 kW at 240V; 60A double-pole breaker
- Temperature: 80–140 °F in 1° increments
- Size: 11.4 × 7.9 × 3.7 in, 6.5 lb
PROS:
- Instant hot water at a remote fixture
- Tiny, wall-mounted
CONS:
- Serious electrical requirements
- Whole-house use needs the much larger Stiebel Eltron Tempra class
Conclusion
The right fix for one distant fixture. For whole-house electric tankless, the Stiebel Eltron Tempra 24 Plus (UEF 0.97) is the serious option — and it needs two 50-amp breakers and a 150-amp panel.
What Happened to the Old Names
If you’re comparing against an older guide: Rheem’s “Performance Platinum Hybrid” became the ProTerra. GE’s GeoSpring is discontinued — Bradford White took over warranty support for units built before 2017 — though GE has since returned with new Profile heat pump models. Rinnai’s RU/RUR/RUC line became RX and RXP. EcoSmart is now owned by Rheem. And Navien, which made only tankless heaters in 2017, launched a heat pump line in 2025.
Water Heater FAQ
What does UEF actually mean?
Uniform Energy Factor: units of heat delivered per unit of energy consumed. Below 1.0 means some energy is lost — a gas tank at 0.64 wastes about a third. Above 1.0 is only possible for heat pumps, which move existing heat rather than generating it, which is how a UEF of 4.07 is physically possible.
How do I size one?
First-hour rating, not tank size, is the number that matters — it’s how much hot water the heater can actually deliver in an hour of heavy use. A family of four typically wants 60 to 80 gallons FHR. Tank size alone can mislead: a fast-recovery 50-gallon heater can outperform a slow 65.
Is a heat pump water heater cold in the room?
Yes, slightly — it extracts heat from surrounding air, so it cools and dehumidifies the space it’s in. That’s a bonus in a humid basement and a drawback in a heated closet. Most need about 700 cubic feet of air or ducting.
Tankless: worth it?
For endless hot water and space savings, yes. For pure operating cost, a heat pump beats gas tankless comfortably. And factor the install: tankless frequently requires a larger gas line and new venting, which is where budgets break.
How long do these last?
Tanks typically 8 to 12 years; tankless 20 or more. Annual flushing extends both, and in hard water it’s not optional. Rheem’s Marathon line uses a seamless polymer tank that can’t rust and carries a lifetime residential tank warranty — worth a look if you’re staying put.
Summary
Replacing an electric tank: buy the Rheem ProTerra or A.O. Smith Voltex MAX heat pump. It costs more up front, runs at roughly a quarter of the energy, and after May 2029 it’s the only kind of electric tank being made. Gas house needing a fast swap: the Rheem PROG50 does the job for around $1,145. Space-constrained or demand-spiky: Rinnai’s RX series. One far-away sink: the EcoSmart ECO 11 and a proper 60-amp circuit.
And on the money: the federal 25C credit is finished as of the end of 2025, so price your project without it and treat any state rebate you find as a bonus.
