What this means for you
I have an electric tank water heater
Major change aheadIf your tank is over 35 gallons, new units after May 2029 must use heat pump technology. Your existing unit is grandfathered, but your next replacement will likely be a heat pump. Browse models →
I have a gas tank water heater
Modest changeGas storage water heaters will still be available after 2029 with minor design changes (flue damper). No technology shift to condensing required. Browse models →
Estimated savings
Over 50% of newly manufactured electric storage water heaters will use heat pump technology (up from ~3% today)
Product classes affected
| Class | Status | Summary |
|---|---|---|
| Electric Storage | ACTIVE - major changes | Electric storage water heaters >35 gallons will require heat pump technology. This is the most impactful change in the rule. |
| Gas Fired Storage | ACTIVE - moderate changes | Incremental UEF increase for gas storage 20-55 gallons. Atmospheric gas units will require the addition of a flue damper. No technology shift to condensing required. |
| Oil Fired Storage | ACTIVE - addressed in rule | Moderate efficiency increase for oil-fired storage water heaters. |
| Electric Instantaneous | ACTIVE - addressed in rule | New UEF standards of approximately 0.91-0.92 depending on draw pattern. |
| Gas Fired Instantaneous | WITHDRAWN | The separate rule requiring condensing technology (UEF 0.91 medium draw, 0.93 high draw) was withdrawn via Congressional Review Act on May 20, 2025. Current standards remain in effect. No new requirements. |
Electric storage breakdown
| Capacity | Change | Technology | Severity |
|---|---|---|---|
| Under 20 Gallons | New standard adds UEF and First Hour Rating (FHR) requirements for compact units. Previously had no UEF requirement. | Electric resistance permitted | minor |
| 20 To 35 Gallons | No UEF change. New limits: max FHR of 50 gallons, max temperature setting of 135F. All nominal 40-gallon electric storage units must be reduced to 35 gallons rated storage volume. | Electric resistance permitted | moderate |
| > 35 To 55 Gallons | New UEF standards require heat pump technology. Electric resistance water heaters in this size range become non-compliant. | Heat pump | major |
| > 55 To 120 Gallons | New UEF standards require heat pump technology. Required UEF between 1.9 and 2.4 depending on draw pattern and rated storage volume. Electric resistance water heaters in this size range become non-compliant. | Heat pump | major |
This is the biggest change. Standard electric resistance tanks over 35 gallons will no longer be manufactured after May 2029.
What becomes non-compliant
Cannot meet new UEF requirements without heat pump technology. Standard electric resistance tanks >35 gallons (including the most common 40, 50, 55, 65, 80 gallon sizes) will be non-compliant.
Atmospheric gas storage units 20-55 gallons will require a flue damper to meet incremental UEF increase.
The rule requiring condensing technology for gas tankless was WITHDRAWN via Congressional Review Act in May 2025. Non-condensing gas tankless water heaters remain compliant under current standards.
Gas tankless rule (withdrawn)
Withdrawn 2025-05-20 via Congressional Review Act, H.J.Res. 20, signed by President Trump on 2025-05-09.
Under the Congressional Review Act, DOE cannot issue a substantially similar rule without new Congressional authorization.
What to buy today
| Situation | Guidance |
|---|---|
| Electric Resistance Under 35 Gal | Still compliant after 2029. Safe to buy. |
| Electric Resistance 36 To 55 Gal | Will be non-compliant for new manufacture after May 2029. Existing installed units are grandfathered. Replacement parts available. But next replacement will likely need to be a heat pump. |
| Electric Resistance Over 55 Gal | Will be non-compliant for new manufacture after May 2029. Same grandfathering applies. |
| Heat Pump Water Heater | Already exceeds 2029 standards. Future-proof purchase. The federal 25C tax credit expired December 31, 2025; check your state for active rebates. |
| Gas Storage | Modest efficiency increase required. Gas storage water heaters will still be available after 2029 with minor design changes (damper addition). |
| Gas Tankless | No new federal requirements after withdrawal of the December 2024 rule. Current models remain compliant. |
UEF standard examples
| Scenario | Min UEF | Note |
|---|---|---|
| Electric 55 Gal High Draw Current | 0.93 | Current standard, achievable with electric resistance |
| Electric 65 Gal High Draw 2029 | 2.20 | 2029 standard, requires heat pump technology |
| Electric 80 Gal Medium Draw 2029 | 2.10 | 2029 standard, requires heat pump technology |
| Gas 40 Gal High Draw 2029 | 0.64 | 2029 standard, achievable with non-condensing + damper |
UEF standards are formulas based on rated storage volume. Full formulas in 89 FR 37778 Table I.1.
Timeline
Legal status
IN EFFECT. No successful legal challenge as of this date. Court upheld related DOE efficiency rules in November 2025.
WITHDRAWN via Congressional Review Act, May 2025.
As of 2026-03-12. Under the Congressional Review Act, DOE cannot issue a substantially similar rule to the withdrawn gas-fired instantaneous standard without new Congressional authorization.