U. S. Department of Energy
Final Rule Notification

May 22, 2024
DOE Publishes Final Rule for Residential Water Heater Standards

On May 6, 2024, the U.S. Department of Energy (DOE) published a Final Rule updating the energy conservation standards for residential water heaters. The standards will require minor updates to gas-fired storage water heaters. Electric storage water heaters >35 gallons will require heat pump technology. The gas instantaneous product category has been excluded from this rule and will be addressed by the DOE in a subsequent rulemaking.

The new energy efficiency levels will be required for all residential water heaters produced on and after May 6, 2029.

Below is a summary of the impacts of the final rule:
Gas-fired Storage
• <20 gallon: new standard to add UEF to these models – no current A. O. Smith products impacted
• ≥20 and ≤55 gallon: incremental UEF increase – atmospheric gas units will require the addition of a damper
• >55 and ≤100 gallon: no change
• >100 gallon: new standard to add UEF to these models

Gas-fired Instantaneous
• No change at this time

Electric Storage
• <20 gallon: new standard to add UEF to these models – compact units <20 gallon will have a UEF and FHR value added by the implementation date
• ≥20 and ≤35 gallon: no UEF change but will be limited to a max FHR of 50 gallons and a max temperature setting of 135°F o All nominal 40 gallon electrics are currently rated at 36 or 37 gallons and will have to be reduced to 35 gallons
• >35 and ≤120 gallon: requires Heat Pump Water Heater
• >75 gallon grid-enabled: no change
• >120 gallon: new standard to add UEF to these models – no current A. O. Smith products impacted

Electric Instantaneous
• <2 gallon: no change
• ≥2 gallon: new standard to add UEF to these models – no current A. O. Smith products impacted

We value your partnership, and we are committed to having the products, education and support you will need to be ready for these changes.