Water Heater Energy Efficiency Ratings
Updated February 20, 2026
Key Takeaway
Water heating is 14-18% of utility bills. UEF (Uniform Energy Factor) tells you efficiency -- higher is better. Heat pump water heaters are 2-3x more efficient than standard electric. Gas condensing models are 30-50% more efficient than standard gas.
Overview
Water heating is 14-18% of utility bills. UEF (Uniform Energy Factor) tells you efficiency -- higher is better. Heat pump water heaters are 2-3x more efficient than standard electric. Gas condensing models are 30-50% more efficient than standard gas.
What to Know
Buying Tips
- Heat pump offers lowest operating cost of any electric option.
- Compare annual operating cost on EnergyGuide label, not just purchase price.
- Federal tax credits can reduce heat pump cost to near-standard electric prices.
- If switching gas to heat pump, calculate net savings including gas line elimination.
Common Mistakes
- Buying cheapest heater without considering operating cost.
- Comparing UEF across fuel types -- electric UEF is naturally higher but electricity costs more per BTU usually.
- Ignoring tax credits and rebates.
- Assuming gas is always cheaper than electric.
Bottom Line
Higher UEF means lower bills. Heat pump electric is most efficient. Check tax credits before buying. Compare total cost of ownership over 10 years, not just sticker price.