Marathon Energy Star Certified Water Heaters
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No Marathon energy star water heaters in our catalog
Marathon doesn't currently ship any energy star certified water heaters we track. Try one of the alternatives below.
Marathon Energy Star Certified Water Heaters: buyer's guide
Marathon doesn't currently ship any energy star certified water heaters in the lineup we track. If you're shopping for energy star certified water heaters, see the full Energy Star category for cross-brand options.
About Marathon
Marathon (Rheem) — subsidiary of Rheem. Specialty water-heater manufacturer serving the US market.
For the complete Marathon lineup across all sub-types and capacities, see the Marathon Water Heaters hub.
Other Energy Star water heaters brands
If you're cross-shopping energy star water heaters beyond Marathon, the following brands also ship in this category:
About Energy Star Certified Water Heaters water heaters
Energy Star certified water heaters meet US EPA / DOE efficiency standards that qualify them for federal rebates, utility efficiency incentives, and state electrification programs. For 2026, Energy Star certification is the gateway to most rebates and tax credits — including the federal IRA 25C $2,000 heat pump credit, state utility rebates, and many local efficiency incentives.
Energy Star certifies water heaters by UEF (Uniform Energy Factor) thresholds that vary by fuel and capacity:
- Gas tank: UEF ≥ 0.64 (atmospheric) or ≥ 0.81 (condensing)
- Electric tank: UEF ≥ 0.93 (resistance, large-tank) or ≥ 2.0 (heat pump — easily exceeded by modern units at 3.45+ UEF)
- Gas tankless: UEF ≥ 0.93 cond...
For the complete energy star buyer's guide (all brands, full comparison framework), see the Energy Star Certified Water Heaters category hub.
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