Marathon Lifetime 105-Gallon Electric Water Heater
Marathon Lifetime 105-Gallon Electric Water Heater Review
The Marathon Lifetime 105-Gallon Electric is the largest residential Marathon, sized for very large households or commercial-residential crossover applications. Polybuthylene tank, lifetime warranty.
Specs: 105 gallons stored, two 4500W heating elements (240V), UEF 0.92, 120-gallon first-hour rating, lifetime tank warranty + 6-year parts warranty. Polybuthylene fiberglass-reinforced plastic tank. About 60" tall × 32" diameter — substantially larger floor footprint than typical residential 50-gallon units.
The 105-gallon capacity exceeds typical residential demand even for large families. Use cases: very large households (6+ people), homes with multiple-bath overlapping demand, small commercial applications (small restaurant, multi-family residential with shared system).
The Marathon's lifetime polybuthylene tank construction is particularly valuable at this capacity — replacement of a 105-gallon tank is a significant project. Avoiding replacement entirely through the no-rust tank makes the high upfront cost meaningful over 30+ year horizons.
About $3,500 unit, $4,500 installed. Right buyer: 6+ person household, multi-generational home, or small commercial-residential crossover application. Wrong buyer: typical residential households (massively oversized), households with realistic demand profiles served by 50-80 gallon units.
- No combustion, no venting required — installs anywhere with 240V electrical access
- UEF 0.89 electric — well-insulated design minimizes standby loss compared to standard models
- Lifetime tank warranty — industry's strongest coverage; no replacement budget needed
- Large 105-gallon reserve — comfortably serves 5+ person households in peak-use periods
- 125-gallon first-hour rating — handles morning-rush simultaneous demand without shortfall
- Resistance electric has slower recovery than gas at comparable capacity — schedule heavy use to match tank recovery