This is the most direct comparison in the residential water heater market — two brands that eliminate the corrosion failure mode and offer lifetime tank warranties. Different materials (stainless steel vs composite polybutylene), different product breadth, different pricing.
Side-by-side (50-gallon electric)
| Westinghouse WER050 | Marathon MR50 | |
|---|---|---|
| Tank material | 316L stainless steel | Polybutylene liner + fiberglass shell |
| Tank warranty | Lifetime (residential) | Lifetime (residential) |
| Anode rod | None | None |
| Affected by water chemistry | Resistant to most chemistries; limits in extreme chlorides | Inert to all common water chemistries |
| Tank lifespan reports | 15-25+ years (newer in market) | 20-30+ years (established since 1989) |
| Weight | Standard stainless weight | Lighter (composite) |
| Typical price | $1,049-1,299 | $1,299-1,599 |
Product range
| Product category | Westinghouse | Marathon |
|---|---|---|
| Electric storage tank | WER 40/50/80-gal | MR 40/50/55/66/75/85/105-gal + MHD Heavy Duty + MRH Lowboy |
| Gas storage tank | WGR 40/50/75/80 atmospheric + WGRPV Power Vent | None (electric-only) |
| Gas tankless | WGRGH 7.5/9.6/11 GPM | None |
| Electric tankless | WET 18/27/36 kW | None |
| Heat pump | WH 50/80-gal hybrid | None |
Where Westinghouse wins
- Wider product range — gas tank, gas tankless, electric tankless, heat pump all available; Marathon is electric-only
- Lifetime gas tank — Marathon doesn\'t make gas; Westinghouse offers stainless gas with lifetime warranty
- Lower pricing on electric tanks — typically $200-300 less than equivalent Marathon
- Stainless heat pump — combines lifetime tank with heat pump efficiency in one product
- Multi-product brand-loyalty option — can do storage + tankless + heat pump in one ecosystem
Where Marathon wins
- Longer track record — composite tank in market since 1989; 35+ years of field data
- Broader residential electric tank sizing — Marathon has 7 sizes (40/50/55/66/75/85/105-gal) vs Westinghouse 3 (40/50/80)
- Heavy Duty option (MHD) — 5500W elements for faster recovery
- Lowboy option (MRH) — mobile home and low-ceiling applications
- Lighter tank weight — easier handling during install
- Rheem corporate parent — established US support network
The material decision
Stainless 316L advantages
- Metal pressure tolerance
- Higher temperature limits
- Available in gas (Marathon composite isn\'t)
- Familiar maintenance (standard parts compatibility)
Composite polybutylene advantages
- Truly inert to water chemistry — no pitting from extreme chlorides
- Lighter handling
- Longest track record of lifetime warranty in market
Which to choose
- Electric tank only, longest residential track record: Marathon
- Electric tank, budget-conscious, lifetime warranty: Westinghouse WER050
- Gas tank with lifetime warranty: Westinghouse WGR — Marathon doesn\'t compete
- Tankless preferred: Westinghouse WGRGH or WET — Marathon doesn\'t compete
- Heat pump with lifetime tank: Westinghouse WH HP — Marathon doesn\'t compete
- Heavy Duty fast recovery electric: Marathon MHD — Westinghouse doesn\'t compete
- Mobile home lowboy install: Marathon MRH — Westinghouse doesn\'t offer
Bottom line
For electric storage tank only, both work — Marathon has the longer track record, Westinghouse has the lower price. For anything beyond electric storage (gas tank, tankless, heat pump), Westinghouse is the obvious choice because Marathon doesn\'t make those products. The brands are complementary rather than competitive for many buyers.