Water heaters
Rheem Marathon MR50245C Electric Water Heater, 50 gal
Prices are the equipment only — the appliance, before install labour. Every product in this catalogue currently has at least one real, seller-observed equipment price (see the SKU verification and price observation notes on each product). Get contractor quotes for the install itself, especially for anything needing new electrical circuits or condensate drainage.
Conventional resistance-element electric tank with a lifetime-warranted, non-metallic fiberglass tank — no compressor, no heat pump efficiency, but a tank that structurally can't rust through.
Our take
This is the case for NOT buying a heat pump water heater: a household with cheap electricity, no room for the HPWH's air-space and noise requirements, or simply wanting the lowest-maintenance option money can buy. The tank is genuinely lifetime-warranted because it's wound fiberglass rather than glass-lined steel, so the failure mode that ends most conventional tanks — corrosion through the shell — doesn't apply here. The tradeoff is UEF 0.91: roughly a quarter the efficiency of the heat pump units in this catalogue, because it's pure resistance heat.
Best for
Households prioritising a tank that will outlast the house's other appliances over the running-cost savings a heat pump would deliver.
Watch out for
Straight resistance heat is the most expensive way to make hot water per kWh. Compare your actual electric rate against a heat pump unit's operating cost before assuming 'lifetime warranty' is the better deal.
What sellers are actually charging
Real listings, read on the date shown. Prices change — click through to check before you act on any of them.
| Seller | What you get | Price | Seen |
|---|---|---|---|
| SupplyHouse.com
online retailer |
Rheem Marathon MR50245C, 50gal
MR50245C |
$1,943 | 2026-08-16 |
Equipment price is not installed price. The listings above are what the hardware costs. Installation — labour, electrical, refrigerant lines, permits, removing the old system — is typically a similar amount again, and varies more between contractors than between brands. Where we have an installed figure it is labelled as such and comes from someone who actually installs.
What owners and installers report
Collected from trade forums, owner communities and video reviews. Every report links to the original. We synthesise and quote briefly — we don't republish other people's writing.
Every report below traces back to a single source. The sections are broken out by topic because that's how they read, but treat this as one data point, not independent corroboration across topics — a second source agreeing (or disagreeing) would change that.
Reliability and failures
What breaks, when, and how often — from people several years in.
Company-blog roster of reported Marathon failure modes (leaks within days, heating-element failures, vacuum relief valve defects, thermostat inconsistency, mineral-buildup noise). No named reviewers, dates or links to underlying complaints — read as a hypothesis of what to look for, not a verified claim. Two more promising venues (Bogleheads, TractorByNet) were checked and returned either a paywall or no citable claim either way.
How Did A 'Lifetime' Water Heater Fail? Rheem Marathon Water Heater Problems · Independent trade-company blogs · 2025-06-18 · read it in context
Sources are linked so you can verify any of this yourself. We don't mirror content — Amazon in particular permits no republication of review text, so where we use retailer data we show the aggregate rating and link out. How we collect and weight this →
Compare against
Rheem ProTerra Hybrid Heat Pump Water Heater, 50 gal
The default heat pump water heater for most US households: 50 gallons, UEF 3.75, widely stocked and widely serviced.
Rheem ProTerra Hybrid Heat Pump Water Heater, 80 gal
80-gallon version of the ProTerra, UEF 4.0 — the highest efficiency in the mainstream heat pump water heater market.
A. O. Smith ProLine XE Voltex AL (HPTS-66) Heat Pump Water Heater, 66 gal
66-gallon heat pump water heater with a UEF of 4.02, the highest figure in our water heater set. Sold under A. O. Smith's 'ProLine XE Voltex AL / Smart Hybrid' line — a different, retail-exclusive 'Signature Series' name is used for a different model-number family at Lowe's, so don't cross-shop the names.
A. O. Smith ProLine XE Voltex AL (HPTS-80) Heat Pump Water Heater, 80 gal
80-gallon version of the same ProLine XE Voltex AL 'Smart Hybrid' platform as the HPTS-66 — same compressor and control architecture, larger tank.
Before you buy this
Ask for the first-hour rating, not just tank size, and check it against your household's simultaneous demand — showers and laundry at the same time — rather than headcount alone. If it's a heat pump water heater, confirm the room has enough air volume (or a duct kit) that it won't spend winter on resistance backup, and that there's a real route for condensate, not just a nearby floor drain. Confirm the panel has spare 240V capacity. And if you're removing a gas unit that shared a flue with a furnace, ask what happens to that flue once your water heater's draft is gone — an orphaned flue can backdraft.