Water heaters

Rheem Marathon MR50245C Electric Water Heater, 50 gal

Rheem MR50245CPro Partner and big-box retail 50% data complete
$1,943 – $1,943
equipment only · 1 seller · seen 2026-08-16

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.

See the 1 listing this comes from →

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 — none currently in stock at the observed price. Prices change — click through to check before you act on any of them.

SellerWhat you getPriceStockSeen
SupplyHouse.com
online retailer
equipment system $1,943 out of stock 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.

Reliability and failures

What breaks, when, and how often — from people several years in.

mixed
3 reports
38% evidence

Thin evidence — too few independent reports to call this a pattern. Shown because it may still be worth asking your contractor about.

A plumbing-forum commenter, in a thread about whether to buy a Rheem Marathon lifetime-warranty tank, said their own experience with plastic-tank water heaters has been that the fitting connections where they enter the tank tend to fail over time -- a design-level durability concern about the tank material/construction rather than a specific single unit. A general remark about the Marathon poly-tank line, not confirmed against the 50-gallon MR50245C specifically. No post date is available on this forum's page.

“I have not had good luck with heaters which had a plastic tank. The connections often fail where they connect into the tank.” — hj

Pros thoughts on Rheem Marathon tank · Owner/trade forums (misc.) · read it in context

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

An owner reports their 18-year-old Marathon water heater has never given them any trouble under a lifetime tank warranty.

“This heater has a lifetime warranty on the tank and has never given me any trouble.” — not-a-plumber, 2019-01-05T16:20:59-0500

Reported on the Marathon line; size not stated — included here because it's the same family and counts toward the totals above.

https://www.plumbingforums.com/threads/heat-pump-water-heater-or.14203/ · PlumbingForums.com · 2019-01-05T16:20:59-0500 · read it in context

Warranty and manufacturer support

What actually happens when owners make a claim.

neutral
1 report · 1 from trade
19% evidence

Thin evidence — too few independent reports to call this a pattern. Shown because it may still be worth asking your contractor about.

A trade professional notes Rheem Marathon tanks are composite construction with a lifetime warranty, and describes Rheem's 4-year warranty extension kit as adding a second anode rod.

“Rheem Marathon is composite and lifetime warranty. Rheem 4 year warranty extension kit adds a second anode rod.” — GReynolds929 trade, 2024-04-27T13:58:54-0400

Reported on the Marathon line; size not stated — included here because it's the same family and counts toward the totals above.

https://www.plumbingforums.com/threads/heat-pump-water-heater-location.25956/ · PlumbingForums.com · 2024-04-27T13:58:54-0400 · 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

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.