Water heaters
Rheem Performance RETEX-24 Self-Modulating Electric Tankless Water Heater
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.
Rheem's self-modulating electric tankless: 24kW, UEF 0.93, roughly 4.68 GPM at a 35°F-equivalent rise, a 5-year heat-exchanger warranty and 1-year parts.
Our take
Rheem sells two different 24kW electric tankless lines that look almost identical in a search result: the retail 'Performance RETEX-24' (this one, sold at Home Depot) and the wholesale 'Professional Classic RTEX-24' -- no E -- which carries different UEF and warranty terms. Make sure whatever price you're comparing is actually for this unit. Against the Stiebel Eltron Tempra 24 Plus a shelf over, the two are close on paper -- same 24kW, same 0.93 UEF, both land around 4.68 GPM at a 35°F rise -- but RETEX-24's warranty is thin: 1 year on parts against Tempra's 3 years parts and 7 years limited. If a comparable retail-channel electric tankless is what you want and warranty length doesn't matter, this is the cheaper way in. If it does, look at the Tempra.
Best for
Retail-channel buyers wanting a self-modulating 24kW electric tankless without paying the Stiebel Eltron premium.
Watch out for
Don't confuse this with the wholesale 'RTEX-24' (no E) -- different product, different numbers. And the 1-year parts warranty is short next to the Tempra 24 Plus's 3-year term; factor that into the price comparison, not just the sticker price.
What sellers are actually charging
The lowest in-stock, full-equipment price we've seen is $549, at Home Depot, seen 2026-08-30. Every listing from the last 30 days, newest first, is below — prices change, click through to check before you act on any of them.
| Seller | What you get | Price | Stock | Seen |
|---|---|---|---|---|
| Home Depot
big box retailer |
equipment system | $549 | in stock | 2026-08-30 |
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.
Owner of the sibling RETEX-18 (same self-modulating electric-tankless platform as the cataloged RETEX-24, different kW rating) reports the unit stopped heating entirely after a routine descale/deliming, pushing only cold water through; resolution not confirmed in-thread.
“We just delimed our Rheem RETEX-18 tankless water heater. After hooking it back up, it doesn't heat water at all, just pushes cold water through.” — N08LE homeowner, 2025-03-17
Reported on the Performance RETEX line; size not stated — included here because it's the same family and counts toward the totals above.
Rheem tankless water heater not heating after deliming · Terry Love Plumbing Forum · 2025-03-17 · 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
Stiebel Eltron Tempra 24 Plus Electric Tankless Water Heater
Stiebel Eltron's Advanced Flow Control electric tankless: 24kW, UEF 0.93, roughly 4.68 GPM at a 35°F-equivalent rise, a 3-year parts warranty (7-year limited).
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.
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.