Water heaters
Stiebel Eltron Tempra 24 Plus 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.
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).
Our take
This is the trade answer to the big-box RETEX-24 sitting one slot over: same 24kW output, the same 0.93 UEF, and functionally the same ~4.68 GPM at a 35°F rise, but Stiebel Eltron backs it for 3 years on parts and 7 years limited against RETEX-24's 1 year on parts. That extra coverage -- and a longer trade reputation on the flow-control electronics electric tankless buyers actually complain about -- is what the premium buys, not more hot water. If the two units perform this close on the spec sheet, the warranty term is doing most of the argument for paying more.
Best for
Buyers wanting a self-modulating 24kW electric tankless with real warranty backing, working with a plumber who already stocks Stiebel Eltron.
Watch out for
The UEF figure here came from a spread of sources (0.92-0.97 depending on the listing) rather than one clean number off Stiebel Eltron's own per-model spec sheet -- the 0.93 used here has two independent citations, but if your installer quotes a different figure, ask which document it's from.
What sellers are actually charging
The lowest in-stock, full-equipment price we've seen is $649, 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 | $649 | 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.
Controls and compatibility
Thermostat integration, communicating-system lock-in, firmware, and whether the equipment achieves its rated staging in practice. On tankless water heaters this also covers ignition delay and the 'cold water sandwich' effect.
Owner reports the Tempra 24 Plus's shower temperature swings about 7 degrees and water pressure fluctuates strongly during normal multi-fixture use, three months after install, with no thermostatic mixing valve fitted; the issue worsened as incoming water got colder in fall.
“the water temperature fluctuates at the shower (+/- 7 degrees) and the water pressure also fluctuates very strongly” — fullfins homeowner, 2010-10-13
Tankless woes · Terry Love Plumbing Forum · 2010-10-13 · 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 Performance RETEX-24 Self-Modulating Electric Tankless Water Heater
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.
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.