Rheem · Updated July 2026

Rheem RTEX-18: price & specs

Name: Rheem RTEX-18
Brand: Rheem
Price: 523.99 USD
Availability: InStock

The Rheem RTEX-18 costs $523.99, the cheapest tankless water heaters (median $1295.62). It earns a Bronze Deskmark — 0/100 pay-blind standing, #8 of 8 in class.

Verified Jul 11, 2026 · figures linked to their source in the table below

See Rheem RTEX-18 on Amazon Recorded 2026-07-11 — live price may differ. As an Amazon Associate we earn from qualifying purchases.

Rheem RTEX-18. Every price and spec below is linked to its source and dated — no guesses.

Source: rheem.com verified 2026-07-11 ✓ corroborated verify in ledger

Rheem RTEX-18 — Rheem — Image: factorypure.com (© Rheem)

Is the Rheem RTEX-18 a good buy?

At $524, the Rheem RTEX-18 is the cheapest of the 7 tankless water heaters we track, where the median is $1295.62. On the spec sheet, its max flow rate gpm of 4.4 is the lowest of the 8, its min activation flow gpm of 0.3 is the lowest of the 7, and its heat exchanger warranty yrs of 5 is the lowest of the 7.

Specifications

Price (US)	$523.99 US retail price $523.99 listed verbatim on FactoryPure product page (SKU RTEX-18, "$ 523.99", data-price-raw="52399"), accessed 2026-07-11. Rheem.com publishes no MSRP for this model.
Brand	Rheem
Released	—
Fuel type	electric
Max flow rate gpm	4.4
Max btu per hour	—
Power input (kW)	18
Uniform energy factor	0.94
Condensing type	electric
Min activation flow gpm	0.3
Vent type	none
Max temp f	140
Heat exchanger warranty yrs	5
Wi-Fi enabled	No
Weight (lb)	—

Source: rheem.com (verified 2026-07-11) · corroborated by factorypure.com. The official Rheem product page confirmed model identity ("MODEL RTEX-18", "SKU RTEX-18", Professional Classic Series Tankless Electric RTEX-18) and verbatim specs: electric with no venting required (ventType none/condensing electric), digital control 80-140°F, "UEF up to .94", "Heating Chamber - 5 Years", and a "MAX FLOW (GPM) RTEX-18 4.4" figure. The FactoryPure retailer page corroborated the same model (SKU RTEX-18, Model Number RTEX-18) with a structured spec table giving Power (kW) 18, UEF 0.94, Flow Activation Rate 0.3 GPM, and up to 4.4 GPM flow, plus the listed US retail price of $523.99. Weight was left null because only a ship weight (14.78 lbs), not dry unit weight, was published, and the heat-exchanger warranty follows the manufacturer's authoritative 5-year figure over FactoryPure's inconsistent copy-paste text.

Is the Rheem RTEX-18 worth it vs cheaper tankless water heaters?

Rheem RTEX-18 against its closest cheaper and pricier tankless water heaters on the specs that matter — every value sourced. See all 7 ranked →

Product	Price	Fuel type	Max flow rate gpm	Power input (kW)	Uniform energy factor	Condensing type
Rheem RTEX-18 this	$523.99	electric	4.4	18	0.94	electric
EcoSmart ECO 24	$525	electric	—	24	—	electric

Frequently asked questions

How much does the Rheem RTEX-18 cost?

The Rheem RTEX-18 has a US price of $523.99 (US retail price $523.99 listed verbatim on FactoryPure product page (SKU RTEX-18, "$ 523.99", data-price-raw="52399"), accessed 2026-07-11. Rheem.com publishes no MSRP for this model.), as of 2026-07-11.

How does the Rheem RTEX-18 compare on price?

At $524, the Rheem RTEX-18 is the cheapest of the 7 tankless water heaters we track, where the median is $1295.62.

What are the Rheem RTEX-18's key specs?

Rheem RTEX-18 (Rheem): fuelType electric, maxFlowRateGpm 4.4, powerInputKw 18, uniformEnergyFactor 0.94, condensingType electric. Full sourced spec sheet verified 2026-07-11.