A reader named Priya emailed me last month asking why the same Rheem tankless heater showed three different prices across three different sites in the same afternoon. That’s actually normal in this category. Tankless electric heaters get bundled, discounted, and repriced constantly depending on the retailer and whether you’re buying the whole-home model or a smaller point-of-use version. Here’s what the RTEX-24 actually costs and where that number comes from.
The Rheem RTEX-24 sells for $549.00 new on Amazon as of 2026, with used units starting around $355.14 and third-party new listings occasionally dipping to $542.99. That’s the price for the 24kW “Whole Home” version specifically. Rheem sells five other RTEX sizes at different price points, so it’s worth confirming you’re comparing the right model before assuming you found a better deal elsewhere.
The Full RTEX Price Lineup (So You Don’t Overpay for the Wrong Size)
Rheem’s tankless electric lineup runs from small point-of-use units to the whole-home 24kW model. Here’s the actual pricing across the family, pulled directly from Rheem’s own product listing:
| Model | Max GPM | Power | Price |
|---|---|---|---|
| RTEX Point-of-Use, 3.5 kW | up to 0.9 | 120V | $244.99 (used) |
| RTEX Point-of-Use, 6.5 kW | up to 1.6 | 240V | $161.40 |
| RTEX Point-of-Use, 8 kW | up to 1.95 | 240V | $256.81 |
| RTEX Point-of-Use, 11 kW | up to 2.68 | 240V | $252.18 |
| RTEX Whole Home, 18 kW | up to 4.4 | 240V | $438.00 |
| RTEX-24 Whole Home, 24 kW | up to 5.9 | 240V | $549.00 |
Notice the smaller units aren’t automatically cheaper per GPM. The 8kW and 11kW point-of-use models actually cost more than the 6.5kW unit despite similar size, because they’re built for higher simultaneous demand at a single point of use (like a kitchen plus a bathroom sink). Price scales with capability, not just size.
What You’re Actually Paying For at $549
The RTEX-24 is the largest unit in the family that (that isn’t the newer 27kW or 36kW updates sold under different Rheem lines), rated for up to 5.9 GPM and enough to run 2 showers and 2 sinks simultaneously in a warm climate, according to Rheem’s own product specifications. It uses 3 heating elements pulling a combined 24kW at 240V, requiring three 40-amp double-pole breakers.
That $549 sticker price does not include installation. Based on real reviews on the product listing, electrician costs for the panel work alone ran one reviewer $850 for a licensed electrician and journeyman working about three hours, including a new auxiliary breaker box. That’s a meaningful number to budget for beyond the unit price itself.
New vs Used: Is the Used Option Worth the Savings?
Amazon lists a “Used - Very Good” RTEX-24 through Amazon Resale for $355.14, which is roughly 35% off the new price. For a $549 appliance, that’s a real discount, but a few things are worth knowing before buying a used tankless water heater:
- You lose the ability to verify how long it operated before resale, or whether the original heating elements have significant mineral scale buildup
- Amazon Resale items still carry Amazon’s standard return window, which reduces some of the risk
- A water heater with worn heating elements may run less efficiently even if it technically still works, meaning your electric bill could offset some of what you saved upfront
If your budget is tight and you’re comfortable with some risk, the used option is not unreasonable given Amazon’s return policy. If this unit is replacing your only source of hot water for your household, the $194 savings is a smaller cushion than it looks once you weigh in the risk of an early failure.
Rebates That Can Lower Your Real Cost
Rheem’s own product page notes that energy provider rebates may be available, and this is worth checking before you buy since it can meaningfully change the math. According to the U.S. Department of Energy, tankless water heaters (point-of-use models specifically) can save up to 50% on water heating costs compared to tank-type heaters, while whole-home models like the RTEX-24 can save up to 34%, based on figures Rheem cites directly from the DOE. Many utility companies offer rebates specifically for switching from a tank to a tankless system, so check with your local energy provider before you buy, some rebate programs require pre-approval before installation, not after.
Is $549 Actually a Good Price?
Compared to similarly rated electric tankless competitors in the same power class, $549 sits in a reasonable middle ground, not the cheapest option on Amazon, but backed by a well-known 100-year-old manufacturer and a large enough sales volume (100+ units bought in the past month per Amazon’s own listing) that parts and support are easy to find. If your only concern is sticker price, there are cheaper off-brand 24kW units on Amazon. If you want a widely supported unit with an established parts ecosystem, the RTEX-24’s price reflects that.
For the full breakdown of what this unit does well and where it falls short, see our complete Rheem RTEX-24 review.
Ready to buy? Here’s the current listing:
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater - View Price on Amazon
The Bottom Line
The Rheem RTEX-24 costs $549 new, with used units available for meaningfully less if you’re comfortable with the tradeoffs. Factor in electrician costs of several hundred dollars if your panel needs upgrading, and check for utility rebates before you finalize your budget. The unit’s price sits fairly in its class once you account for brand support and parts availability.
Frequently Asked Questions
How much does the Rheem RTEX-24 cost? The RTEX-24 costs $549.00 new on Amazon as of 2026, with used units available starting around $355.14.
Does the Rheem RTEX-24 price include installation? No. The $549 price is for the unit only. Installation, particularly electrical panel work, is a separate cost that can run several hundred dollars depending on your home’s existing electrical capacity.
Are there rebates available for the Rheem RTEX-24? Rheem’s product listing notes that energy provider rebates may be available depending on your location and utility company. Check with your local energy provider before purchasing, since some rebates require pre-approval.
Is the used Rheem RTEX-24 on Amazon a good deal? It can be, at roughly 35% off the new price, but you lose visibility into the unit’s prior usage and heating element condition. Amazon Resale items do carry a standard return window, which reduces some risk.
How much more does the RTEX-24 cost than the RTEX-18? The RTEX-24 costs $549 compared to $438 for the RTEX-18, a difference of $111 for roughly 1.5 additional GPM of capacity and 6kW more power.
Does the Rheem RTEX-24 save money on electric bills? According to Rheem, citing Department of Energy figures, whole-home tankless models can save up to 34% on water heating costs compared to tank-type heaters. Actual savings depend on usage patterns and climate.
Why do prices for the Rheem RTEX-24 vary between retailers? Pricing varies based on retailer margins, current promotions, and whether you’re buying new, used, or a bundled version with additional parts. Always confirm you are looking at the 24kW “Whole Home” model specifically, since other RTEX sizes are priced differently.
Is the Rheem RTEX-24 worth the price compared to a tank water heater? For smaller households with moderate hot water demand, many owners report the RTEX-24 pays for itself over time through reduced standby energy loss, though the exact payback period depends on your electricity rates and usage.
Does the price include a warranty? Yes, standard manufacturer warranty coverage applies to new units purchased through Amazon or authorized retailers. Check Rheem’s warranty documentation for specific terms, since coverage can vary by part.
What additional costs should I budget for beyond the sticker price? Beyond the $549 unit price, budget for electrician labor (commonly $500 to $900 based on real reviewer-reported costs), potential panel or sub-panel upgrades, and basic plumbing fittings for the water connection.
References
- Amazon.com product listing for Rheem RTEX-24, including full RTEX family pricing comparison table and verified customer reviews, accessed July 2026: https://www.amazon.com/dp/B01MS9DVEE
- Rheem product page citation of U.S. Department of Energy savings figures for tankless water heaters, as displayed on Amazon manufacturer content, accessed July 2026