Product images: Amazon listings
Written from the listing's specs, not from our own use · How we rate
An element that only draws what it needs is the headline feature of the Rheem RTEX-27 (240V). It is a good match for hot water on demand without a gas line, at 5.8/10 on its documented specs.
| Brand | Rheem |
|---|---|
| Category | Electric tankless water heaters |
| Stated voltage | 240 V |
| ASIN | B01N5R9FQB |
Full listing title: Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
| Stated voltage | 240VFull listing title |
|---|
Two electric tankless heaters close to it on our rating, each with a dated price.
What it has going for it
Self-modulating. It draws only the power the flow and the setpoint need, instead of slamming every element on. Steadier temperature, and no wasted amps on a summer afternoon.
What the Rheem RTEX-27 (240V) listing names:
For the Rheem RTEX-27 (240V), the installation manual settles the breakers and the wire.
The online price is the heater alone. New double-pole breakers, heavy-gauge wire and the electrician's visit are extra, and an older panel may need an upgrade first.
The button opens the exact listing (ASIN B01N5R9FQB), where today's price, stock and seller apply.
Our take
The Rheem RTEX-27 (240V) is about an element that only draws what it needs, and it doesn't pretend to be more. No buyer reviews yet, so the Rheem RTEX-27 (240V) has to win you over on paper. Honestly, the catch: no word on the heating power or the breakers it needs. We'd pick it if you want the shower temperature to stay put; otherwise, put it next to the Rheem RTEX-13 (240V) first.
the unit on the wall next to the old tank's spot, water in and out. Under a sink or on the wall beside it, close to the tap it feeds.
Hot in a few seconds once the water in the pipes has passed, and the power steps up and down with the flow (self-modulating, per the listing). Set it, then leave it.
Colder inlet water means less hot flow from the same power. Low-flow shower heads stretch it further.
Clean the inlet screen and flush out scale on hard water. Our flushing and descaling guide has the routine.
Before the Rheem RTEX-27 (240V) ships, check your panel: the listing doesn't spell out the breakers, so ask before an electrician quotes the job.
Take a photo of the panel label (main breaker size and free slots) and send it to the electrician with the listing. Our electrical requirements guide explains what they will look for.
The flow an electric unit can deliver falls as the inlet water gets colder. Our flow-rate calculator does the sums for your region.
Hardwired 240 V work needs a licensed electrician and often a permit. Our install cost guide shows what usually ends up on the quote.
Hard water still builds up on the elements and the inlet screen. Our flushing and descaling guide covers the routine.
How the Rheem RTEX-27 (240V) stacks up against the closest alternative, the Rheem RTEX-13 (240V).
| Criterion | Rheem RTEX-27, 240V | Rheem RTEX-13, 240V |
|---|---|---|
| Our rating | 5.8/10 | 6.7/10 |
| Max flow | Not stated | 3.17 GPM |
| Breakers | Not stated | 54 A total |
Pick the Rheem RTEX-13 (240V) if you want our higher-rated option (6.7/10), with more stated flow (3.17 GPM).
We rate it 5.8/10 (fair). The rating comes from its documented listing alone, as no customer-review record is captured yet.
Its listing states self-modulating power. These are the seller's figures, not our measurements: how steady the temperature is in your shower and how it copes with your winter water can't be read from a listing.
Your panel: take a photo of the panel label (main breaker size and free slots) and send it to the electrician with the listing. Our electrical requirements guide explains what they will look for. Your winter flow: the flow an electric unit can deliver falls as the inlet water gets colder. Our flow-rate calculator does the sums for your region. The install: hardwired 240 V work needs a licensed electrician and often a permit. Our install cost guide shows what usually ends up on the quote. Scale: hard water still builds up on the elements and the inlet screen. Our flushing and descaling guide covers the routine.
We link to the exact listing on Amazon, where today's price, stock and seller apply. It is an affiliate link, and it has no effect on the rating.
No, we haven't used it ourselves. Everything on this page comes from its listing, read line by line and weighed with our published formula.