What it delivers
The Rheem RTEX-13 Electric Tankless Water Heater is a compact electric tankless rated at 13 kW on 240 volts. Its listing gives a maximum flow of 4.8 GPM.
Flow depends on how cold the incoming water is. Our estimate from its input: 2.0 GPM at a 45°F rise, falling to 1.3 GPM at 70°F, which is less than one 2 GPM shower on a cold-climate winter day. Size it to your fixtures.
At 240 volts 13 kW is about 54 amps. The requirement calculator shows it at 208 V too; an electrician confirms the panel.
It skips venting entirely, but the amps are the hurdle: check the panel before the plumbing.
Also on the listing: features: LED Display; material: Copper; model: RTEX-13.
The listing gives dimensions of 8.25 in (W) x 12.62 in (H) and a weight of 1.8 kg.
Right unit for this house?
Install it when
- Light use in mild climates
- Homes with no gas service
Look at another unit when
- Panels without spare capacity
- More than 1 shower at once in cold winters
Strengths and trade-offs
Strengths
- 13 kW
- Up to 4.8 GPM
- No venting or gas line
Trade-offs
- Flow drops with cold inlet water
- Breaker needs not stated
Install limits
- Figures are the maker's or seller's own. Flow at a rise is our estimate from the input; gas, venting and electrical work needs a licensed professional.
Rated performance
Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.
| Model number | RTEX-13 | Retailer |
|---|---|---|
| Dimensions (seller) | 8.25"W x 12.62"H | Retailer |
| Features (seller) | LED Display | Retailer |
| Power | 13 kW | Retailer |
| Voltage | 240 V | Retailer |
| Max flow (maker) | 4.8 GPM | Retailer |
| Product weight | 1.8 kg | Retailer |
| Material | Copper | Retailer |
Rival units at this flow
More electric tankless water heaters rated for similar demand
- Stiebel Eltron DHX 10-2 Trend 9.6 kW Electric Tankless Water Heater
- Westinghouse HEU-ET014KA1G-A2 14 kW Electric Tankless Water Heater
- Atmor AT-905-14TB 14 kW Electric Tankless Water Heater
- Stiebel Eltron DHX 12-2 Plus 12 kW Electric Tankless Water Heater
Full electric tankless water heaters spec grid · Every Rheem unit in the catalog
Final verdict
A practical compact electric tankless for light use in mild climates.
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