What it delivers
The Ranein RE18K 18 kW Electric Tankless Water Heater is a whole-house electric tankless rated at 18 kW on 240 volts. Its listing gives a maximum flow of 4.3 GPM.
At a 45°F rise (mild inlet water to a 120°F set point) it holds about 2.7 GPM, 1 shower at 2 GPM; in winter, at a 70°F rise, about 1.8 GPM, less than one 2 GPM shower. Try your own inlet temperature.
At 240 volts 18 kW is about 75 amps. The maker calls for 2 × 40 A double-pole breakers. A licensed electrician confirms the panel, the service and the wire before it goes in.
It skips venting entirely, but the amps are the hurdle: check the panel before the plumbing.
From the listing: connections: 3/4" npt; material: Stainless Steel; model: RE18K.
The listing gives dimensions of 13.8 in (W) x 18.7 in (H) and a weight of 7.9 kg.
Right unit for this house?
Install it when
- One shower at a time 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
- 18 kW
- Up to 4.3 GPM
- No venting or gas line
- Breakers stated by the maker
Trade-offs
- Draws about 75 A
- Winter flow is much lower
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 | RE18K | Retailer |
|---|---|---|
| Dimensions (seller) | 13.8"W x 18.7"H | Retailer |
| Features (seller) | Flame Failure Protection, LED Display, Lightweight, Overheat Protection | Retailer |
| Power | 18 kW | Retailer |
| Voltage | 240 V | Retailer |
| Max flow (maker) | 4.3 GPM | Retailer |
| Product weight | 7.9 kg | Retailer |
| Material | Stainless Steel | Retailer |
| Breakers (maker) | 2 × 40 A double-pole breakers | Retailer |
| Connections | 3/4" npt | Retailer |
Rival units at this flow
More electric tankless water heaters rated for similar demand
- WINTEMP YQ-WN18K 18 kW Electric Tankless Water Heater
- Orbek ET018 18 kW Electric Tankless Water Heater
- SIVUATEK TSB-180 18 kW Electric Tankless Water Heater
- VancEpic RE18K-C 18 kW Electric Tankless Water Heater
Full electric tankless water heaters spec grid · Every Ranein unit in the catalog
Final verdict
A solid whole-house electric tankless for one shower at a time in mild climates.
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