What it delivers
The ThermoMate EH270 27 kW Electric Tankless Water Heater is a whole-house electric tankless rated at 27 kW on 240 volts. Its listing gives a maximum flow of 6.6 GPM.
Flow depends on how cold the incoming water is. Our estimate from its input: 4.1 GPM at a 45°F rise, falling to 2.6 GPM at 70°F, which is 1 shower at 2 GPM on a cold-climate winter day. Try your own inlet temperature.
At 240 volts 27 kW is about 112 amps. The maker calls for 3 x separate 40 Amp double-pole breakers. The requirement calculator shows it at 208 V too; an electrician confirms the panel.
No flue, no gas line and a compact box on the wall; the trade-off is that a cold winter inlet cuts its flow sharply.
Also on the listing: features: Self-Modulating, advanced water-and-electricity separation structure; connections: 3/4" npt; model: EH270.
The listing gives dimensions of 13.15 in (W) x 17.09 in (H) and a weight of 19 lb.
Right unit for this house?
Install it when
- 2 showers at once 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
- 27 kW
- Up to 6.6 GPM
- No venting or gas line
- Breakers stated by the maker
Trade-offs
- Draws about 112 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 | EH270 | Retailer |
|---|---|---|
| Dimensions (seller) | 13.15"W x 17.09"H | Retailer |
| Features (seller) | Self-Modulating, advanced water-and-electricity separation structure | Retailer |
| Power | 27 kW | Retailer |
| Voltage | 240 V | Retailer |
| Max flow (maker) | 6.6 GPM | Retailer |
| Product weight | 19 lb | Retailer |
| Breakers (maker) | 3 x separate 40 Amp double-pole breakers | Retailer |
| Connections | 3/4" npt | Retailer |
Rival units at this flow
More electric tankless water heaters rated for similar demand
- EcoSmart ECOS 18 Electric Tankless Water Heater
- Westinghouse WET-24K-G 24 kW Electric Tankless Water Heater
- Westinghouse ET018CA0G 18 kW Electric Tankless Water Heater
- Atmor AT-36N-XTP 36 kW Electric Tankless Water Heater
Full electric tankless water heaters spec grid · Every ThermoMate unit in the catalog
Final verdict
A practical whole-house electric tankless for 2 showers at once in mild climates.
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