What it delivers
The ThermoMate SS-45 4.5 kW Point-of-Use Tankless Water Heater is a point-of-use electric tankless rated at 4.5 kW on 120 volts. Its listing gives a maximum flow of 1.0 GPM.
Worked out from its input, it delivers roughly 0.7 GPM when the water only has to rise 45°F, and 0.4 GPM at a 70°F winter rise: less than one 2 GPM shower in summer, less than one 2 GPM shower in winter. Try your own inlet temperature.
At 120 volts 4.5 kW is about 38 amps. The maker calls for 40A Double Pole Circuit Breaker. Whether your panel can carry it alongside heating and cooking loads is an electrician's call.
Point-of-use units go under or beside one sink, where a short pipe run means hot water in seconds.
Other listed details: connections: 1/2"npt; model: SS-45.
The listing gives dimensions of 10.95 in (W) x 2.52 in (H).
Right unit for this house?
Install it when
- One sink or a low-flow shower
- A far bathroom with a long wait for hot water
Look at another unit when
- Whole-house hot water
- Kitchen sinks at full flow in cold climates
Strengths and trade-offs
Strengths
- 4.5 kW
- Up to 1.0 GPM
- No venting or gas line
- Breakers stated by the maker
Trade-offs
- Flow drops with cold inlet water
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 | SS-45 | Retailer |
|---|---|---|
| Dimensions (seller) | 10.95"W x 2.52"H | Retailer |
| Features (seller) | Self-modulating Power, Cast Aluminum Heating Element, Stainless Steel Water Tube, Touch Control Panel, Waterproof Self-modulating Power, Cast Aluminum Heating Element, Stainless Steel Water Tube, Touch Control Panel, Waterproof | Retailer |
| Power | 4.5 kW | Retailer |
| Max flow (maker) | 1.0 | Retailer |
| Voltage | 120v | Retailer |
| Breakers (maker) | 40A Double Pole Circuit Breaker | Retailer |
| Connections | 1/2"npt | Retailer |
Rival units at this flow
More point-of-use water heaters rated for similar demand
- EcoSmart POU 4T 3.5 kW Point-of-Use Tankless Water Heater
- Ranein RE8K-U 8 kW Point-of-Use Tankless Water Heater
- ThermoMate ET060 6 kW Point-of-Use Tankless Water Heater
- Eemax EEM12004 4 kW Point-of-Use Tankless Water Heater
Full point-of-use water heaters spec grid · Every ThermoMate unit in the catalog
Final verdict
A sensible point-of-use electric tankless for one sink or a low-flow shower.
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