What it delivers
The Thermoflow UT15N3 4-Gallon Mini-Tank Water Heater is a mini-tank heater holding 4 gallons, rated at 1.5 kW on 120 volts.
It stores a few gallons of hot water right at the fixture, so the tap runs hot at once instead of waiting for the main heater.
At 120 volts it plugs into or wires to an ordinary household circuit, which is why mini tanks are a common retrofit.
Also on the listing: connections: 1/2 inch NPT; material: Stainless Steel; model: UT15N3.
The listing gives dimensions of 12.2 in (W) x 18 in (H).
Right unit for this house?
Install it when
- One sink far from the main heater
- Wet bars, garages and offices
Look at another unit when
- Showers or whole-house use
- Long continuous draws
Strengths and trade-offs
Strengths
- 4-gallon tank
- 120 V
- Hot water at the tap in seconds
Trade-offs
- Runs out after its stored gallons
- Needs room under the sink
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 | UT15N3 | Retailer |
|---|---|---|
| Tank | 4 gal | Retailer |
| Dimensions (seller) | 12.2"W x 18"H | Retailer |
| Features (seller) | Quickly Hot Water Supply, Compact Size Saves Space,Two Modes Optional, suitable for any season. | Retailer |
| Power | 1.5 kW | Retailer |
| Voltage | 120 V | Retailer |
| Material | Stainless Steel | Retailer |
| Connections | 1/2 inch NPT | Retailer |
Rival units at this flow
More point-of-use water heaters rated for similar demand
Final verdict
A practical mini-tank heater for one sink far from the main heater.
Buy this unit
Our links open this exact model's product page. Prices and stock change; check what's included before you order.
Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure



