Carnot Labs, Inc Reservoir 50-Gallon is a heat pump (hybrid electric) water heater from Carnot Labs, Inc with a 47 gallon rated tank and a 75 gallon first-hour rating at a 3.53 UEF — 1404 kWh/yr certified use, 44.2 in tall.
Our take
Carnot Labs certifies the Reservoir under the High draw pattern — rare in the 50-gallon class, where Medium is the norm — with a 75-gallon first-hour rating that suits a 5+ person household. Its $239-a-year figure (1,404 kWh) is not directly comparable to Medium-draw rivals: the test delivers more hot water. UEF is 3.53, right at the class median. The 44.2-inch height is the second-shortest among integrated units here, with R-513A refrigerant (GWP ~630) and a 40 °F compressor cutoff. Not connected-capable, single badge, 240 V / 21.6 A.
Best for: Heavy daily demand in a height-limited space.
Trade-off: Median efficiency and no smart features from a single-badge newcomer.
Efficiency
Uniform Energy Factor (UEF)
3.53
Annual electricity use
1404 kWh/yr
Recovery efficiency
396.4 %
General
Fuel
Electric
Capacity
First-hour rating
75 gal
Rated storage volume
47 gal
Draw pattern
High
Heat pump
Heat pump type
240 Volt Integrated HPWH
Refrigerant (GWP)
R-513A (GWP:630)
Compressor low-temp cutoff
40 °F
Installation
Input voltage
240
Max current draw
21.6 A
Smart features
Smart / connected capable
No
Dimensions
Height
44.2 in
Diameter
18.9 in
Certification
ENERGY STAR certified
Yes
Who is the Carnot Labs, Inc Reservoir 50-Gallon for?
Its 75 gallon first-hour rating suits a
household of 5+ people under DOE sizing guidance.
Estimated running cost: about $239/year at the national
average electricity rate (1404 kWh/yr certified use).
Needs a 240 V circuit; at 21.6 A max draw plan for a 30 A breaker (NEC 125% continuous-load rule).
The heat pump compressor operates down to 40 °F ambient — below that, backup
elements take over.
Is the Carnot Labs, Inc Reservoir 50-Gallon ENERGY STAR certified?
Yes, the Carnot Labs, Inc Reservoir 50-Gallon holds a current ENERGY STAR certification for water heating efficiency (UEF 3.53).
How much does the Carnot Labs, Inc Reservoir 50-Gallon cost to run per year?
About $239 per year at national average energy rates, based on its certified annual energy use under the DOE test draw pattern. Your rate and usage change this figure.
What electrical circuit does the Carnot Labs, Inc Reservoir 50-Gallon need?
The Carnot Labs, Inc Reservoir 50-Gallon runs on a 240 V circuit drawing up to 21.6 A; per the NEC 125% continuous-load rule plan for at least a 30 A breaker (check the installation manual for the required circuit).
Is the Carnot Labs, Inc Reservoir 50-Gallon a smart water heater?
No, the Carnot Labs, Inc Reservoir 50-Gallon is not connected-capable — it has no app connectivity or demand-response support.
