Electric tankless water heaters, under 1.0 gallon per minute

223 basic models from 23 brands, certified below 1.0 gallon per minute at a 67°F rise.

Basic models: 22323 brands
Advertised flows at least 1.5 times the certified flow: 74of 78No rise stated

Of these 223 models, 223 were tested for very small hot water use. The highest efficiency (UEF) on that test is 1.05, reached by one of 223 models.

Of the 337 electric tankless models on this site, 223 are in the under 1.0 gallon per minute group. Between them, the 223 models here carry 23 brand names.

On the very small hot water use test, UEF runs from 0.91 to 1.05 by model. Warmed by 67°F in the test, flow is 0.2 to 0.9 gallons per minute by model.

Makers and stores list a flow without a temperature rise for 66 of these models. Makers and stores gave at least 1.5 times the certified flow in 74 of 78 claims. Makers and stores print 44 UEF figures for 44 of these models. Of those 44 UEF figures, 10 differ from the certified UEF.

Certified figures by basic model

Sorted by flow, lowest first, then by UEF, highest first.

Electric tankless water heaters, under 1.0 gallon per minute: certified figures by basic model
Basic model	Flow at a 67°F rise (gal/min)	UEF	Draw pattern
Aquapower Mini 2-1	0.2	0.99	Very small
Stiebel Eltron Mini 2-1	0.2	0.99	Very small
Aquapower Mini-E 2.5-1	0.2	0.97	Very small
Stiebel Eltron Mini-E 2.5-1	0.2	0.97	Very small
EEMAX SPEX1812T	0.2	0.96	Very small
EEMAX SPEX2412T	0.2	0.96	Very small
Rheem SPEX1812T	0.2	0.96	Very small
Rheem SPEX2412T	0.2	0.96	Very small
EEMAX SPEX1812	0.2	0.95	Very small
EEMAX SPEX2412	0.2	0.95	Very small
KWICKSHOT TEF024V120	0.2	0.95	Very small
Rheem SPEX1812	0.2	0.95	Very small
Rheem SPEX2412	0.2	0.95	Very small
A. O. Smith UPVA-18K 1**	0.2	0.94	Very small
State UPVA-18K 1**	0.2	0.94	Very small
A. O. Smith UPVA-24K 1**	0.2	0.93	Very small
State UPVA-24K 1**	0.2	0.93	Very small
Stiebel Eltron DHC-E 3-1 Trend	0.3	0.99	Very small
Stiebel Eltron DHC 3-1 Trend	0.3	0.98	Very small
Aquapower DHC 3-2	0.3	0.97	Very small
Aquapower Mini -E 3-1	0.3	0.97	Very small
Aquapower Mini-E 2-1	0.3	0.97	Very small
EEMAX SPEX3208	0.3	0.97	Very small
EEMAX SPEX3208T	0.3	0.97	Very small
EEMAX SPEX3277T	0.3	0.97	Very small
EEMAX SPEX35T	0.3	0.97	Very small
KWICKSHOT TEF030V208	0.3	0.97	Very small
Rheem SPEX3208	0.3	0.97	Very small
Rheem SPEX3208T	0.3	0.97	Very small
Rheem SPEX3277T	0.3	0.97	Very small
Rheem SPEX35T	0.3	0.97	Very small
Stiebel Eltron DHC 3-2	0.3	0.97	Very small
Stiebel Eltron Mini -E 3-1	0.3	0.97	Very small
Stiebel Eltron Mini-E 2-1	0.3	0.97	Very small
Aquapower Mini 2.5-1	0.3	0.96	Very small
EEMAX SPEX3012	0.3	0.96	Very small
EEMAX SPEX3012T	0.3	0.96	Very small
EEMAX SPEX3512T	0.3	0.96	Very small
KWICKSHOT TEF030V120	0.3	0.96	Very small
Rheem SPEX3012	0.3	0.96	Very small
Rheem SPEX3012T	0.3	0.96	Very small
Rheem SPEX3512T	0.3	0.96	Very small
Stiebel Eltron Mini 2.5-1	0.3	0.96	Very small
ECOSMART ECO POU 3.5	0.3	0.95	Very small
EEMAX ECO POU 3.5	0.3	0.95	Very small
EEMAX SPEX3277	0.3	0.95	Very small
KWICKSHOT TEF030V277	0.3	0.95	Very small
Rheem ECO POU 3.5	0.3	0.95	Very small
Rheem SPEX3277	0.3	0.95	Very small
Shenzhen Cansirong Trading Co., Ltd RX-021	0.3	0.95	Very small
EEMAX SPEX3512	0.3	0.94	Very small
KWICKSHOT TEF035V120	0.3	0.94	Very small
Rheem AM004120T	0.3	0.94	Very small
Rheem SPEX3512	0.3	0.94	Very small
A. O. Smith UPVA-30K 1**	0.3	0.93	Very small
Aquapower DHC 3-1	0.3	0.93	Very small
Aquapower Mini 3-1	0.3	0.93	Very small
EEMAX AM004120T	0.3	0.93	Very small
Fogatti ET003	0.3	0.93	Very small
Mizudo ET003	0.3	0.93	Very small
RELIANCE WATER HEATERS UPVA-30K 1**	0.3	0.93	Very small
State UPVA-30K 1**	0.3	0.93	Very small
Stiebel Eltron DHC 3-1	0.3	0.93	Very small
Stiebel Eltron Mini 3-1	0.3	0.93	Very small
Westinghouse ET003	0.3	0.93	Very small
GE GE04SNLPDG01	0.3	0.91	Very small
Stiebel Eltron DHC 3.5-1 Trend	0.4	0.99	Very small
Stiebel Eltron DHC-E 3.5-1 Trend	0.4	0.99	Very small
Aquapower Mini-E 4-2	0.4	0.98	Very small
EEMAX SPEX4208T	0.4	0.98	Very small
Rheem SPEX4208T	0.4	0.98	Very small
Stiebel Eltron Mini-E 4-2	0.4	0.98	Very small
EEMAX SPEX4208	0.4	0.97	Very small
EEMAX SPEX4277T	0.4	0.97	Very small
EEMAX SPEX48T	0.4	0.97	Very small
KWICKSHOT TEF041V208	0.4	0.97	Very small
Rheem SPEX4208	0.4	0.97	Very small
Rheem SPEX4277T	0.4	0.97	Very small
Rheem SPEX48T	0.4	0.97	Very small
Aquapower Mini-E 3.5-1	0.4	0.96	Very small
EEMAX SPEX4277	0.4	0.96	Very small
KWICKSHOT TEF041V277	0.4	0.96	Very small
Rheem SPEX4277	0.4	0.96	Very small
Stiebel Eltron Mini-E 3.5-1	0.4	0.96	Very small
Aquapower DHC 4-2	0.4	0.95	Very small
Aquapower Mini 4-2	0.4	0.95	Very small
EEMAX SPEX35	0.4	0.95	Very small
KWICKSHOT TEF035V240	0.4	0.95	Very small
Rheem SPEX35	0.4	0.95	Very small
Stiebel Eltron DHC 4-2	0.4	0.95	Very small
Stiebel Eltron Mini 4-2	0.4	0.95	Very small
Ariston AURES SM 3 CB 110V US*	0.4	0.94	Very small
Bosch TR4000C-3*	0.4	0.94	Very small
EEMAX AM004277T	0.4	0.94	Very small
Rheem AM004277T	0.4	0.94	Very small
A. O. Smith UPVA-40Y 1**	0.4	0.93	Very small
Aquapower Mini 3.5-1	0.4	0.93	Very small
State UPVA-40Y 1**	0.4	0.93	Very small
Stiebel Eltron Mini 3.5-1	0.4	0.93	Very small
A. O. Smith UPVA-35E 1**	0.4	0.92	Very small
A. O. Smith UPVA-35K 1**	0.4	0.92	Very small
American UPVA-35K 1**	0.4	0.92	Very small
State UPVA-35E 1**	0.4	0.92	Very small
State UPVA-35K 1**	0.4	0.92	Very small
ThermoMate ET045	0.5	1.05	Very small
ECOTOUCH ECO65B	0.5	0.98	Very small
Aquapower DHC 5-2	0.5	0.97	Very small
ECOTOUCH ECO55W	0.5	0.97	Very small
EEMAX SPEX55T	0.5	0.97	Very small
KWICKSHOT TET055V240	0.5	0.97	Very small
Rheem SPEX55T	0.5	0.97	Very small
Stiebel Eltron DHC 5-2	0.5	0.97	Very small
Bradford White CTEH005********	0.5	0.96	Very small
EEMAX AM005240T	0.5	0.96	Very small
EEMAX SPEX48	0.5	0.96	Very small
KWICKSHOT TEF048V240	0.5	0.96	Very small
Laars LCTEH005********	0.5	0.96	Very small
Laars LCTEV005********	0.5	0.96	Very small
Rheem AM005240T	0.5	0.96	Very small
Rheem SPEX48	0.5	0.96	Very small
Aquapower DHC 4-3	0.5	0.95	Very small
Stiebel Eltron DHC 4-3	0.5	0.95	Very small
ECOSMART ECO POU 6	0.5	0.94	Very small
EEMAX ECO POU 6	0.5	0.94	Very small
Rheem ECO POU 6	0.5	0.94	Very small
A. O. Smith UPVA-55Y 1**	0.5	0.93	Very small
State UPVA-55Y 1**	0.5	0.93	Very small
A. O. Smith UPVA-45E 1**	0.5	0.92	Very small
A. O. Smith UPVA-55E 1**	0.5	0.92	Very small
RELIANCE WATER HEATERS UPVA-55E 1**	0.5	0.92	Very small
State UPVA-45E 1**	0.5	0.92	Very small
State UPVA-55E 1**	0.5	0.92	Very small
GE GE06SNHPDG01	0.5	0.91	Very small
Aquapower Mini-E 6-2	0.6	0.98	Very small
Stiebel Eltron DHC 6-2 Trend	0.6	0.98	Very small
Stiebel Eltron DHC-E 6-2 Trend	0.6	0.98	Very small
Stiebel Eltron Mini-E 6-2	0.6	0.98	Very small
EEMAX SPEX60T	0.6	0.97	Very small
EEMAX SPEX65T	0.6	0.97	Very small
KWICKSHOT TET060V277	0.6	0.97	Very small
KWICKSHOT TET065V240	0.6	0.97	Very small
Rheem SPEX60T	0.6	0.97	Very small
Rheem SPEX65T	0.6	0.97	Very small
Aquapower DHC 6-2	0.6	0.96	Very small
EEMAX SPEX55	0.6	0.96	Very small
EEMAX SPEX60	0.6	0.96	Very small
KWICKSHOT TEF055V240	0.6	0.96	Very small
KWICKSHOT TEF060V277	0.6	0.96	Very small
Rheem SPEX55	0.6	0.96	Very small
Rheem SPEX60	0.6	0.96	Very small
Stiebel Eltron DHC 6-2	0.6	0.96	Very small
Bradford White CTEH006********	0.6	0.95	Very small
EEMAX AM007240T	0.6	0.95	Very small
Laars LCTEH006********	0.6	0.95	Very small
Laars LCTEV006********	0.6	0.95	Very small
Rheem AM007240T	0.6	0.95	Very small
Aquapower Mini 6-2	0.6	0.94	Very small
Stiebel Eltron Mini 6-2	0.6	0.94	Very small
Chronomite SR	0.2–0.7	0.94–0.99	Very small
Stiebel Eltron DHC 8-2 Trend	0.7	0.99	Very small
EEMAX SPEX8208T	0.7	0.98	Very small
KWICKSHOT TET083V208	0.7	0.98	Very small
Rheem SPEX8208T	0.7	0.98	Very small
EEMAX SPEX75T	0.7	0.97	Very small
KWICKSHOT TET075V240	0.7	0.97	Very small
Rheem SPEX75T	0.7	0.97	Very small
Aquapower DHC 8-2	0.7	0.96	Very small
Aquapower DHC-E 8	0.7	0.96	Very small
Ariston AURES SM 6.5 240V US*	0.7	0.96	Very small
Bosch TR4000C-6*	0.7	0.96	Very small
ECOSMART ECO 8	0.7	0.96	Very small
EEMAX ECO 8	0.7	0.96	Very small
EEMAX SPEX65	0.7	0.96	Very small
KWICKSHOT TEF065V240	0.7	0.96	Very small
Rheem ECO 8	0.7	0.96	Very small
Rheem SPEX65	0.7	0.96	Very small
Stiebel Eltron DHC 8-2	0.7	0.96	Very small
Stiebel Eltron DHC-E 8	0.7	0.96	Very small
Chronomite CM	0.7	0.94	Very small
Mizudo ET006	0.7	0.94	Very small
Mizudo ET008	0.7	0.94	Very small
A. O. Smith UPVA-70E 1**	0.7	0.92	Very small
State UPVA-70E 1**	0.7	0.92	Very small
EEMAX SPEX80T	0.8	0.98	Very small
KWICKSHOT TET080V277	0.8	0.98	Very small
Rheem SPEX80T	0.8	0.98	Very small
Stiebel Eltron DHC-E 8-2 Trend	0.8	0.98	Very small
EEMAX AM008277T	0.8	0.96	Very small
EEMAX SPEX75	0.8	0.96	Very small
EEMAX SPEX80	0.8	0.96	Very small
EEMAX SPEX8208	0.8	0.96	Very small
KWICKSHOT TEF075V240	0.8	0.96	Very small
KWICKSHOT TEF080V277	0.8	0.96	Very small
KWICKSHOT TEF083V208	0.8	0.96	Very small
Rheem AM008277T	0.8	0.96	Very small
Rheem SPEX75	0.8	0.96	Very small
Rheem SPEX80	0.8	0.96	Very small
Rheem SPEX8208	0.8	0.96	Very small
A. O. Smith UPVA-80Y 1**	0.8	0.94	Very small
State UPVA-80Y 1**	0.8	0.94	Very small
A. O. Smith UPVA-90E 1**	0.8	0.93	Very small
American UPVA-90E 1**	0.8	0.93	Very small
RELIANCE WATER HEATERS UPVA-90E 1**	0.8	0.93	Very small
State UPVA-90E 1**	0.8	0.93	Very small
VEVOR R1T-80	0.8	0.93	Very small
GE GE08SNHPDG01	0.8	0.91	Very small
EEMAX SPEX90T	0.9	0.98	Very small
EEMAX SPEX95T	0.9	0.98	Very small
KWICKSHOT TET090V277	0.9	0.98	Very small
KWICKSHOT TET095V240	0.9	0.98	Very small
Rheem SPEX90T	0.9	0.98	Very small
Rheem SPEX95T	0.9	0.98	Very small
EEMAX AM010240T	0.9	0.96	Very small
EEMAX SPEX90	0.9	0.96	Very small
EEMAX SPEX95	0.9	0.96	Very small
KWICKSHOT TEF090V277	0.9	0.96	Very small
KWICKSHOT TEF095V240	0.9	0.96	Very small
Rheem AM010240T	0.9	0.96	Very small
Rheem SPEX90	0.9	0.96	Very small
Rheem SPEX95	0.9	0.96	Very small
Aquapower DHC 9-3	0.9	0.95	Very small
Stiebel Eltron DHC 9-3	0.9	0.95	Very small
Bosch TR4000C-8*	0.9	0.92	Very small

UEF is the uniform energy factor. A UEF compares only between models with the same draw pattern. A range means the models under one basic model differ. A dash means no such figure.

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Updated Oct 2, 2026 · Methodology

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