A. O. Smith GT15TM-180X3-N 1

A. O. Smith GT15TM-180X3-N 1 is a gas tankless water heater from A. O. Smith rated 5.4 GPM at a 0.95 UEF.

Efficiency
Uniform Energy Factor (UEF) 0.95
Annual gas use (natural gas) 178 therms/yr
Recovery efficiency 96 %
Annual propane use 194.53 gal/yr
General
Fuel Natural Gas
Capacity
Max flow rate 5.4 GPM
Draw pattern High
Minimum activation flow 1 GPM
Performance
Gas input rate 180 kBTU/h
Installation
Max current draw 5 A
Vent type Power Direct Vent, Power Vent
Vent size 3 / 2
Smart features
Smart / connected capable No
Dimensions
Width 17.3 in
Depth 12 in
Certification
ENERGY STAR certified Yes

Real flow rate by climate

A tankless heater's usable flow depends on how far it must raise incoming water temperature. Sustained hot-water flow of the A. O. Smith GT15TM-180X3-N 1 at common temperature rises (a typical shower uses about 2 GPM of mixed water):

Temperature rise Climate Sustained flow Simultaneous showers
45 °F Warm climate (~75 °F groundwater) 5.4 GPM 2
55 °F Mild climate (~65 °F groundwater) 5.4 GPM 2
70 °F Cold climate (~50 °F groundwater) 4.9 GPM 2
77 °F DOE test condition 4.4 GPM 2

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Frequently asked questions

Is the A. O. Smith GT15TM-180X3-N 1 ENERGY STAR certified?

Yes, the A. O. Smith GT15TM-180X3-N 1 holds a current ENERGY STAR certification for water heating efficiency (UEF 0.95).

How much does the A. O. Smith GT15TM-180X3-N 1 cost to run per year?

About $258 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 venting does the A. O. Smith GT15TM-180X3-N 1 use?

The A. O. Smith GT15TM-180X3-N 1 uses Power Direct Vent, Power Vent venting with 3 / 2 in vent connections. Matching the existing vent type is usually the cheapest replacement path.

Is the A. O. Smith GT15TM-180X3-N 1 a smart water heater?

No, the A. O. Smith GT15TM-180X3-N 1 is not connected-capable — it has no app connectivity or demand-response support.

Sources