State T-H3-OS-N 1 (GTS-540-PEH 1-1) is a gas tankless water heater from State rated 5.8 GPM at a 0.95 UEF — 178 therms/yr certified use, 199k BTU/h input.
Also sold as the A. O. Smith T-H3-OS-N 1 (ACT-199O-P 1-1). This model is the same certified
hardware as the A. O. Smith T-H3-OS-N 1 (ACT-199O-P 1-1), published under a
different brand — full details, comparisons, and pricing live on that page. The
certified figures below are identical.
Efficiency
Uniform Energy Factor (UEF)
0.95
Annual gas use (natural gas)
178 therms/yr
Annual propane use
194.53 gal/yr
General
Fuel
Propane
Capacity
Max flow rate
5.8 GPM
Draw pattern
High
Minimum activation flow
1 GPM
Performance
Gas input rate
199 kBTU/h
Installation
Max current draw
5 A
Vent type
Power Vent
Vent size
3
Smart features
Smart / connected capable
No
Dimensions
Height
22 in
Width
18 in
Depth
11 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 State T-H3-OS-N 1 (GTS-540-PEH 1-1) at common temperature
rises (a typical shower uses about 2 GPM of mixed water):
Is the State T-H3-OS-N 1 (GTS-540-PEH 1-1) ENERGY STAR certified?
Yes, the State T-H3-OS-N 1 (GTS-540-PEH 1-1) holds a current ENERGY STAR certification for water heating efficiency (UEF 0.95).
How much does the State T-H3-OS-N 1 (GTS-540-PEH 1-1) cost to run per year?
About $525 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 State T-H3-OS-N 1 (GTS-540-PEH 1-1) use?
The State T-H3-OS-N 1 (GTS-540-PEH 1-1) uses Power Vent venting with 3 in vent connections. Matching the existing vent type is usually the cheapest replacement path.
Is the State T-H3-OS-N 1 (GTS-540-PEH 1-1) a smart water heater?
No, the State T-H3-OS-N 1 (GTS-540-PEH 1-1) is not connected-capable — it has no app connectivity or demand-response support.
