Water Heater Gas Tankless
A.O. Smith Adapt+ Premium Condensing
The Adapt+ Premium Condensing gas tankless water heater delivers on-demand hot water with a UEF of 0.95 and up to 199,000 BTU. Features X3® Scale Prevention Technology, an integrated recirculation pump, and PVC venting flexibility. ENERGY STAR® certified. Available with integrated or optional-accessory X3 scale prevention in three BTU sizes.
UEF
0.95
Min BTU Input
9,000 BTU
Fuel
Natural Gas (LP convertible, kit included)
Voltage
120V
Amperes
5A
Vent Material
PVC, CPVC, ABS, Polypropylene
Model Comparison
6 models
Integrated 
Optional Accessory | Specification | Integrated | Optional Accessory | ||||
|---|---|---|---|---|---|---|
| Model | ATHR-160X3 100 | ATHR-180X3 100 | ATHR-199X3 100 | ATHR-160M 100 | ATHR-180M 100 | ATHR-199M 100 |
| Max Flow Rate | 4.8 GPM | 5.3 GPM | 5.9 GPM | 4.8 GPM | 5.3 GPM | 5.9 GPM |
| Height | 41.8" | 41.8" | 41.8" | 34" | 34" | 34" |
Shared Specifications
All models| UEF | 0.95 |
| Min BTU Input | 9,000 BTU |
| Fuel | Natural Gas (LP convertible, kit included) |
| Voltage | 120V |
| Amperes | 5A |
| Vent Material | PVC, CPVC, ABS, Polypropylene |
| Vent Size | 2 in (up to 75 ft) or 3 in (up to 150 ft) |
| Water Connection | 3/4 in |
| Connection Location | Bottom |
| Flue Diameter | 2" |
| width_in | 16.53" |
| shipping_weight_lbs | 125 lbs |
| Emissions | Ultra-Low NOx |
| ENERGY STAR® | Yes |
| Installation | Indoor or outdoor (outdoor kit sold separately) |
| Ignition | Electronic hot surface |
| warranty_heat_exchanger_years | 15 yr |
| warranty_parts_years | 5 yr |
| Max Cascade Units | 12 |
| Recirculation Pump | Integrated (X3 models) / Not included (M models) |