A. O. Smith ACTH-199M-(N,P) 1 vs Lochinvar ATHR-180M 1 (LTHR-180M 1)
Both water heaters carry the same efficiency rating: UEF 0.95. The A. O. Smith ACTH-199M-(N,P) 1 sustains the higher flow (5.8 GPM vs 5.3 GPM under the DOE test).
| A. O. Smith ACTH-199M-(N,P) 1 | Lochinvar ATHR-180M 1 (LTHR-180M 1) | |
|---|---|---|
| Uniform Energy Factor (UEF) | 0.95 | 0.95 |
| Fuel | Natural Gas, Propane | Natural Gas, Propane |
| Max flow rate | 5.8 GPM | 5.3 GPM |
| Draw pattern | High | High |
| Annual gas use (natural gas) | 178 therms/yr | 178 therms/yr |
| Gas input rate | 199 kBTU/h | 180 kBTU/h |
| Max current draw | 5 A | 5 A |
| Vent type | Power Direct Vent, Power Vent | Power Vent, Power Direct Vent |
| Recovery efficiency | 97 % | 97 % |
| Smart / connected capable | No | No |
| Minimum activation flow | 1 GPM | 1 GPM |
| Annual propane use | 194.53 gal/yr | 194.53 gal/yr |
| Vent size | 3 / 2 | 3 / 2 |
| Width | 17 in | 17 in |
| Depth | 16 in | 16 in |
| ENERGY STAR certified | Yes | Yes |
Frequently asked questions
Which costs less to run, the A. O. Smith ACTH-199M-(N,P) 1 or the Lochinvar ATHR-180M 1 (LTHR-180M 1)?
They are effectively tied: both cost about $258/year at national average energy rates under the DOE test draw pattern.
Are the A. O. Smith ACTH-199M-(N,P) 1 and Lochinvar ATHR-180M 1 (LTHR-180M 1) both ENERGY STAR certified?
Yes — every water heater in this database is drawn from the U.S. EPA ENERGY STAR certified water heater datasets.