American ATO-199B-N 1** vs Midea MGWH199ISPN: which uses less energy?
An asterisk in a model number stands for any character: one filing covers several variants.
At the high draw pattern the American ATO-199B-N 1** and the Midea MGWH199ISPN use the same energy, 206 therms a year each, on the same federal test. Both are filed as a gas tankless unit, so the comparison holds; what separates them is below. Enter your ZIP to price either one on your own rate.
Side by side
Compared within one class only: models filed as a gas tankless unit at the high draw pattern.
| Figure | American ATO-199B-N 1** | Midea MGWH199ISPN |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.82 | 0.82 |
| Energy use per year (therms) | 206 | 206 |
| Max flow (GPM) | 5 | 4.9 |
| Installed cost range NLR REMDB | $1,745–$2,687 | $1,745–$2,687 |
| CPSC recall naming it CPSC | none on file | none on file |
DOE CCD · 2026-09-19 NLR REMDB · 2026-04-01 CPSC · 2026-09-24
What it costs to run
Reliability
Not published: Reliability, failure rates and each model’s actual warranty term.
The registries these figures come from certify energy performance under a federal test; none of them records how long a unit lasts or how often it fails, so this page does not rank the two on reliability.
What is here instead:
- The filed efficiency, capacity and tank size of both models, side by side above.
- No CPSC recall on file names either model (list checked 2026-09-24).
- The actual warranty term is printed in each model’s documentation, not in any registry.
Which should you pick?
- Pick the American ATO-199B-N 1** if you run more fixtures at once: it lists 5 GPM against 4.9.
- Neither if you need more than 5 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.
Each model on its own
- American ATO-199B-N 1** 206 therms a year
- Midea MGWH199ISPN 206 therms a year