CO-Z JSD-24 vs Mizudo FDG-CS90: which uses less energy?
At the low draw pattern the Mizudo FDG-CS90 uses 91 therms a year and the CO-Z JSD-24 92 — 1 therms (1%) less, about 11 therms over ten years. Both are filed as a gas tankless unit, so the comparison holds. Enter your ZIP below to price the difference.
Side by side
Compared within one class only: models filed as a gas tankless unit at the low draw pattern.
| Figure | CO-Z JSD-24 | Mizudo FDG-CS90 |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.83 | 0.84 (better) |
| Energy use per year (therms) | 92 | 91 (better) |
| Max flow (GPM) | 3.1 | 2.3 |
| Installed cost range | $1,792–$2,743 | $1,839–$2,798 |
| ENERGY STAR certified | not matched | not matched |
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 below.
- The actual warranty term is printed in each model’s documentation, not in any registry.
Which should you pick?
- Pick the Mizudo FDG-CS90 if running cost matters most: it uses 1 therms less a year on the same test.
- Pick the CO-Z JSD-24 if you run more fixtures at once: it lists 3.1 GPM against 2.3.
- Neither if you need more than 3.1 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.
Each model on its own
-
CO-Z JSD-24
Its filed figures, class position and running cost on your ZIP.
-
Mizudo FDG-CS90
Its filed figures, class position and running cost on your ZIP.