DoesTheMath

Fogatti FDG340IN-CS90-NG vs ORBEK HW100: which uses less energy?

At the low draw pattern the Fogatti FDG340IN-CS90-NG uses 93 therms a year and the ORBEK HW100 95 — 1 therms (1%) less, about 12 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.

Filed and computed figures
Figure Fogatti FDG340IN-CS90-NG ORBEK HW100
UEF (Uniform Energy Factor) 0.82 (better) 0.81
Energy use per year (therms) 93 (better) 95
Max flow (GPM) 2.2 2.5
Installed cost range $1,745–$2,687 $1,698–$2,632
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

Fogatti FDG340IN-CS90-NG: 93 therms a year ORBEK HW100: 95 therms a year

Fogatti FDG340IN-CS90-NG — 93 therms a year ORBEK HW100 — 95 therms a year

Fogatti FDG340IN-CS90-NG is 2 therms a year lower than ORBEK HW100.

DOE CCD · 2026-09-19

Report an issue with this number

Enter your ZIP to price both units on the same rate where you live.


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 Fogatti FDG340IN-CS90-NG if running cost matters most: it uses 1 therms less a year on the same test.
  • Pick the ORBEK HW100 if you run more fixtures at once: it lists 2.5 GPM against 2.2.
  • Neither if you need more than 2.5 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own