ThermoMate CZ750NG
#6 in GasFull review
A low cost indoor whole home heater for natural gas homes, but check the warranty with ThermoMate before buying.
Amazon $739.99$739.99
The ThermoMate CZ750NG is the better tankless water heater overall, rated 4.1 to 3.8. The ThermoMate CZ750NG leads on value and heating power. The Rinnai Sensei RX160i wins on efficiency. The ThermoMate CZ750NG costs $558.44 less ($739.99 vs $1,298.43).
Rinnai Sensei RX160i
#12 in GasFull review
A very efficient heater for a two bathroom home that does not need the full 199,000 BTU/h of the RX199i.
Amazon $1,298.43$1,298.43
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the ThermoMate CZ750NG for value ($3.72 per 1,000 BTU/h ($739.99, 199,000 BTU/h) vs $8.12 per 1,000 BTU/h ($1,298.43, 160,000 BTU/h)) and heating power (199,000 BTU/h vs 160,000 BTU/h).
- Choose the Rinnai Sensei RX160i for efficiency (0.97 UEF vs 0.81 UEF).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every gas tankless water heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | ThermoMate CZ750NG | Rinnai Sensei RX160i |
|---|---|---|
| Overall rating | 4.1/5 | 3.8/5 |
| Value 35% | 100 $3.72 per 1,000 BTU/h ($739.99, 199,000 BTU/h) | 36 $8.12 per 1,000 BTU/h ($1,298.43, 160,000 BTU/h) |
| Heating power 25% | 100 199,000 BTU/h | 51 160,000 BTU/h |
| Efficiency 15% | 6 0.81 UEF | 100 0.97 UEF |
| Warranty 25% | 50 heat exchanger warranty not published (neutral score used) | 100 15-year heat exchanger warranty |
Specifications
| ThermoMate CZ750NG | Rinnai Sensei RX160i | |
|---|---|---|
| Heating | ||
| Fuel | Gas | Gas |
| Gas type | Natural gas | Natural gas or propane |
| Gas input | 199,000 BTU/h | 15,000 to 160,000 BTU/h |
| Max flow | 8 GPM | 9 GPM |
| UEF | 0.81 | 0.97 |
| Condensing | No | Yes |
| ENERGY STAR | - | Yes |
| Installation | ||
| Venting | Indoor | Both |
| Vent type | 3 in OD vent | 2 in or 3 in PVC/CPVC/PP, or concentric |
| Weight | - | 54 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | - | 15 years |
| Parts warranty | - | 5 years |