Rinnai RE199i
#10 in GasFull review
A dependable whole home heater for buyers who want Rinnai power at a lower price than a condensing model and have room for metal venting.
Amazon $1,280.79 Amazon $1,412.82$1,280.79
The Rinnai RE199i is the better tankless water heater overall, rated 4.0 to 3.4. The Rinnai RE199i leads on heating power. The ThermoMate RTC68iN wins on efficiency. The ThermoMate RTC68iN costs $180.80 less ($1,099.99 vs $1,280.79).
ThermoMate RTC68iN
#15 in GasFull review
A budget condensing heater for natural gas homes that want PVC venting and lower gas bills, if you can live with an unclear warranty.
ThermoMate $1,099.99$1,099.99
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 Rinnai RE199i for heating power (199,000 BTU/h vs 163,000 BTU/h).
- Choose the ThermoMate RTC68iN for efficiency (0.91 UEF vs 0.82 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 | Rinnai RE199i | ThermoMate RTC68iN |
|---|---|---|
| Overall rating | 4.0/5 | 3.4/5 |
| Value 35% | 57 $6.44 per 1,000 BTU/h ($1,280.79, 199,000 BTU/h) | 52 $6.75 per 1,000 BTU/h ($1,099.99, 163,000 BTU/h) |
| Heating power 25% | 100 199,000 BTU/h | 54 163,000 BTU/h |
| Efficiency 15% | 12 0.82 UEF | 69 0.91 UEF |
| Warranty 25% | 100 15-year heat exchanger warranty | 50 heat exchanger warranty not published (neutral score used) |
Specifications
| Rinnai RE199i | ThermoMate RTC68iN | |
|---|---|---|
| Heating | ||
| Fuel | Gas | Gas |
| Gas type | Natural gas or propane | Natural gas |
| Gas input | 10,400 to 199,000 BTU/h | 163,000 BTU/h |
| Max flow | 9.8 GPM | 9.4 GPM |
| UEF | 0.82 | 0.91 |
| Condensing | No | Yes |
| ENERGY STAR | No | - |
| Installation | ||
| Venting | Indoor | Indoor |
| Vent type | 3 in x 5 in concentric | PVC |
| Weight | 42.1 lb | 50 lb |
| Features | ||
| Built-in recirculation | No | No |
| Wi-Fi | No | No |
| Heat exchanger warranty | 15 years | - |
| Parts warranty | 5 years | - |