Upfront cost, ten-year running cost, the gas line question and the Energy Trust rebates — and an honest account of which households each one actually suits.
We install both, so we have no particular stake in the answer. What follows is the comparison we actually run on site, which is mostly about how long you are staying and what your gas line can carry.
| Gas tank | Gas tankless | |
|---|---|---|
| Installed price | $1,100–$1,900 | $1,800–$3,800 |
| Energy Trust rebate | None | Up to $400 |
| Typical life | 8–12 years | 20+ years |
| Running cost | Baseline | Roughly 20–30% less gas |
| Hot water | 50 gallons, then it runs out | Endless, within its flow rate |
| Space | A floor-standing tank | Wall-mounted, floor freed |
| Maintenance | Annual flush | Descale every 2–3 years |
| Failure mode | Leaks, eventually floods | Faults and stops; no stored water |
A tank keeps 50 gallons hot 24 hours a day whether you are home or not. That standby loss is the whole of the efficiency argument for tankless, and it is real — but it is a percentage of a bill that is not enormous to begin with. For a typical Portland household of three to four, the gas saving is meaningful but not dramatic.
The stronger financial argument is lifespan. Over a twenty-year window you are comparing one tankless unit against two tanks plus two installations. That is where the numbers actually tilt, and it is also why the answer depends so heavily on whether you are staying.
Are you in this house for ten more years? If yes, tankless usually wins on total cost. If no, you pay the premium and the next owner collects the saving. We will tell you which side of that line you are on rather than quoting whichever is bigger.
This is the part that catches people out, and it is the reason a phone quote for a tankless conversion is worth nothing. A 40-gallon gas tank draws around 40,000 BTU. A condensing tankless unit that can supply two showers draws 150,000–199,000 BTU.
If the existing line cannot deliver that at the appliance — which depends on pipe diameter, run length and what else is on the line — it has to be upsized. In an older Portland house with a long run from the meter, that can be a significant part of the job. It is measured on site, not assumed.
If you are on electricity rather than gas, this comparison is the wrong one — read the heat pump page instead, because that is where both the efficiency and the Oregon rebate actually are.
Yes — typically 20–30% less gas than a tank, because you are not reheating 50 gallons through the night. Whether that repays the higher install cost depends on how long you stay.
Often. A condensing tankless unit can want 150,000–199,000 BTU where the tank it replaces wanted 40,000. If the existing line cannot deliver that at the end of the run, it has to be upsized.
Twenty years and more with the descale done every two to three years, against eight to twelve for a tank.
No diagnostic fee, no trip charge, and a flat-rate price in writing before anything starts. If it is no hot water today, calling is faster than the form.
A real diagnosis and a flat-rate price in writing, anywhere in Portland, at no cost.