What should a tankless water heater cost installed?
Tankless costs two to three times a tank up front and pays back slowly. Here is the installed range, what pushes a quote to $9,000, and who it suits.
Call a licensed plumber
Hire a pro
$2,000 to $5,500
typical in the US, before local labor differences
Do it yourself
Not this one
licensed or specialized work
Always a licensed plumber, often with an electrician or a gas fitter. The unit is $1,000 to $2,500; the rest of the price is venting, a larger gas line, sometimes a 240 volt circuit, condensate drainage, the permit and the hours. A quote near the top of the range or above it is usually carrying one of those upgrades, and that is the line item to ask about.
Free, no account for the first question. The advisor knows your home's age, systems and region.
Why it costs what it costs
- Gas supply: most tankless units need a 3/4 inch gas line and more BTU than the old tank drew. Upsizing the line is the most common hidden cost.
- Venting: condensing units vent in PVC through a wall; non-condensing need stainless. Running new vent to the outside adds hours.
- Electrical: a whole-house electric tankless can need two or three new 40 amp circuits, which is a panel conversation before it is a water heater one.
When to stop and call someone
- Everything about this job. The decision you own is tank versus tankless, and the brand.
- A quote above $7,000 for a standard home deserves a second quote from a plumber who installs the same brand weekly.
- An existing tankless throwing error codes after a flush: the manufacturer's service line first, then a certified installer.
Questions people ask
- I was quoted $9,000 to install a tankless water heater. Is that high?
- It is above the typical installed range. It can be justified by a long gas line run, a panel upgrade for an electric unit, or two units in a large house. Ask for the quote broken into unit, gas or electrical work, venting and permit, and get a second number.
- Is tankless worth it over a tank?
- For a household that runs out of hot water, or one that will stay in the house 15 years, usually yes. For a couple who never runs out and might move in five years, a quality tank at a third of the price is the better buy.
- How long does a tankless last, and what maintenance does it need?
- About 20 years against 8 to 12 for a tank, provided it gets a descaling flush every year (every six months in hard water) and the inlet filter is cleaned. Skip the flushes and the error codes start.
- Gas or electric tankless?
- Gas for whole-house supply in most homes. Electric suits a small home, a point-of-use sink, or a house without gas, but check the panel capacity first.
What would it cost at your house?
Ranges above are national. Ask about your own home, or paste the quote you were given and we check it against the range. Free, no account for the first question.
More on water heaters
- What does a water heater expansion tank cost, and do I need one? · $250 to $500
- Do I need a plumber to flush my water heater, and what does it cost? · $75 to $250
- Is $250 fair to replace a water heater pilot assembly or thermocouple? · $120 to $350
- What does a water heater replacement cost? · $1,667 to $4,167
- The water heater guide: quote check, symptoms, how long yours will last
Published 2026-10-29. Source: Viorly's repair cost database, the same numbers behind its inspection report analysis and advisor. The DIY figure is parts at retail; the pro range is before local labor differences. Lowest listed price is $2,000.