Tankless water heater installation costs $2,500–$5,000 in the US, including the unit (~$1,000–$2,500) and labor. Whole-home gas units run highest; point-of-use electric units are cheapest. They last 20+ years (vs 10–12 for tank models) and reduce water-heating energy use by 24–34%. The 25C tax credit covers 30% up to $600. In Poland expect PLN 3,500–10,000; in the Netherlands €1,500–€4,500.
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Tankless water heater cost by type
| Type | Equipment (USD) | Installed (USD) |
|---|---|---|
| Gas, whole-home (180k–199k BTU) | $1,200–$2,500 | $2,800–$5,500 |
| Electric, whole-home (27 kW) | $700–$1,500 | $2,000–$4,000 |
| Point-of-use electric | $200–$500 | $400–$1,000 |
| Condensing gas (high efficiency) | $1,800–$3,500 | $3,500–$6,500 |
What affects the cost?
- Fuel switching — going gas-to-electric or vice versa adds $500–$2,500
- Venting — gas units need stainless flue or PVC for condensing models
- Gas line upgrade — many tankless units need 3/4" gas line (vs 1/2" for tanks)
- Electrical upgrade — whole-home electric tankless may need a 200A panel
- Water hardness — hard-water areas should add a softener or annual descale ($150–$300)
Costs by country
Cost in the United States
Most US homes pay $3,000–$4,500 for a gas whole-home tankless. Rinnai, Navien, and Rheem dominate. Pay attention to flow-rate sizing — undersized units can't run two showers at once. Federal 25C credit (30% up to $600) plus utility rebates ($150–$500) make payback faster.
How to save
- Right-size, don't oversize — bigger tankless = bigger gas line + more $
- Time with tank replacement — labor overlap saves $300–$800
- Annual descale — extends life and protects warranty
- Stack 25C credit + utility rebate — most homeowners miss the utility rebate
Frequently asked questions
How much does a tankless water heater cost installed?
Tankless (on-demand) water heater installation runs $2,500–$5,000 in the US — the unit ($1,000–$2,000) plus labor. Gas models cost more to install than electric because they often need new venting and a larger gas line. Replacing a tank with tankless adds retrofit work.
Is a tankless water heater worth it?
Tankless units cost more upfront than tank heaters ($2,500–$5,000 vs. $800–$2,500) but last 20+ years (vs. 10–12), never run out of hot water, and cut water-heating energy use 8–34% per the US DOE. They pay back best in low-to-moderate hot-water households.
Tankless vs tank water heater — what's the difference?
A tank heater stores and reheats 40–80 gallons continuously ($800–$2,500 installed); a tankless heats water on demand with no standby loss ($2,500–$5,000 installed). Tankless saves space and energy and lasts longer; tank heaters cost less upfront and handle high simultaneous demand more easily.