Shopping for a tankless hot water heater starts with a retail price, then the quote grows around it. Gas-line sizing, venting, electrical capacity, permits, and the work of removing a storage tank often decide the final number. A useful budget separates equipment from installation, applies a 2026 planning range to the right scenario, recognizes the federal-credit cutoff, and uses a quote checklist and payback calculation.
Last reviewed: 2026-09-03 (Pacific time)
This is a planning guide, not tax, plumbing, electrical, or code advice. A licensed professional should size and install the equipment. Incentive eligibility and current terms come from the program administrator.
Tankless water heater cost at a glance
Published national cost guides put whole-home tankless projects in a wide band. HomeGuide's 2026 data lists $1,400 to $5,600 installed across electric, propane, and natural-gas systems. ConsumerAffairs' installation breakdown puts most complete installations at $2,400 to $5,400, with a full fuel conversion reaching $10,500 when a home needs major infrastructure work. Point-of-use units need their own itemized scope, so the whole-home figures below are not a price benchmark for one fixture.
Use these as first-pass budgets, not promises of what a contractor in your area will charge:
| Project situation | Planning range, installed | What the range assumes |
|---|---|---|
| Whole-home electric tankless | $1,400–$3,000 | Equipment and ordinary installation, with no major service upgrade. |
| Whole-home natural-gas tankless | $2,100–$5,600 | Equipment, labor, venting, and ordinary gas work. |
| Whole-home propane tankless | $1,600–$4,500 | Equipment, labor, venting, and ordinary propane work. |
| Same-fuel tank-to-tankless retrofit | $3,900–$6,000 | A storage-tank replacement that needs new mounting, connections, and some fuel or vent work. |
| Electric tankless with electrical upgrade | $4,500–$8,000 | A whole-home unit plus new circuits or panel work. |
| Full fuel conversion or major relocation | $6,000–$10,500 | New fuel service, major venting or electrical work, and more involved access or relocation. |
The ranges overlap because the word “installation” means different things on different websites. Do not add every row together. Match your project to the row that describes the work you actually need, then compare itemized local quotes.
What your installation quote should include
The heater itself is only one line. HomeGuide estimates that the unit is about 40% to 45% of the total project. ConsumerAffairs lists common gas-line, venting, electrical, condensate, and permit allowances, which support the planning ranges below. A complete quote should identify each of these items:
| Quote line | Typical planning amount | When it appears |
|---|---|---|
| Tankless unit | $600–$2,600 | Capacity, fuel, condensing design, controls, and warranty determine the price. |
| Installation labor | $600–$2,500 | Plumber and electrician time, startup, testing, and cleanup. |
| Valves, connectors, pipe, and fittings | $150–$300 | New isolation valves, unions, pressure relief piping, and connection materials. |
| Permit and inspection | $50–$500 | Local plumbing, gas, or electrical permits and required inspections. |
| Gas line or meter work | $500–$2,000 | A tankless burner can need a larger supply than the old storage heater. |
| New gas venting | $300–$1,500 | A tank's draft-vent pipe generally cannot be reused for a sealed-combustion unit. |
| Condensate drain or neutralizer | $200–$500 | Common with high-efficiency condensing gas models. |
| Electrical outlet or dedicated circuit | $250–$900 | Model- and code-specific. Whole-home electric units often need dedicated high-amperage circuits; some gas units need a receptacle for controls. |
| Panel or service upgrade | $1,000–$3,000 | Needed only when the home's load calculation cannot support the new demand. |
| Removal and disposal of the old tank | $75–$500 | Draining, carrying out, disposal, and any access repairs. |
These figures are national planning data from cost guides, so your market may differ. More importantly, the lines can overlap. For example, a quote may include fittings in the labor charge, and a panel upgrade may include the new circuit. Ask the contractor to show the scope once, with no hidden duplicate allowances.
A quote that says “standard installation” should define that phrase. Ask whether it includes the permit, inspection, vent termination, condensate disposal, gas-line sizing, required electrical outlet or circuit, startup, and removal of the old heater.
Gas versus electric: why the price changes
Electric tankless
The unit and basic labor are often less expensive because there is no combustion vent or gas line. A whole-home electric model can still draw a large amount of power, however. Some homes need several 240-volt circuits or a service upgrade, which can erase the initial price advantage. Have an electrician perform a load calculation before you choose a model. Do not assume that a 200-amp panel has enough spare capacity.
DOE describes a point-of-use unit as a small tankless heater for one to three fixtures or appliances at the point of demand. That makes it a different project from a whole-home replacement. Price this scope separately: several units mean more equipment and electrical work.
Gas or propane tankless
Gas models usually deliver more hot water at one time, but the installation has more parts. The unit may need a larger gas line, a new sealed vent, combustion-air clearances, a 120-volt receptacle for controls, and a condensate drain if it is a condensing model. Electrical requirements are model- and code-specific; a dedicated high-amperage circuit is mainly an electric whole-home issue. ENERGY STAR explains that a condensing unit uses a second heat exchanger and requires a dedicated vent and condensate drain.
For a gas unit, the installation manual specifies the maximum input in British thermal units per hour, gas-line diameter, vent material, vent length, and termination location. A high-capacity unit in a utility room far from an exterior wall can cost much more than an outdoor model with a short run.
Size the unit by flow and temperature rise
Tankless heaters are rated in gallons per minute (GPM), not by storage gallons. The correct size depends on the maximum hot-water flow you may use at the same time and the temperature rise from your cold-water inlet to your setpoint. The U.S. Department of Energy's sizing guidance calls for both calculations.
For a simple illustration, two 2.5-GPM showers plus a 1.9-GPM dishwasher represent about 6.9 GPM of potential simultaneous flow. The required capacity is lower if those uses do not overlap and higher if other fixtures join in. Cold winter inlet water also requires a larger temperature rise, which reduces the GPM a given model can deliver.
Give the installer:
- The number of occupants and bathrooms.
- The fixtures and appliances that commonly run together.
- Your incoming-water temperature or local winter design temperature.
- The desired outlet temperature, usually around 120°F for residential use.
- Any low-flow fixtures or periods when only a trickle runs.
Ask for the model's output at your required temperature rise, not its largest number in a marketing table. A unit that is too small may reduce outlet temperature when demand peaks. A unit that is much too large costs more and may cycle poorly at low flow.
Cost add-ons that surprise homeowners
The first quote often changes after a site visit. These additions move the number most often:
- Gas line and meter. A tankless burner can demand a much larger burst than a storage heater, so the line or utility meter may need to be upsized.
- Venting. Model-approved venting replaces an incompatible existing tank vent. Long runs, wall or roof penetrations, and snow-clearance work add labor.
- Electrical capacity. Whole-home electric models can need several high-amperage circuits. Price the circuits, panel, and service work separately.
- Condensate. A condensing gas model may need a drain, neutralizer, or pump, depending on the equipment and drainage route.
- Water quality. Mineral scale restricts flow. DOE guidance says flushing frequency can range from twice a year to once every three years, depending on the model, water hardness, and use. Include service in your ownership budget.
- Access and relocation. Wall repair, longer water runs, or a difficult tank removal can turn a short job into a full day or multiple visits.
Ask what physical work triggers each allowance and whether the permit and inspection are included.
Federal tax credits and rebates in 2026
There is no federal Energy Efficient Home Improvement Credit under section 25C for a tankless water heater placed in service in 2026. The Internal Revenue Service says the credit is not allowed for property placed in service after December 31, 2025. ENERGY STAR's tax-credit page also lists the gas-tankless credit as effective only through December 31, 2025.
Under the prior rule, qualifying natural-gas or propane tankless property placed in service by December 31, 2025 could qualify for 30% of eligible costs, up to $600, if it met the Consortium for Energy Efficiency (CEE) highest-efficiency tier in effect at the start of 2025. ENERGY STAR identifies a Uniform Energy Factor (UEF) of at least 0.95 for eligible tankless gas models. A 2025 claim also required the manufacturer's qualified manufacturer identification number (QMID) for the model on the 2025 Form 5695. Those historical rules do not create a credit for property placed in service in 2026.
Local offers can still change the budget. For example, UGI offers a $400 rebate to qualifying Pennsylvania residential gas customers who install an ENERGY STAR certified natural-gas tankless heater by September 30, 2026, pending available funds. UGI requires the application within 90 days of installation. This is a local example, not a national assumption.
Use the ENERGY STAR Rebate Finder to locate utility, state, and local offers by ZIP code. Official program terms determine the service territory, exact model, installation date, contractor requirements, pre-approval, application deadline, and funding status. Include a rebate in your budget only when the written terms establish that your project qualifies. Watt Wallet's incentive finder helps you start with state and utility offers.
If you are considering a heat pump water heater instead of a tankless unit, the incentives and installation constraints are different. Our heat pump water heater cost guide separates its electrical, room-fit, and rebate questions.
Is tankless worth the cost?
DOE's 2022 Energy Saver guide says most storage water heaters last 10 to 15 years. ENERGY STAR lists a tankless life expectancy of about 20 years with appropriate maintenance. The energy advantage is real, but it is not the same for every household. DOE reports that gas on-demand heaters can be 24% to 34% more efficient than storage heaters in homes using 41 gallons or less of hot water per day. At about 86 gallons per day, the gas-tankless advantage falls to 8% to 14%. Read the DOE figures in context before applying a generic percentage to your bill.
ENERGY STAR estimates that a certified gas tankless heater saves a family of four about $95 per year versus a standard gas storage model. If the tankless conversion adds $2,000 over the replacement tank you would otherwise buy, $2,000 divided by $95 is a simple payback of about 21 years. A local rebate, higher usage, lower installation premium, or a longer stay can change the result. Maintenance and financing costs push the payback in the other direction.
Use this screen:
-
- simple payback = (tankless installed price - realistic alternative price - confirmed rebates)
- ÷ estimated annual operating savings
-
Use the annual energy consumption on each model's yellow EnergyGuide label, then apply your utility's rate and the same usage assumption to both options. The Federal Trade Commission explains that EnergyGuide operating costs use typical use and national average energy prices, so your actual bill will differ.
Tankless is more likely to fit when:
- You are replacing a failed or nearly failed gas heater and the gas line and vent route are easy to adapt.
- Continuous hot water and saved floor space matter more than the lowest upfront price.
- You are building or remodeling and can plan the vent, gas, plumbing, and electrical paths before finishes are installed.
- You expect to stay long enough to use the longer service life.
Compare another option first when:
- You are replacing an electric tank and a whole-home electric tankless model would require a panel or service upgrade.
- Your main goal is lower electricity use. A heat pump water heater can be two to three times as efficient as a standard electric heater, though it needs room, airflow, condensate drainage, and suitable recovery capacity.
- Your household has modest demand and a point-of-use unit for a remote fixture, or a standard storage replacement, meets the actual need.
How to compare tankless quotes
Send every bidder the same project information and ask for these lines in the written proposal:
- Exact model number, fuel, condensing design, rated GPM at your temperature rise, UEF, warranty, equipment price, and labor.
- Fittings, isolation valves, pressure-relief piping, startup testing, water-line changes, recirculation equipment, wall repair, access work, and old-unit removal.
- Gas-line sizing, vent material and termination, combustion-air provisions, and condensate details for gas models.
- Circuit count and size, panel or service work, disconnects, and permits for electric models.
- Permit holder, inspection timing, labor warranty, and every incentive assumption, including who applies and when the money arrives.
Keep three totals while you compare:
- Gross installed price: all equipment and work in the contract.
- Amount due at installation: gross price minus discounts or rebates shown on the invoice.
- Eventual net cost: amount due plus financing interest and fees, minus rebates that arrive later.
Do not choose the lowest “after incentives” number until the bids have the same equipment, scope, and payment timing. Watt Wallet's guide to comparing rebates, tax credits, and installer quotes gives you a repeatable worksheet for that comparison.
FAQ
How much does a tankless water heater cost installed?
A whole-home electric unit commonly falls around $1,400–$3,000 installed. Natural-gas units commonly run $2,100–$5,600, while propane units run $1,600–$4,500. A tank-to-tankless conversion can reach $3,900–$6,000, while a full fuel conversion or major electrical project can exceed $10,000.
Is gas or electric tankless cheaper to install?
Electric is usually cheaper when the existing panel can support the unit because it needs no gas vent or fuel line. A whole-home electric model that needs new circuits or a service upgrade can cost as much as, or more than, a gas installation. Price the infrastructure before deciding on fuel.
Does replacing a storage tank with tankless save money?
It can reduce energy use and extend service life, yet the installation premium may take many years to recover. DOE's gas-tankless savings range depends heavily on daily hot-water use, and ENERGY STAR estimates about $95 per year for a typical family comparing certified gas tankless with standard gas storage. Run the payback calculation with your quote and local rates.
Does a tankless water heater qualify for a federal tax credit in 2026?
No property placed in service after December 31, 2025 qualifies for the former section 25C credit. Qualifying property placed in service by that date belongs to the 2025 tax year and follows the 2025 Form 5695 rules.
How long does a tankless water heater last?
ENERGY STAR lists about 20 years for tankless equipment, provided it receives the maintenance required by the manufacturer. Hard-water scale can reduce flow and shorten life, so include periodic flushing or professional service in your ownership budget.
Sources
Time-sensitive tax and rebate guidance:
- Internal Revenue Service, section 25C expiration FAQ.
- Internal Revenue Service, 2025 Form 5695 instructions.
- ENERGY STAR, natural-gas water-heater tax credit.
- UGI Utilities, gas tankless water-heater rebate.
- ENERGY STAR, Rebate Finder.
Bottom line
Use $1,400–$5,600 as a starting range for a standard whole-home installation, then move higher when the project adds gas-line, venting, electrical, relocation, or access work. The old federal tax credit is not available for property placed in service in 2026, so include only documented local or utility incentives. Get at least two itemized quotes, compare the model's GPM at your cold-water temperature, and compare the full project cost with a heat pump or storage alternative. Start with Watt Wallet's incentive finder before you finalize the budget.