Tankless Water Heater Installation Cost in 2026: Prices by Fuel Type and Scenario

What you will actually pay

A whole-house tankless water heater costs $2,800 on national average installed, with most homeowners paying between $1,400 and $5,600 for the unit plus professional installation. Fixr puts the 2026 national average at $2,811 for an installed 150,000 BTU gas model with an average range of $2,500 to $4,500, while Angi reports an average professional installation of $2,630.

The wide band exists because fuel type and install scenario move the price more than any other factor. An electric unit in a home with an adequate panel sits near the bottom of the range; a gas unit that needs a bigger gas line, new venting, and a tank haul-away sits near the top. HomeGuide's 2026 installed band of $1,400 to $5,600 brackets both extremes.

Sources: HomeGuide: How Much Does a Tankless Water Heater Cost? (2026), Fixr: Tankless Water Heater Installation Cost (Fixr, 2026), Angi: How to Hire a Tankless Water Heater Installation Pro (Angi, 2026)

Cost by fuel type: gas vs electric

Gas tankless units cost $2,100 to $5,600 installed according to HomeGuide, with the unit alone at $1,500 to $2,600. Gas carries higher flow rates, which matters when two showers and a dishwasher run at once, and it costs less to run in most regions where natural gas is cheaper per delivered BTU than electricity. Propane units land at $1,600 to $4,500 installed.

Electric tankless units cost $1,400 to $3,000 installed, with units at $600 to $1,000. They are cheaper and simpler for point-of-use jobs, but a whole-house electric unit commonly draws 24 to 36 kW and may need multiple double-pole breakers, heavy-gauge wiring, and a 200-amp service. Region Home Services notes that a $500 to $2,000 panel upgrade can erase the equipment savings, so price the electrical work before assuming electric is cheaper.

Sources: HomeGuide: How Much Does a Tankless Water Heater Cost? (2026), Region Home Services: Cost of Tankless Water Heater Installation in 2026 (Region Home Services)

Your install scenario matters more than the brand

Three scenarios cover nearly every residential tankless project, and identifying yours narrows the estimate more than any other single question. A direct swap, tankless replacing tankless with the same fuel and location, runs $1,200 to $2,800 because the gas line, venting, and mounting are reused. A conversion from a storage tank with the same fuel runs $2,000 to $4,500, adding wall mounting, new venting, a gas line sizing check, condensate routing, and tank removal.

A full conversion, meaning a fuel change, gas line upsizing, or electrical panel work, runs $2,500 to $7,000 or more. The single most common surprise is gas capacity: a storage tank burns about 40,000 BTU on a half-inch line, while a whole-house tankless unit demands 150,000 to 199,000 BTU and usually needs three-quarter-inch pipe back to the meter. Local Service Calculator estimates the gas line work alone adds around 35% to the job, so ask whether the line has been sized before accepting any quote.

Sources: Region Home Services: Cost of Tankless Water Heater Installation in 2026 (Region Home Services), Local Service Calculator: Tankless Water Heater Installation Cost Calculator 2026 (Local Service Calculator), iamhome.app: Water Heater Replacement Cost: The True 2026 Price Guide

What size tankless unit do you need?

Tankless units are sized by flow rate, not by gallons. Two numbers decide the size: your peak simultaneous demand, measured in gallons per minute (GPM), and the temperature rise your climate demands.

Start with peak demand. Add the flow rates of the fixtures that could run at the same time on a busy morning: a standard shower head draws 2.0 to 2.5 GPM, a low-flow shower head 1.0 to 1.5 GPM, a bathroom faucet 1.0 to 1.5 GPM, a kitchen faucet 1.5 to 2.2 GPM, a dishwasher 1.5 to 2.5 GPM, a washing machine 2.0 to 3.0 GPM, and a bathtub fill 4.0 to 6.0 GPM.

Example: one shower at 2.5 GPM plus a dishwasher at 2.0 GPM plus a bathroom faucet at 1.0 GPM gives a peak demand of 5.5 GPM. That number is the target when you compare units. As a rough rule, 1 to 2 fixtures running together needs about 3.5 GPM of capacity, 2 to 3 fixtures about 5 GPM, and 3 to 4 fixtures about 7 GPM.

Then check temperature rise: the difference between your target output (usually 120F) and your incoming groundwater temperature. In the South the rise can be around 35F; in northern states it can reach 65F in winter. A unit's rated GPM drops as the rise increases, so always check the manufacturer's flow rating at your rise, not the headline number. If you are between sizes, size up slightly: an undersized unit gives lukewarm water the moment two fixtures run at once.

How sizing moves the price: a higher GPM rating means a higher BTU burner, a larger and pricier unit, and often more gas line and venting work. That is why two homes can buy the same brand and pay very different installed totals. Your install scenario still moves the final number more than the unit size alone.

Sources: Rinnai: Rinnai Water Heater Sizing Guides, Emergency Plumbing: Tankless Water Heater Sizing: How Many GPM Do You Need?

What the major brands cost (unit only)

Unit prices cluster in a narrower band than installed totals. Typical 2026 unit-only ranges for whole-house gas models: Rinnai $1,100 to $2,600, Navien $1,000 to $2,200, Rheem $800 to $2,000, Noritz $900 to $2,400. Maximum flow ratings run about 9.5 GPM (Rheem) to 11.2 GPM (Navien), with Rinnai and Noritz near 11 GPM. Heat exchanger warranties are 15 years on Rinnai and Navien and 12 years on Rheem and Noritz (Noritz extends to 25 years on its EZ series).

Two things matter more than the brand badge. First, the unit is roughly a third to half of the installed total; your scenario, swap, conversion, or full conversion, moves the final number more than the brand choice. Second, the Noritz EZ series is designed for tank replacements and can sometimes reuse the old venting path and gas line, which trims the install side. Brand prices move with retail promotions, so confirm against current listings before budgeting.

Sources: TanklessWaterHeaterInstallCost.com: Top Tankless Water Heater Brands Compared (2026), Repipe Solutions: Navien vs Rinnai vs Rheem Tankless Water Heater Comparison (Houston)

Labor, upgrades, permits, and the line items quotes hide

The unit itself is only 30% to 50% of the total, which is why the price on the box tells you almost nothing about the final bill. HomeGuide breaks installation into labor at $600 to $2,500 for 3 to 10 hours, supplies at $150 to $300, and permits at $50 to $200. Region Home Services prices the full line-item stack: venting $300 to $800, gas line upsizing $400 to $2,000, old tank removal $50 to $500, condensate drain or pump $100 to $300, and an expansion tank $50 to $350 where code requires one.

Two costs catch buyers off guard. First, venting cannot be reused: a non-condensing unit exhausts too hot for plastic and needs stainless steel, while a condensing unit vents in PVC straight through an exterior wall, so either way it is a new vent route. Second, the federal tax picture changed: the Section 25C credit ended for property placed in service after December 31, 2025, so a quote that still shows a federal credit as an offset is working from outdated guidance. State energy offices and utilities still offer rebates, typically $200 to $1,000, but you have to check locally.

Sources: HomeGuide: How Much Does a Tankless Water Heater Cost? (2026), Region Home Services: Cost of Tankless Water Heater Installation in 2026 (Region Home Services), iamhome.app: Water Heater Replacement Cost: The True 2026 Price Guide

Tankless vs a standard tank: the honest payback math

A standard tank water heater costs $600 to $3,100 installed, roughly half the tankless band, and lasts 8 to 12 years against 15 to 20 for tankless. Tankless units use about 25% to 30% less gas because nothing is kept hot around the clock, which Local Service Calculator translates to $80 to $180 a year for a typical household. Against a job that costs roughly $1,800 more than putting another tank in, that is a ten to twenty year payback on a unit that lasts about twenty years. Our water heater installation cost guide covers conventional tank pricing.

So the energy saving is real but secondary. The reasons that actually justify tankless are that it never runs out of hot water, it lasts about twice as long, it gives back the floor space a tank occupies, and it cannot flood a utility room. Tankless makes the most financial sense with high simultaneous hot water demand, existing infrastructure that already supports it, and an owner planning to stay past the break-even point around year eight to ten. If you are selling within five years or the conversion quote lands at the top of the range, another tank is the better call. Scale buildup is the main killer of tankless units; our water softener installation cost guide prices the protection.

Sources: HomeGuide: How Much Does a Tankless Water Heater Cost? (2026), Local Service Calculator: Tankless Water Heater Installation Cost Calculator 2026 (Local Service Calculator), Region Home Services: Cost of Tankless Water Heater Installation in 2026 (Region Home Services)

Worked example and limitations

Take a two-bathroom home converting from a 50-gallon gas tank to a condensing gas tankless unit. The unit runs about $1,300 to $1,900, labor 6 to 10 hours, new PVC venting through an exterior wall, a gas line upsizing from the meter, a permit and inspection, and haul-away of the old tank. Local Service Calculator's 2026 model prices exactly this job at $4,500 typical, within a $3,675 to $5,575 band, with the gas line work as the single biggest variable.

Limitations: this is a MEDIUM-confidence national planning range, not a quote. Labor rates vary widely by metro, and your scenario (swap, conversion, or full conversion) moves the price more than the brand. The range covers a professionally installed whole-house unit; single-point units ($150 to $300 per unit) and solar configurations (up to about $6,700) sit outside it. It excludes operating energy costs, annual descaling at $100 to $250, and any structural or drywall repair beyond the heater location. Always get at least three itemized estimates from licensed pros and confirm the gas line sizing, vent route, permit, and disposal are each named in the quote.

Sources: Local Service Calculator: Tankless Water Heater Installation Cost Calculator 2026 (Local Service Calculator), Fixr: Tankless Water Heater Installation Cost (Fixr, 2026), Angi: How to Hire a Tankless Water Heater Installation Pro (Angi, 2026)