Tankless Water Heater Install Cost 2026: $2,500–$5,500

Installing a whole-house gas tankless water heater in a US single-family house — replacing a tank in the same closet, basement, or garage, on a gas line that is already large enough, with a straightforward new vent, the old tank hauled away — often clusters around $2,500–$5,500. That is the typical tankless water heater installation cost, and the typical tankless water heater cost installed, for that gas job. It is also the whole house tankless water heater cost when one unit serves the house. The wider national spread, about $400–$8,500, covers a point-of-use electric unit at one sink in a lower-cost area at the low end and a whole-house gas conversion with a gas-line upsize, a difficult vent, and tight access at the high end. A panel upgrade for an electric unit, or a gas line run the length of the house, can clear that spread. These are typical planning ranges, not a survey and not a quote.

This page is a tankless water heater. A like-for-like tank swap, and a heat-pump water heater, are the water heater guide. A boiler that also heats the house is a different product. A point-of-use unit under one sink is on this page. It is a smaller scope than the whole-house band.

The carton price is not the job. A tankless unit at a home center can look like several hundred to a couple of thousand dollars. The bid is the vent, the gas pipe or the electric circuits, the permit, and the trip to haul the old tank out without flooding the floor. A 40- or 50-gallon tank is stored water. A tankless unit is a flow rate. Price the gallons per minute and the fuel you have, not a shelf tag.

The rows below are ways to read one job. They are not added together. The gas, electric, and point-of-use rows are different scopes. The gas row already includes a straightforward dedicated vent, a connection to a gas line that is already the right size, service valves, haul-away of the old tank, a condensate line to a nearby drain when the unit is condensing, and an ordinary permit. Use an add-on row only when that assumption fails. A panel that cannot carry an electric unit is the panel guide, not a second copy of the electric row.

Scope	Typical planning range
Whole-house gas, replacing a tank	$2,500–$5,500
Whole-house electric, service can carry it	$1,500–$3,500
Point-of-use electric, one fixture	$400–$1,200
Point-of-use gas, one fixture	$1,200–$2,800
Gas line upsizing	Often $500–$2,000 extra
Long or difficult vent	Often $400–$1,500 extra
Electrical circuits, panel has capacity	Included in the electric row
Panel or service that cannot take the load	Often $2,000–$4,200, on the panel guide
Condensate drain, no drain nearby	Often $150–$450 extra
Permit	Often $50–$300, already inside the installed rows
Old tank removal	Included; often $100–$300 if the bid leaves it out

Whole-house gas is the $2,500–$5,500 band. The low end is a condensing unit, a short plastic vent through a nearby wall, a gas line that does not have to grow, and an open mechanical room in a lower-cost area. The high end is a tighter closet, a short stainless vent, or a high-labor city, still without a new gas line the length of the house. This is the cost to convert to a tankless water heater when the house is already set up for it.

Whole-house electric is typically $1,500–$3,500 when a load calculation already passes and the panel has legal spaces for the new breakers. The unit can cost less than a gas unit. The circuits are the work. A 200-amp house with gas heat, a gas range, and room in the load calculation is the sort of service that can land in this row. A 100-amp house that already runs an electric range, a dryer, and central air usually cannot. That house is the panel row, often $2,000–$4,200 for a straightforward 100-amp to 200-amp upgrade on the electrical panel guide, and the heater is still its own price. Keep the two bids separate.

Gas vs electric tankless installation cost is those two rows. Gas is the typical band on this page because replacing a gas tank with one whole-house unit is the common job, and the vent and the gas connection are why it sits higher. Electric is lower only while the service can take it. Compare them on the same house. An electric quote that ignored the panel is not the cheaper bid.

Point-of-use electric, one fixture, is typically $400–$1,200. That is a small unit under a sink or at one lavatory, with a short water connection. The floor of the wider spread, near $400, is that easy unit in a lower-cost area. A unit sized for a shower sits toward $1,200 and can leave the row. Point-of-use gas is typically $1,200–$2,800, because even one fixture needs a gas connection and a vent. It is uncommon. Two point-of-use units are two installs. They are not a discount taken off the whole-house row.

Gas line upsizing is typically $500–$2,000 extra, and only when the existing pipe is too small. A tank often sits on a half-inch branch. A whole-house gas tankless unit often needs a larger pipe, commonly three-quarter inch, over the length the manufacturer’s chart allows. A short upsize in an open basement is the low end. A new run from the meter, across the house, is the high end and can leave $2,000. Stacked on the top of the gas row, that long run can clear the $8,500 top of the wider spread. The gas row assumes the line is already large enough. A bid that already upsized the pipe is one number, not the gas row plus this row.

A long or difficult vent is typically $400–$1,500 extra. A straightforward vent is already in the gas row: a short plastic run for a condensing unit, or a short stainless run for a non-condensing unit, to a wall or a roof the crew can reach. The add-on is a long metal vent, a chase through finished rooms, or a termination that means scaffolding. The old atmospheric flue from the tank, the B-vent a standard tank often uses, is the wrong vent for a tankless unit. Reusing it is not a savings.

Electrical circuits, when the panel has capacity and a legal space, are inside the electric whole-house row. A gas tankless unit needs power for the fan and the controls. That small circuit is inside the gas row. A whole-house electric unit is a different load: often more than one heavy 240-volt circuit, and a large share of the service. A single new 240-volt receptacle, the circuit on the 240-volt outlet guide, is not this heater. If the bid already includes the circuits, do not add that guide on top. If the panel cannot take the load, price the service on the panel guide.

A condensate drain to a nearby floor drain or laundry drain is inside the gas row for a condensing unit. When the condensate cannot fall to a drain, a pump and a longer line are typically $150–$450 extra. A neutralizer belongs on that line when the condensate would reach a septic system or the local code asks for one. The condensate is acidic. A non-condensing unit does not make it.

An ordinary permit is often $50–$300 and already sits inside the installed rows. Ask for it as its own line anyway. A price with no permit, in a city that requires one, is not comparable.

Old tank removal is included in the whole-house rows. If a bid leaves haul-away out, it is typically $100–$300. A tank full of water is a two-person lift and a truck. Confirm the bid says the old tank leaves.

What the range includes

The typical band assumes an existing single-family house, one whole-house gas tankless unit where the tank sits, on gas, with a gas line that is already the right size. It includes the unit, a straightforward dedicated vent, reconnection of the water lines, a condensate drain when the unit is condensing and a drain is nearby, service valves so the heat exchanger can be flushed, haul-away of the old tank, and a permit where the city requires one. A recirculation loop, a move to another room, and a panel upgrade are separate projects.

Size the unit in gallons per minute, not in the gallons the old tank held. A tankless unit heats water as it flows. The number that matters is how many gallons per minute it can raise to shower temperature from the water coming into your house. A lavatory is a small draw. A shower is the draw that sets the size. A modern shower head is often about 2 gallons a minute. Two showers at once is the usual whole-house question. A dishwasher or a washing machine on top of one shower is the next question. A point-of-use unit is sized for the one fixture it feeds, which is why it is the $400–$1,200 electric row or the $1,200–$2,800 gas row, not the whole-house band.

Incoming water temperature changes the flow. The same unit delivers fewer gallons per minute when the groundwater is cold, because the temperature rise is larger. Ask the bid for the gallons per minute at a winter incoming temperature for your area, not the largest number on the carton. A unit that is too small runs lukewarm when two fixtures open. A unit that is far larger than the fixtures does not fix a gas line that is too small, and it does not fix a shower head that flows more than the unit can heat.

Condensing and non-condensing are two gas machines. A non-condensing unit sends hotter exhaust out a stainless vent and does not make condensate. That vent cannot be the old flue from the tank. A condensing unit pulls more heat from the exhaust, so the vent can be plastic, and the unit makes condensate that has to reach a drain. Condensing is the common whole-house gas install, because a short plastic vent is simpler. Non-condensing can cost less as a unit and more as a metal vent. A short stainless run can still sit in the typical band. A long one is the $400–$1,500 add-on. Ask which type the bid is. The two prices are different scopes.

A tank is often replaced around 8 to 12 years, the planning age on the water heater guide. A tankless heat exchanger is often planned for a longer life, around 15 to 20 years, and that expectation holds only if the unit is descaled. It is a planning life, not a warranty you can spend. Hard water shortens the interval. Soft water lengthens it. Follow the schedule the manufacturer prints, often yearly where the water is hard.

Maintenance is a flush, not a new unit. Scale coats the heat exchanger, and the unit starts to overheat, rumble, or cut the flow. Isolation valves are what let someone circulate a descaling solution without cutting pipe. Those valves belong on the install. A plumber’s flush is typically $100–$300. Skipping it is how a unit that was supposed to outlast a tank fails in the same decade.

Payback versus a tank is slow, and it is general. A like-for-like tank swap is typically $1,400–$2,800 on the water heater guide. A whole-house gas tankless unit is typically $2,500–$5,500 here. The two bands meet when a straightforward tankless quote is set next to a gas tank at the top of the tank range. Otherwise the gap, before a gas-line upsize or a panel, is often about one to a few thousand dollars. A tankless unit does not keep a tank of water hot between draws, so a household that uses hot water in short bursts spends less on that standby. A household that runs long showers back to back spends most of its money heating water it actually uses, and the fuel difference shrinks. Divide the extra install cost by your own fuel difference if you want a personal payback. A brochure figure is not that number. In general the conversion pays for itself slowly, when it pays for itself at all, and a gas line or a panel upgrade can erase the fuel argument. People still choose the unit because the hot water does not run out, and because a tank on the floor can leak.

The floor of the national spread, near $400, is one easy point-of-use electric unit. The top, toward $8,500, is where a whole-house gas conversion, a gas-line upsize, a difficult vent, and tight access usually land together. A panel upgrade, or a gas line the length of the house, can clear that top. Treat a number above it as a different scope and ask which driver caused it.

None of the bands include a kitchen remodel, a bathroom remodel, a new furnace, a main sewer line, a whole-house repipe, or a heat-pump water heater. A tankless unit added while the kitchen walls are open is still this guide, and it often pulls in the panel guide as well. Weak hot water in a bath is not a reason to hide the heater inside the tile allowance. If the furnace and the old tank share a chimney, and a new furnace will no longer use that flue, the tankless vent is part of this job. An abandoned chimney is not a tankless vent. If water stains start at a vent flashing, price that leak on the roof guide before you blame the heater.

As a cross-check, not a bid: a whole-house gas unit in the same spot, on an adequate gas line, is the $2,500–$5,500 band. A whole-house electric unit on a service that can carry it is $1,500–$3,500. Adding a $500–$2,000 gas-line upsize to the gas band is how a conversion leaves the typical cluster and stays inside the wider spread, until the run is long enough to clear it. The planning numbers are before rebates. Ask what your utility still pays for a high-efficiency unit, and do not subtract a credit the bid assumed is gone.

What moves the price

Driver	How it changes the bid
Fuel	Whole-house gas is the typical band, $2,500–$5,500. Whole-house electric is typically $1,500–$3,500 when the service can carry it, and a panel project when it cannot.
Whole-house or point-of-use	One unit for the house is the gas or electric row. One fixture is $400–$1,200 electric or $1,200–$2,800 gas. Two point-of-use units are two installs.
Gallons per minute	A unit sized for one shower sits lower in the gas band. A unit sized for two showers at once, in a cold climate, sits toward the top. The winter incoming temperature is the test, not the carton peak.
Condensing or not	Condensing uses a plastic vent and needs a drain. Non-condensing uses stainless and has no condensate. A long metal vent is the $400–$1,500 add-on.
Gas line	An adequate line is inside the gas row. Upsizing is typically $500–$2,000 extra. A half-inch branch that fed a tank is the usual reason.
Vent path	A short new vent is inside the gas row. The old tank flue is not reusable. A long chase or a hard roof termination is the vent add-on.
Electrical	A gas unit’s control circuit is inside the gas row. Electric whole-house circuits are inside the electric row only when the panel has the amperage and the spaces. Otherwise it is the panel guide, often $2,000–$4,200.
Condensate, permit, haul-away	A nearby drain, an ordinary permit of $50–$300, and haul-away are inside the installed rows. A pumped drain is typically $150–$450. Haul-away left out of a bid is typically $100–$300.
Access and region	An open basement or garage in a lower-cost area sits toward the floor of the row. A second-floor closet, a crawl space, or a high-labor city sits toward the top and can leave it.

If the heater sits in a tight closet, say so. A gas unit needs the vent path and the clearance the manufacturer prints. A unit that cannot get that vent is the wrong product.

Very hard water does not forbid tankless. It shortens the descaling interval, and a softener is its own project. It is not a line on this table.

DIY or hire

Hire the installation. Gas piping, a new vent, and a new electric circuit are licensed work in most cities, and the permit is part of the job. Combustion venting is where a small mistake becomes carbon monoxide. A whole-house electric unit is a large 240-volt load landed in the panel. That is not a homeowner add-on.

A careful owner can sometimes flush a unit that already has isolation valves, with the descaling solution the manufacturer names. If the valves are not there, cutting into the water lines on a gas appliance to add them is a hire. Changing a temperature setting and keeping the inlet screen clear are ordinary owner tasks. They are not an installation.

Hire even more clearly when the job upsizes the gas line, moves the heater, runs a vent through a finished chase, or needs a panel upgrade. Those are the jobs where a mistake becomes a leak, a vent that dumps into the attic, or a breaker that will not stay on.

Repair or replace

Repair a tankless unit when it is under about 10 to 12 years, it has been descaled, and one part failed: an ignitor, a fan, a sensor, or scale that a flush will clear. A flush is typically $100–$300. Ask for that price next to a replacement price. A repair that is a large fraction of a new unit, on a heat exchanger that is already scaled shut or cracked, is usually the wrong purchase.

Replace the tankless unit when the heat exchanger has failed, the unit is past the long end of a 15- to 20-year planning life, or the same error codes come back after a flush and a new sensor. Also replace the tank, in the sense of leaving it behind, when the tank is leaking from the vessel or is past about 8 to 12 years and the gas line or the panel can take a tankless unit. If the tank wall is dry and the tank is young, repair the tank. A new tankless unit does not fix a young tank’s failed thermostat.

No hot water is not automatically a dead unit. A tripped breaker, a failed ignitor, a gas valve that will not open, or a heat exchanger full of scale can be a repair. A unit that runs cold only when two showers are on is often undersized, or the incoming water is colder than the bid assumed. That can be a different unit. It can also be a fixture that flows too much. Check the shower head before you buy a larger heater.

How to use this number

Ask for a written price that names the gallons per minute at a stated temperature rise, gas or electric, condensing or non-condensing, whether the heater stays in the same spot, the vent material and the path, whether the gas line is reused or upsized, who hauls away the old tank, whether service valves are included, and whether a permit is pulled. Compare a whole-house gas replacement on an adequate gas line with $2,500–$5,500. Compare whole-house electric, on a service that can carry it, with $1,500–$3,500. Compare one point-of-use fixture with $400–$1,200 electric or $1,200–$2,800 gas. Keep a gas-line upsize, a long vent, a pumped condensate drain, a panel upgrade, and a tank swap as their own lines.

A very low bid on a whole-house gas unit is a reason to ask whether the vent, the permit, and haul-away are included, not a reason to celebrate. A tankless quote near a tank price usually means the gas line and the vent were assumed to be adequate. Confirm that in writing. A high bid should point at a gas-line upsize, a stainless vent, access, or a panel. Two or three local bids on the same fuel and the same location are the number that matters. How this site sets the band is explained on the methodology page.