How much does a tankless water heater cost to install in Virginia?

A tankless installation can cost 1½ to 2 times what a tank heater's does, by a federal yardstick built on 2012 costs.^[1] The hardware itself is generally more expensive than for tank-type heaters,^[1] but the heater is only part of the bill. What moves the price is how much of the house has to change around it: the gas line, the vent, a drain, an outlet and sometimes the heater's location. The way to a real number is three written quotes for the same, clearly described job.

How it compares with a tank heater

The Department of Energy's Building America guide gives a rough yardstick: the initial installed cost of a tankless water heater can be 1½–2 times as much as that of a tank-type water heater.^[1] Treat that as dated: the average industry costs in the guide come from an analysis from 2012,^[1] and the guide also says: "Tankless water heater costs have fallen as the systems have become more popular."^[1] It adds that both equipment and installation costs vary, depending on locale,^[1] and that installation can cost less than for a gas tank heater when the job avoids building a flue or chimney.^[1]

For the cost of replacing a tank heater instead, see what a water heater replacement costs in Virginia.

What drives the price of a tankless installation

The gas line. The same guide says: "Most tankless gas water heaters require a minimum ¾-inch gas line from the street and code may require it, while 1/2 –inch line is typically sufficient for tank water heaters and other gas appliances."^[1] Depending on the other gas appliances, the main line from the meter and the branch lines may both need to be larger than they would for a tank heater.^[1] Noritz, which does make models for ½-inch lines, still advises: "Tankless water heaters require more BTU demand than regular storage tanks therefore it is recommended that you contact a qualified plumber to see if your gas line needs to be changed."^[6] Our answer on what running a gas line costs covers that part.

Venting. "If you are replacing an existing tank water heater you will likely need to install a new vent pipe."^[1] Gas tankless units are often vented sideways through a wall, so an old chimney that served the tank may need to be sealed off, and if the old heater shared a flue with the furnace, the installer should test the furnace's draft after the water heater comes off it.^[1]

Location. "The ideal location for a tankless water heater is on or near an outside wall."^[1] If your tank sits in the middle of a basement, moving the heater means new water and gas piping as well as the vent.

Condensing or not. Condensing models use less gas, but these condensing models need venting through a vertical PVC pipe and a condensate drain.^[3] The Building America guide adds that a neutralizing system is recommended because the condensate is slightly acidic and can damage drain pipes over time.^[1]

Electrical work. Even natural gas units need a 120-volt outlet for their controls, sensors and electric spark ignition,^[1] so a gas tank location with no outlet needs one added. Electric tankless models are a much bigger electrical job. A. O. Smith states: "Electric tankless heaters require between 100 and 140 amps, depending on the model."^[5] It adds that switching to one may mean upgrading the electrical service panel.^[5]

Service valves. The Building America guide recommends fitting isolation ("flush kit") valves when the heater goes in, so it can be cut off from the rest of the house's plumbing and its heat exchanger descaled later. "Adding these valves during installation is a small cost"^[1] that pays back at every service. See how often a tankless heater needs descaling.

Size and number of units. A bigger household running several fixtures at once needs a larger unit. If you tend to use hot water in several places at the same time, you may need two or more tankless water heaters to keep up.^[4]

Timing. ENERGY STAR advises planning ahead, because your installer may need time to order the right model, and the job may take longer than a standard water heater installation.^[2] An emergency replacement on the day the old tank fails leaves less room to compare quotes.

The permit

Virginia's building code requires a permit before work on equipment the code regulates and on fuel supply systems, and its exemption for replacing appliances in houses does not cover equipment fueled by gas or oil.^[7] So a gas or propane tankless installation needs a permit; our water heater permit answer explains the rest.

Each city and county sets its own fee. As one dated example, Spotsylvania County's residential mechanical permit packet, updated August 2025, listed a water heater replacement permit at $147.00 when we checked on October 26, 2026: $100.00 for the trade, a 2% building surcharge and a $45 processing fee.^[8] Your locality's fee may differ, and a job that also adds gas piping or a circuit may need more than one trade permit. Confirm the quote includes every permit and inspection.

Running cost and lifespan

The installed price is paid once; the energy bill runs for decades. The Department of Energy's Energy Saver guide says that for homes that use 41 gallons or less of hot water a day, gas on-demand heaters can be 24% to 34% more energy efficient than conventional storage tank heaters, and 8% to 14% more efficient in homes that use around 86 gallons a day.^[4] It also says: "Most storage water heaters last 10-15 years, while tankless water heaters can last more than 20 years."^[4] Whether that adds up for your home is the question in is a tankless water heater worth it.

On incentives, the IRS says of the federal Energy Efficient Home Improvement Credit: "You can claim the credit for improvements made through December 31, 2025."^[9] Check current IRS guidance or ask a tax professional before counting on a credit for a later installation, and ask your gas or electric utility what rebates it offers now.

What to ask for in a written quote

ENERGY STAR notes that you will need an installer to visit and price the job, and that the installer should confirm the right GPM size for your home, whether your existing gas line is big enough, whether electricity is available near the heater, and how the combustion gases will be vented.^[2] Virginia's Board for Contractors adds: "It is advisable to get at least three written bids or estimates using identical plans and specifications so you can compare prices and contractors."^[10] Make each bid name:

• the make, model, GPM rating at your winter temperature rise, and efficiency rating;
• the gas line work, with the pipe size and length;
• the vent route, the condensate drain and neutralizer if it is a condensing unit;
• any electrical work, and who holds that licence;
• isolation valves for descaling, and removal of the old heater;
• the permits and inspections;
• the heat exchanger warranty and the installer's labour warranty.

Keep the deposit modest. The Board's rule of thumb is a deposit of no more than 10% of the total price or $1,000, whichever is less,^[10] and it reminds homeowners: "Virginia law requires all licensed contractors to provide a written contract for residential work."^[10]

When to call a licensed pro

Every part of this job is licensed work in Virginia. Under the Code, Class C contractors take on single jobs over $1,000 but less than $30,000, and the Board for Contractors requires a master tradesman licence as a condition of licensing plumbing and HVAC contractors.^[11] The gas piping is not a job for a fitter without that certification either: the Code's definition of a natural gas fitter provider excludes new installation of gas piping for hot water heaters, which requires HVAC or plumbing certification.^[12] Check the contractor's licence before you sign.

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