A plumber is usually the best person to install a tankless water heater. It's a complex process that requires multiple skills, so you'll want to choose an experienced plumber who knows the local building codes and permits needed for the project. 

In most states, plumbers need to be licensed. Check your state’s requirements, and then ask your plumber which licenses and qualifications they have. Professional plumbers should share this information and provide proof of their insurance.

Getting multiple quotes before choosing a contractor is always a good idea to avoid being overcharged. Asking for recommendations and reading reviews about various plumbers will also help you understand the quality of their work. 

Lastly, make sure your plumber has experience with tankless water heaters. Ask them plenty of questions and read their customer reviews to gauge their expertise.

For more tips, visit Thumbtack’s Smart Hiring page. 

The national average cost to install a tankless water heater is approximately $1,225,* according to Thumbtack data. However, installation prices range from around $1,870 to $2,310.*

There are various factors that may influence how much the project will cost, including:

• The brand of water heater

• Gas vs. electric (electric tankless water heaters are typically less expensive to install than gas tankless water heaters)

• Cost of labor in your area

• Size of the unit you plan to install

• Cost to make any gas, electrical and plumbing changes

*Data on file at Thumbtack. For a personalized cost estimate, request a quote from a professional.

Here are some reasons you might want to consider installing a tankless water heater instead of a storage water heater:

• Potential tax savings: You may be able to claim a tax credit if you install an energy-efficient tankless water heater. Visit the IRS website for the most up-to-date information.

• Lower energy use: Tankless water heaters only heat water as needed, which typically makes them more efficient than traditional storage water heaters, according to the Department of Energy.

• Savings on utility bills: The energy efficiency of tankless water heaters may also lead to lower utility bills over time, according to the Department of Energy.

• No more running out of hot water: Technically, tankless water heaters don't run out of hot water. However, excessive use or unusually high demand may lead to colder or fluctuating water temperatures.

• They take up less space: Compact and mounted on the wall, tankless water heaters use less space than bulky traditional tanks.

• They last longer: With proper maintenance, a tankless water heater typically lasts longer than its counterpart, according to the Department of Energy.

• Less chance of water damage: Tankless water heaters don’t typically leak as much as storage water heaters, reducing the risk of water damage. 

Although the installation process will vary depending on your project’s unique details, the plumber will typically start with:

• Securing the necessary permits: Ask your plumber how long it might take to obtain permits for your project.

• Making gas line upgrades: If necessary, your pro might advise you on any upgrades that are needed to your gas line before they begin. 

• Picking a location: Your pro may work with you to choose the best location for your tankless heater.

• Selecting a tankless water heater: Your pro might offer advice on which brand, type and size water heater to choose. 

The plumber may need to reroute pipes or drain your old water heater when removing it. However, most of the dust and tools should stay confined to the installation site, leaving the rest of your home clean and livable.

Also, keep in mind that some utilities may need to be shut off during installation.

Installing a tankless water heater can take anywhere from a few hours to two days.

The location of the water heater has a large impact on the project's timeframe. If plumbing, gas and electrical lines are close by, the project is generally quicker. But if new lines need to be laid, it may be a longer time frame.

Here are some general timelines to expect:

• Basic tankless heater replacement: Two to four hours

• New installation (no existing tankless unit): Four to eight hours 

• Complex installation: One to two days (or sometimes longer) 

Remember: The timeline for your project will vary depending on many factors. Always ask your pro to provide an estimate.

Installing a tankless water heater is a complicated task that often requires advanced knowledge in plumbing, electrical work and gas installations. It's usually best to hire a licensed plumber, as an incorrect installation can be dangerous and may even cause fires, gas leaks or explosions. 

Hiring a plumber can help ensure the job is done safely, correctly and efficiently. Although professional installation may cost more than DIY, it will likely save you time, reduce risks and prevent costly mistakes in the long run.

Also, tankless water heater installation typically requires a variety of tools, including wrenches, drills and bits, a level, mounting bracket and screws, pipe cutters and more. If you don’t have these tools on hand, you’ll need to consider the cost of buying or renting them.

Even if you feel confident in your abilities and want to do your own installation, you’ll need to ensure you follow your local electrical and plumbing codes — and you might need to obtain the appropriate permits.