Yes, you can do it yourself – learning how to install an electric tankless water heater is a big project but possible for a handy homeowner. You’ll need to handle electrical and plumbing work, so be ready for both.
I’ve helped friends with this job a few times. It saves a lot of money compared to hiring a pro.
The key is planning each step before you start. You don’t want to cut off your hot water and then get stuck.
This guide walks you through the whole process. I’ll share the tips that make it go smooth.
What You Need to Know First
Before you buy anything, check your home’s setup. This is the most important step.
You need enough electrical power. Most units need a lot of amps, more than an old tank heater.
Look at your main electrical panel. You might need to add new breakers or even upgrade the panel itself.
Think about your water use too. How many showers or sinks run hot water at the same time?
Pick a unit that can keep up. A small one won’t work for a big family.
You also need the right tools. I’ll list everything you need later in the guide.
Gathering Your Tools and Parts
Don’t start the job without the right stuff. A trip to the store mid-project is a pain.
You’ll need basic plumbing tools. Get pipe wrenches, Teflon tape, and a tubing cutter.
For the electrical side, you need wire strippers and a voltage tester. Safety glasses are a must.
Buy the right wire and conduit. The manual for your heater will tell you the exact size.
Get shut-off valves and the right pipe fittings. Measure your old pipes so you get the correct size.
Have a bucket and towels ready for water. There’s always a little spill when you disconnect the old lines.
Turning Off Power and Water
Safety comes first, every single time. You are dealing with water and high voltage electricity.
Go to your main electrical panel. Find the breaker for your old water heater and turn it off.
Use your voltage tester to double-check. Make sure the power is really off at the heater.
Next, find your main water shut-off valve. Turn it to stop water flow to the whole house.
Open a faucet on the lowest floor. This lets pressure drain from the pipes.
Connect a hose to the drain valve on your old tank heater. Run the hose to a floor drain or outside.
Open the drain valve and let the tank empty. This can take a while for a big tank.
Removing the Old Water Heater
Now it’s time to take out the old unit. This part is mostly plumbing work.
Disconnect the water lines from the old heater. Use your pipe wrenches carefully.
Have that bucket ready under the connections. A little water will still come out.
Disconnect the electrical wires next. Remember, you already turned the power off at the breaker.
Double-check with your voltage tester again. Then remove the wires from the old unit.
The old tank will be heavy, even when empty. Get a friend to help you move it.
Take it out of the space. Now you have a clean area to learn how to install an electric tankless water heater.
Planning the New Installation Location
Where you put the new unit matters a lot. Think about access and safety.
Most tankless heaters mount on a wall. Pick a spot with strong studs to hold the weight.
Leave space around it for air flow. The unit needs room to breathe so it doesn’t overheat.
Check the manual for clearances. It will say how much space you need on each side.
Make sure you can reach the water connections easily. You don’t want pipes hidden behind the unit.
Think about future service too. Someone might need to work on it later.
Mark the spot on the wall with a pencil. Use a level to make sure your marks are straight.
Running New Electrical Wiring
This is the hardest part for most DIYers. The electrical needs are big for a tankless system.
You will likely need to run new wire from your main panel. This is heavy-gauge cable.
According to OSHA, electrical work is a top cause of home project injuries. Be very careful.
Install a new circuit breaker in your panel. Make sure it matches the amperage your new heater needs.
Run the cable through conduit to the heater location. Follow all local electrical codes for this.
Leave extra wire at the heater end. You’ll need it to make the connections inside the unit.
When you learn how to install an electric tankless water heater, getting the wiring right is key. A mistake here is dangerous.
Mounting the New Heater Unit
Now you can put the new heater on the wall. This part feels good because you see progress.
Hold the mounting bracket against your marks. Drill pilot holes into the wall studs.
Use the screws that came with the heater. They are the right size and strength for the job.
Lift the heater onto the bracket. It’s lighter than the old tank but still awkward.
Get a friend to help you lift and hook it on. Make sure it sits level on the bracket.
Secure it with any extra screws or clips. You don’t want it to shake or fall later.
Take a step back and look at it. The unit should be solid and straight on the wall.
Connecting the Water Lines
Time to hook up the plumbing. This connects your new heater to your home’s hot water.
Install new shut-off valves on the cold water inlet and hot water outlet. This lets you turn off water to the heater later.
Use pipe dope or Teflon tape on all threaded connections. This stops leaks before they start.
Connect the cold water supply line to the inlet side. The inlet is usually marked with a blue ring or tag.
Connect the hot water line to the outlet side. This side often has a red ring or tag.
Use flexible braided lines if your pipes don’t line up perfectly. They make the connection much easier.
Leave the connections loose for now. You will tighten them in the next step.
Making the Final Electrical Connections
Go back to the electrical work. This is the last big wiring task.
Open the electrical cover on the heater. You’ll see terminals for the wires.
Strip the ends of your new cable. Follow the length guide in the manual.
Connect the wires to the correct terminals. The manual has a diagram for this.
Usually, black and red are the hot wires. White is neutral, and green or bare is ground.
Tighten the terminal screws firmly. A loose connection can cause heat and fire.
Carefully tuck the wires into the unit and replace the cover. Don’t pinch any wires.
Turning Everything On and Testing
The moment of truth is here. You get to see if your work paid off.
First, close the drain valve on your old tank location if it’s still open.
Slowly turn your main water supply back on. Listen for leaks at the new connections.
Go to the new heater and open its hot and cold shut-off valves. Water will now fill the unit.
Open a hot water faucet in your house. Let it run for a few minutes to clear air from the lines.
Now, go to your electrical panel. Turn on the new breaker you installed for the heater.
You should hear a small hum or see lights on the heater’s display. It’s now heating water.
Learning how to install an electric tankless water heater ends with this test. Check for hot water at your faucet.
Common Mistakes to Avoid
I’ve seen people mess up a few ways. Don’t make these same errors.
The biggest mistake is not getting enough power. Your heater won’t work right if it’s under-powered.
Another error is bad venting or air flow. The unit needs cool air to work well and last long.
Forgetting the expansion tank is a common plumbing slip. Tank systems need this to handle pressure changes.
According to Energy.gov, proper sizing is critical for efficiency. A unit that’s too small runs constantly.
Not using dielectric unions can cause corrosion. These special fittings stop different metals from reacting.
Rushing the electrical connections is dangerous. Take your time and do it right the first time.
When you learn how to install an electric tankless water heater, avoid these pitfalls. They cost time and money to fix.
Maintenance Tips for Long Life
Your new heater needs a little care. It’s easier than maintaining an old tank.
Check the inlet filter every few months. It catches sediment from your water pipes.
Descale the unit once a year if you have hard water. Mineral buildup hurts performance.
Listen for strange noises. A high-pitched whine can mean there’s scale inside the heat exchanger.
Look at the error codes on the display. The manual explains what each one means.
Keep the area around heater clean and clear. Don’t store boxes or clothes near it.
Test the temperature setting now and then. Make sure it’s not set too high for safety.
When to Call a Professional
Some parts of this job might be too much. It’s okay to get help.
If your electrical panel is already full, you need a pro. Upgrading a service panel is complex.
Call a plumber if your pipes are old and corroded. They might break when you try to disconnect them.
If you turn everything on and get no hot water, get help. An electrician can find the wiring fault.
The National Fire Protection Association says faulty wiring causes many home fires. Don’t guess with electricity.
If you see water leaking from a connection you can’t stop, call someone. A small leak can cause big damage.
Learning how to install an electric tankless water heater is great, but know your limits. Safety always comes first.
Frequently Asked Questions
How hard is it to install an electric tankless water heater?
It’s a medium to hard DIY project. You need good plumbing and electrical skills. If you’ve done both before, you can probably handle it.
Do I need a permit to install a tankless water heater?
Most areas require a permit for this work. Check with your local building department. The permit makes sure the installation is safe and up to code.
How much does it cost to install an electric tankless water heater?
The unit itself costs $500 to $1500. If you do it yourself, you save on labor. Professional installation can add $1000 to $2000 to the total price.
Can I install a tankless water heater myself?
Yes, a handy homeowner can learn how to install an electric tankless water heater. Just be ready for the electrical demands. It’s not a simple swap like a light fixture.
How long does installation take?
For a first-timer, plan a full weekend. It might take 8 to 12 hours total. Having a helper can cut that time down a lot.
What size breaker do I need?
It depends on your unit’s power needs. Common sizes are 40-amp, 60-amp, or even 100-amp double-pole breakers. Always check the manufacturer’s specifications for your model.
Conclusion
So, should you try to install it yourself? If you’re comfortable with tools and careful, yes.
Learning how to install an electric tankless water heater saves you a lot of cash. It also gives you the pride of a job done well.
Take it step by step. Don’t rush the planning or the safety checks. Your family needs hot water that’s also safe.
Now you know the whole process. You can decide if it’s a project for you or a pro.