How to Install a Tankless Water Heater

Installing a tankless water heater is a complex process that requires a lot of hard work and patience. Due to the immense number of benefits of tankless heating units many prefer to replace their old storage water heaters with the latest tankless ones.

If you have also purchased one now this question might pop up in mind how to install a tankless water heater. The two types of tankless water heaters are based on the source of energy.

The electric-powered ones are comparatively easier to install than the gas ones. This is cause for the gas ones the user needs to have proper connections, combustion gases exit valve, and safety measures.

Installing a Tankless Water Heater

There are different types of tankless water heaters available on the market that you can get. The gas and electric tankless water heaters installation processes are a bit similar but still have minor differences. Below we have described in detail the methods of installing the tankless water heaters.

How to Install an Electric Tankless Water Heater

how to install an electric tankless water heater

Tankless water heaters heat water on demand. It means water starts heating only when the faucet is turned on. As the user turns on the faucet water starts running through the tap. This water then reaches the electric heating element which raises the temperature of the water.

The heated water is then supplied out of the faucet. To have an efficiently working electric tankless water heater the electric connections should be done vigilantly. The job can be done by a professional plumber. But what if you want to install your unit yourself.

It’s surely possible but for you to be able to do so you need to know some basic steps. This article aims at enlisting the main points the user should be aware of while self water heater installation. This can make the process of installation easy for the buyer. Moreover, this reduces the chances of installation defects.

Electric Supply

Is your house already electric wired? Installing an electric appliance becomes easy when the house is already fully electric wired. These appliances demand a large electric supply so make sure the unit gets the needed electric supply to function effectively. To install such a unit you need to have bigger brakes and wires or else you will get lukewarm water.

To know whether your present electric supply will be sufficient for your water heating unit can be found by looking at the breaker box. If you are not able to decipher whether the current electric supply will work for your home or not try contacting your electrician.

Water Pressure

The water heater needs a certain level of water pressure to function. The required water pressure for most water heating units is 150 psi. If your water pressure is higher than this then install a pressure-reducing valve. If your water supply has a lower water pressure then this water won’t heat up as required.

Safety Permit

In some parts of the world, you have to get a safety permit before installing a unit. This includes an inspection of your place to look for any safety hazards.

A plumbing inspector will come to look for the installation work. They need to assure the connections are proper for the efficient working of the unit and won’t cause any safety issues to other nearby residents.

Location of Installation

Look for the right place to install your water heating unit. Try installing the unit at a location where you will need the warm water supply often near the dishwashing faucet or the laundry tap. As the electric water heaters don’t need venting and they don’t have a storage tank so you can place such a unit in any corner of your bathroom.

This is good news for those who have a small bathroom and installing a new unit will cause suffocation. With such a unit you won’t worry about space and can install the appliance in any corner.

However, beware not to install the unit anywhere close to the water tap so water won’t splash on it. Avoid places that are damp and have excessive moisture or humidity. If any of the above scenarios happens it can lead to unit damage.

Tools Needed for Installation of Tankless Water Heater

The tools needed for DIY unit installation are

  • Drill
  • Wrench
  • Flathead screwdriver
  • Measuring tape
  • Pipe cutter
  • Marker
  • Supplies
  • Piping ½ “
  • Valves
  • Insulation
  • Tape
  • Recirculation pump
  • Sandpaper

Installation Steps

Please note that improper installation can lead to voiding the warranty. The self-installation of an electric water heating unit is a complex task. If you fear you will not be able to do the task then take help from a professional electrician. Trying to save a few bucks can result in damaging the unit.

  • Start by disconnecting all power and water supply to your home.
  • Remove the front cover of the unit.
  • Mount the unit on the valve. Use the screws and anchors included in the package.
  • Now make the cold and warm water connections using stainless steel pipes. Use copper tubing for high-temperature appliances.
  • Some water heating units have a filter at the cold water inlet. This filter needs to be cleaned once a month. For easy maintenance, the cold water connections should be easier to remove.
  • A shutoff valve installed before and after the heater helps cut off the water supply whenever there is a need for cleaning. Place a pressure reduction valve on the cold water inlet in case your water pressure is higher than required.
  • Open all taps connected to the water heating unit to allow any air to escape that might be trapped in the pipes. Check for any possible leakage out of the pipes. Now close all the taps.
  • Using the manual make electric connections between the water heater and the electric panel. Larger units will need more circuits and a thicker wire. Check each electrical wire to the needed length and make sure you connect it to the right slot.
  • Recheck all the electric connections to make sure you have not done any mistakes.
  • Replace the front cover and turn on the circuit breaker.
  • Now configure your electric water heater to the required setting.
  • Open a warm water outlet to check if you have done the job right.

How to Install a Gas Tankless Water Heater

how to install a gas tankless water heater

Gas tankless water heaters need proper venting of the combustion gases. The units with sealed combustion can be installed in any available space. Make sure that you get the safety permit that ensures the unit won’t cause any hazard for others nearby. Once you are ready with all tools and supplies the steps are listed next

Proper Gas Connection

Gas tankless water heaters heat water on demand. The water is not stored in a tank. This minimizes energy loss. The gas-supplied units need a proper gas connection, combustion air, and vent system. In the long run, these units have a low running cost and are more useful but the installation cost is pretty high. For the unit’s efficient performance, you might need to upgrade your gas line.

Installing a tank-less gas water heater without any prior experience can be pretty dangerous and is not advised at all. Take help from a professional plumber for a seamless installation of the unit. Gas tankless water heaters need a higher water supply than storage ones. For this, the user needs to get a larger gas pipe. To increase the gas line according to the tank size take help from a licensed contractor.

Replacing the Old Water Heating Unit

If you are using the new unit to replace the older storage unit follow the listed steps

  • Turn off the gas supply, water supply, and any other electric supply to the unit.
  • Once the unit is fully disconnected drain the water inside the storage tank.
  • Disconnect the gas and water line from the unit.
  • Discard your old unit. Ask any nearby recycling company for information about how to dispose of the unit properly.

Placing the Water Heater

Tankless water heating units need direct venting to the outside. Look at the user manual for instructions about how to vent the unit directly.

  • Choose a location for the water heater that allows easy direct venting to the outside. Follow the installation instructions in the manual to ensure the safety guidelines are followed properly. Ensure you have followed the proper vent requirements like the distance from the window, the door is minimum.
  • Make a mounting box for the new unit using lumber and plywood. Build the box strong enough so it can bear the weight of the heating unit. Secure the mounting box to the basement wall using anchors.
  • Now mount the tank-less water heater onto the mounting box securely following the manual instructions.
  • Installing gas line
  • To make a gas connection you need to have some prior experience if you have not done any such job before then take help from a professional.
  • If your gas line size is fine according to the current water heater size connect the same line to the water heater using a threaded black iron pipe. The length of pipe and fittings you need will depend on the length of the pipe.
  • Once the gas line is connected place a shutoff valve and Sediment trap. Use the manual for instructions about how to install them.
  • When making gas line connections use the thread designed specifically for the gas lines. Once you are done with all the connections use a pressure test gauge to check for gas. Gas line installation is the most complex job.

Newbies should not try to do this by themselves at all. Taking help from a licensed contractor is always recommended.

New Water Lines

  • Connect the water supply line to the water heater. To do this follow the manual instructions. Run the new cold and hot water lines to the unit.
  • Use a sanding cloth to clean the area. Use a deburring tool for the cut sections.
  • For the remaining copper sections dry fit everything. Use a brush to clean each joint.
  • Bell hangers help hold the pipes in place. This will make it easy to apply pipe insulation later on. See the user’s manual for more detailed information.

Installing Pressure Relief Valve

This is a safety step. The pressure relief valve helps get rid of any excess pressure that builds up inside the unit due to water overheating. This prevents any hazardous situation. Install a pressure relief valve according to the instructions given in the manual.

Turn the water supply on and check for any water leakage. Turn the Gas supply line on and again monitor for any possible leakage. Once you have made sure that no pipe is leaking and all connections are proper then turn off the valve and carry on with the installation process.

Vent Valve

Use a silicone sealant on the vent shaft of the water heater. Use a section of the stainless steel vent pipe. Make sure the opening is pointing in the direction where the water heater will vent. Cut out the vent hole. Place flange into the vent hole. Connect the vent hood and replace the sidings. PVC pipe can be used for venting too. The process of installation will be the same as above.

  • Turning on the hot water tap
  • Turn on the hot water faucet so the air can move out. Now turn the tap off.
  • Connect the water heater. Insulate the hot water pipes. Turn on the gas supply line. Follow any special guidelines given by the manufacturer regarding startup.

Installing a tankless water heater is not an easy job. We hope that our guide about How to Install a Tankless Water Heater will benefit you when installing a tankless heating unit yourself.

If you are not experienced enough then get help from a professional. Larger homes will need more than one unit. If the number of units is not increased according to demand it will result in a longer time needed for water heating. Now you are done with the job and enjoy a hot water shower anytime.

You can also watch this video tutorial:

Video Credit: This Old House

Where to Install the Tankless Water Heater?

Finding the right location for a tankless water tank can sometimes be a difficult task. If you do not place it in the right location, you will not see the required results. Apart from that, such things should be fixed by some professionals because they know how to do it and the accurate place to locate tankless water heaters. However, if you really want to do it by yourself, then you need to focus on a few important things. So, in this article, I will talk about some of the important factors that will help you in knowing where to install the tankless water heater.

Given below is the list of some of the important factors that you must keep in mind when you install a tankless water heater. There are multiple things that can help you to achieve the best outcome. So, considering various aspects can provide long-term benefits.

1. Warm Place

Choosing a location that is warm is one of the most essential things that you need to consider while installing a tankless water heater. You need to make sure that the location is not too cold because it will influence the water heater in a negative manner. The water in the tankless water heater should not freeze because it will have negative effects.

So, you should seek some professional help so that you do not face any issues later on. The experts will fix the water tank in a proper location which will be effective in the long run.

2. Protected From Sunlight

Another important thing while installing the tankless water heater is that it should not be exposed to sunlight directly because it can damage it. Other than that, you also need to find a location where the water heater is not directly exposed to rain or insects.

The best place that you can choose is the one with a shade that can protect the water heater from changing weather conditions. You can place it inside the house because that will be the most suitable option. No damage can occur when you have installed the tankless water heater inside the house.

3. Near The Faucet

The water heaters should be placed somewhere near the bathroom of the sinks if you want effective results. If the bathroom is upstairs and the water heater is downstairs then it will not be much effective and the water will not be warm. In such a situation, you will need to install more water heaters near the bathrooms.

This will be an expensive thing to do. So it is better that you place it near the faucet that you frequently use so that you experience the best outcome. This is an important aspect that should be kept in mind while fixing the tankless water tank.

4. Dust-Free Location

Dusty or polluted areas are again problematic and lead to various issues in the water tank. The major reason for the problem is that the dust particles block the heater’s ventilation system.

This can result in the burning of gas which is really dangerous. Choose a place that is protected from all such things and the most appropriate place would be some sheltered area where dust or other harmful particles cannot reach.

5. Away From Humidity

Humidity and too much moist place can also damage the tankless water heater. It is not easy to always keep an eye on the water heater. So the best thing you can do is to place it in a dry location so that you do not face issues later on.

Moisture is also harmful to the tankless water heater’s burner because it can lead to corrosion and rusting. Humidity can damage the water heater in the long run and you may need to replace it with a new one. So, keep in mind all these factors if you want to avoid problems later on.

6. Easy To Access

Make sure that you install your tankless water heater in a place that is accessible. Accessibility is an extremely important thing to consider because, without it, you cannot maintain the water heater. Maintenance is required after every few days so considering this aspect can prove beneficial. You can make the required adjustments whenever you want if you have the accessibility.

Moreover, if you have been using the traditional water heater for a long time and now you want to replace it with a tankless one, then you need to consider a few things. It is better to adjust the tankless water heater in the same place where the traditional one was located.

The reason behind this is that the pipes and connections are already there so you do not need to go out of the way to install the entire system again. The gas lines are already there and all other systems are already installed which can be more convenient. So, locate the tankless water heater in the same place.

Where to Install a Tankless Water Heater Infographic

Where to install a tankless water heater Infographic


Can you install a tankless water heater anywhere?

Yes, you can place the tankless water heater anywhere. However, this will affect the performance of the water heater. Water heaters are usually small in size which means that they can easily fit into small areas. You can place them in cabinets or any other such place. The laundry room is another place where you can install the water heater. So, it totally depends upon your requirements.

Can a tankless water heater be installed in a closet?

They have a small size so that they can definitely fit into a closet. Just make sure that whichever place you choose is dry and dust-free. Moisture can damage the tankless water heater.

Can you put an outdoor tankless water heater in a garage?

Yes, you can surely place it in a garage and there is no harm in fixing it there.

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With years of experience under his belt, Adam decided to put his water heater knowledge to work. By providing high-quality content and expert guides, Adam hopes to help anyone looking for expert water heater advice.