Things To Check Other Than Tankless Water Heater Gas Line Size During Its Installation

Many people opt for tankless water heaters for instant heating solutions. However, installing one in your bathroom or on the top of the wash basin might take around 2-4 hours and isn’t exactly a task for the average DIY crafter. 

Let’s review a few more factors such as capacity and tankless water heater gas line size, that you should keep in mind when installing a tankless heater.

Tankless Water Heater Gas Line Size Upgrades

tankless water heater gas line size

Unlike traditional water heaters, instant water heaters do not hold a certain quantity of water in them. Instead, these appliances supply hot water on demand. This means that the mechanism is inherently quite different from a conventional water heater with a storage tank.

This also means that you might have to change the gas line size and arrangement for the best results. Additionally, these heaters are smaller in size than conventional ones. This upgrade will take up less space, which is a win on all sides. 

As a result, you can install them even within a small washroom. Usually, tankless water heaters require ¾ inch gas lines – however, you can also use a ½ inch or 1-inch gas line based on your home’s specifications. 

Consult an expert to know the perfect gas line size for your instant water heater.

Removing an Old Heater

Once you have set the gas line right, it’s time to take down the old water heater. To start the process, first, disconnect the old heater with every source of power and water supply. Open the hot water faucet and drain the water inside the tank of the old heater.

Once the heater is empty, disconnect it with the power supply lines and the water supply lines. Now, your task of old heater removal is almost complete.

You can connect with your local authorities to learn about the best and the most eco-friendly ways to discard old appliances. Please dispose of your old tankless water heater as recommended.  If your water heater is recyclable, you can dispose of it in an even more effective manner. 

Installing Your New Water Heater

First, you need to select a location where you want to mount the appliance. It can be in a corner of the washroom, on the wall above the washbasin, or anywhere else it will fit that makes sense to you.

There is one factor you need to keep in mind while selecting the water heater’s position: the vent arrangement. Instant heaters are generally direct vent appliances.

This means you do not need to connect the vent lines to a chimney. Check the manufacturer’s manual to know the appropriate conditions to place an instant heater. If your choice of location does not contradict any of the conditions mentioned in the manual, you can install it without any worry.

The best way to install the device would be to place it inside a wooden box made of durable lumber and plywood.  This will keep the device a few inches away from the wall surface and protect it so that it has the potential to last you for a very long time. 

A sturdy wooden box capable of holding the weight of the heating unit is ideal for mounting the instant heaters. Now that you know how the process goes, you can install the water heater inside the mounting box effortlessly. 

Gas Line Installation

It is important to remember that the installation process began with uninstalling the power supply lines. Now that you have mounted the instant heating device on the wall, it is time to reconnect the appliance with the gas supply line.

Note that if your previous gas line size is adequate, you do not have to take the pain of buying a new one. This probably isn’t a judgment call you should make alone, though. Discuss with an expert gas line contractor to check if the existing line is fine for the new device.

On the other hand, if your previous gas line arrangement turns out to be improper for the new appliance, you need to reinstall the gas line that matches the new machine’s specifications. Depending on the location of the heater, you might also have to change the gas line tee and a few other peripherals.

The gas line installation process can be an extensive alteration or a few touch-ups hither and thither based on what your existing set-up is and what the new machine requires. Gas shut-off valves are also critical here. To ensure the safety of yourself and those around you, make sure to integrate these valves to control the power supply.

Water Supply Line Installation

Much like the power supply lines, you need to reconnect the heater with the water supply lines. Using copper pipes for this purpose is always the best choice. Once the power supply is on, you can begin with the water supply connection process.

You will see fairly easily how to install a tankless install heater with two different water supply lines meant for hot and cold water. 

Water pipe installation has to be flawless to let the device function at its best capacity. Don’t hesitate to call on an expert if you are unsure of or are uncomfortable with this process.

Pressure Relief Valve Installation

An instant water heater heats up water instantly creating a certain pressure inside the system. This is more of a safety valve that keeps the pressure level under check within the heater’s system.

You will find detailed installation instructions inside the manufacturer’s manual. Even for pressure valve integration, these manuals provide in-depth specifications.

If you pay attention to detail, this is a step you can probably complete on your own. 

Exhaust Vent Installation

This is the last step of installation and after this, you can use your instant water heater without any worry. However, you should be as cautious as you have been throughout this installation process for the last step as well.

Exhaust vents are critical for the longevity of instant heaters. This means that you should follow every instruction given in the manufacturer’s literature for installing it.

Factors to Consider While Buying an Instant Water Heater

tankless water heater gas line size

In many places, the summers are as hot as the winters are cold. Apart from bathing, water heating becomes essential even for washing hands during the winter season. Many households and offices use instant hot water solutions to keep the water working well. 

The best part about using these tankless water heaters remains their precise size and instant heating capacity. No matter the space, you can accommodate these hot water solutions effortlessly.

Additionally, you do not have to wait for 5 or 10 minutes to wash your hands with hot water. The instant heating technology does exactly as the name suggests. 

This is why many households and offices find tankless instant water heaters more useful than traditional ones with big tanks. Before you buy a tankless water heater for your home, make sure to learn about certain specifications that control the efficiency of these heaters.

The following are a few such factors that control the functionalities and efficacy of an instant water heater.

Energy Efficiency

Whenever you buy electric appliances, check how energy efficient the device is. Higher energy efficiency would mean lower power consumption. This means that your bills will remain within limits even after using the instant heater frequently. 

Always remember that instant heaters require a lot of power supply to heat the water instantly. Therefore energy efficient devices are necessary.


Every house or office does not require a hot water supply for the same purposes. Some may use it for dishwashing and some for washing hands alone. You should check your requirements before buying an instant water heater. Based on your requirements, pick a capacity of the heater that would justify your needs.


It’s always important to consider your budget when searching for new home appliances.  As you decide which tankless water heater is the best fit for your household, remember that budget and other practical factors such as space should be taken into account.


In short, instant water heaters can be extremely useful if you buy them carefully and install them following the instructions. Check the gas line size for your tankless water heater before installing the device to ensure safety and optimal heating.