Gas Hot Water Heater Installation

Charlie Hardcastle

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 A working water heater is a lifesaver. It is one of the most valuable items you may have for your home. They are generally less expensive to run than electric water heaters, produce high-volume on-demand hot water, and quickly recharge to provide more for those long showers and baths.

When considering a water heater installation project, one factor to consider is the installation cost. Installing a 40-50 gallon water heater with a water heater tank can cost anywhere from $400 to $900. A tankless water heater installation typically costs between $1,470 and $2,500. The ultimate cost of owning a water heater is determined by a variety of factors, including the number of people who will use the heater, running costs, and home modifications.

Before you go out and buy a new water heater, keep in mind that water heater installation is not a job for the inexperienced. You can injure yourself attempting the installation if you don’t know what you’re doing. And if you make a mistake, you risk causing damage to your property.

Identifying the type of gas water heater you have, selecting a new one, and removing the old one are all necessary steps in replacing a gas water heater. You’ll need to know how to connect the new heater’s water and gas lines, as well as how to light the pilot light.

Continue reading if you’re up for it.

What are Gas Water Heaters?


Modern bathroom interior with freestanding tub

A gas water heater is a tank that uses a gas-fired burner at the bottom to heat the water. The hot water begins at the bottom and climbs to the top, where it is drained by a discharge tube. Gas has several advantages for heating your home’s water, including cost, convenience, and efficiency. 

Natural gas is not only less expensive than electricity, but it is also more dependable. Your gas supply remains unaffected in the case of a power loss. Furthermore, a gas heater heats a new tank of water faster than an electric heater when a water tank runs out of hot water.

However, to install a gas water heater, you’ll need more experience, and the process will take longer. If you’re considering a gas water heating system, there are several advantages and disadvantages to consider, including:

  • Electricity is more expensive than natural gas. This is the way to go if you want to save money on your utilities.
  • The water in gas-powered machines heats up quickly.
  • Compared to an electric water heater, a tankless gas water heater is far more effective and efficient.
  • Your water heater will continue to function normally even if the electricity goes out. This can come in handy during storms or other power disruptions.

Can I Install it by Myself?

If cost is your primary issue, remember that hiring a professional may be more cost-effective in the long run — but if you’re confident in your abilities, you can certainly handle a gas water heater installation on your own.

According to Consumer Reports, 90 percent of water heater replacements are due to the failure of the previous water heater. You don’t want to have to learn how to install a gas water heater while water is gushing all around you. It can also be dangerous to perform it on your own if you have no prior experience or knowledge of the subject.

It is far better to entrust the installation to a professional if you are unclear about what to do. Gas leaks are a major threat to your home and the environment, so this is not a DIY project you can afford to mess up. You may experience leaks if you misconnect it.

How to Install a Gas Hot Water Heater


white ceramic sink near white ceramic sink

If you’re ready to install a natural gas hot water heater (see also ‘ Can A Hot Water Heater Last 20 Years? ‘), follow these steps to make the process go more smoothly. Please do not work on the gas pipes unless you have received the necessary training.

  1. Drain the water heater tank.

The water supply to the device must be turned off. The gas control valve must be turned off as well. The gas supply can then be turned off.

Turn on the closest hot water faucet and let the water run until it cools down. Then, using a garden hose, pour the leftover water into the drain, buckets, or another safe location outdoors.

Disconnect the Lines

After making sure the gas supply to the hot water heater is turned off, you’ll need to attach the gas line with the proper tools. This step should take place at the union fitting if the pipe is black iron.

Then, above the tank, disconnect the water pipes (see also ‘ Banging Water Pipes: Causes And Simple Fixes ‘). If the pipe has a soldered connection, you’ll need to execute this step with a tube cutter.

After you’ve completed those tasks, you’ll need to disconnect any gas pipe that is still connected to the gas valve. Keep the sediment trap and tank tee intact if it’s made of black iron.

3. Remove the exhaust pipe.

The exhaust from your natural gas water heater extends outside the house. The screws that link this line to the water heater must be removed. Once it’s disconnected, examine the components for damage or rust, and replace any flue that appears to be in bad shape.

You can now properly dispose of your old water heater.

4. Replace the old gas water heater with a new one.

Position the new water heater so that the controls and burner are easy to reach. Make sure to follow the manufacturer’s instructions and local codes, especially the minimum clearances required for combustible materials.

As needed, use a level and shims to finish the installation. Attach the flue hat to the exhaust vent once it’s finished. To meet modern code requirements, you must utilize a non-metallic plastic vent pipe.

Attach the water line connections and heat trap fittings after they’ve been secured. This step may entail measuring and cutting the lines to the desired length. Try to dry-fit everything before sweating the copper connections to check everything works as planned.

It’s also a good idea to start with the threaded fittings. Allow them to cool completely before attaching them to the heat trap components. Then, apply flux, assemble, and solder using a propane torch. You can then link the waterline, connect the pressure relief valve, and prepare the device to take water.

5. Connect the Gas Supply

The threads should be cleaned with a wire brush and rag before connecting the gas line. When joining the black pipe threads, use thread seal tape or pipe compound. If you’re using an installation kit, make sure you follow the directions.

Assemble and secure the fittings with two pipe wrenches. Because the union fitting connects the new line to the current source, it should be installed last. To secure the flare connection, use a natural gas-rated pipe joint compound.

Check for leaks and switch on the water heater after lighting the pilot. This is how a gas hot water heater is installed.

Signs You Need a New Water Heater

It might be tough to tell if your water heater merely needs maintenance or if it is time to replace it. The following are some obvious signs that a new water heater is required:

Discoloration and Bad Taste

Water that is discolored or tastes terrible is an indication of internal tank corrosion, and there is no way to remedy it. Your water heater should be replaced.



grayscale photography of faucet

A leak from the tank itself, possibly near the water connections or heating equipment. Replace your water heater if the tank has deteriorated and started to leak.

Loud Noises

Loud noises coming from your device indicate that corroded material and hardened minerals are bursting free from the heating elements inside. It’s most likely filled with hardened substances like this.

Old Appliance

In case your water heater is 10-15 years old — at this age, it has reached the end of its useful life, and even if it isn’t having difficulties now, they could occur at any time. Your water heater should be replaced.

How Much Does a Gas Water Heater Installation Cost?

Installing a traditional tank-type water heater costs between $800 and $1600 on average. This covers the water heater unit as well as regular installation work. Every further electrical or plumbing (water or gas) work will increase the overall price. A new tankless water heater can cost anywhere from $1,000 to $3,000, depending on the device and installation.

The cost of installing a water heater in your home is determined by several factors, including your location, the kind and model of the water heater, whether it is electric or gas, and any other work that is required.

Additional Installation Fees for Water Heaters

Installation of a water heater may incur additional fees. Typical cost estimates include the unit as well as a standard plumbing expense that does not require any additional work. Additional work must be considered into your cost estimate if it is required. Here are some of the most typical installation-related extra expenses.

Plumbing and Electrical Work 


man wearing black pullover hoodie holding tool

These additional costs are normally charged by the hour and can range from $45 to $150 per hour, including materials.

This may be essential when switching from one fuel source to another, such as from electric to gas. It can be essential to install new wiring (see also ‘ How To Wire Twist Lock Plugs ‘), replace or add water lines, or install gas lines. It’s possible that adding an expansion tank (see also ‘Expansion Tank Installation‘) will come at a cost.

Carpentry Work 

Depending on your installation, you will need a skilled carpenter to create a new area for the water heater and components, build an enclosure, add or modify existing framing or support components, or hang the drywall.

  • Depending on the materials used and the size of the wall, framing a modest wall can cost anywhere from $200 to $500.
  • Drywall installation and finishing can cost anywhere from $1,000 to $3,000 or more.
  • Any service involving structural components can be costly, with hourly rates ranging from $50 to $80.


Depending on your local authority, you may require a single permit or both a plumbing and an electrical permit. Additional construction or remodeling permits may be required if other work is involved. Permits are typically priced between $100 and $1500.

Gas Water Heater Installation Mistakes

You must avoid these water heaters’ installation mistakes to ensure that you do not waste your money. Follow these instructions if you’re shopping for a new water heater for the first time. It will help you stay on schedule with your water heater installation.

Failure to Follow Installation Procedures

Building codes and installation standards are in place to keep your house and family safe. Read all of the directions before beginning a water heater installation process. Also, make a list of the tools you’ll need for the project.

Missing a step, such as securing the water heater, can result in flooding and water damage to your home.

Refusing to Ask For Help with Your Water Heater Installation

It’s fine to accept that you lack the necessary abilities to finish a home improvement job. Installing water heaters necessitates a thorough understanding of plumbing, electricity, and gas. All of those skills take years to learn for professionals.

You will save money by hiring a professional who knows how to install a water heater (see also ‘Can Water Heaters Be Installed Outside?‘). They also know how to deal with any unexpected issues that arise during the installation. Would you be able to tell how to replace corroded supply lines? You most likely lack the essential tools to deal with any unforeseen problem.

Ready for a New Hot Water Heater Installation?

A gas hot water heater (see also ‘Gas Hot Water Heater Troubleshooting‘) is a great investment for any homeowner and is one of the most popular types of water heaters on the market. Installing a gas water heater in your home could result in cheaper energy bills and more efficient water heating.

Installing a water heater is a complex but necessary undertaking. However, if you don’t know how to operate with natural gas, this is a job that should be left to a professional rather than being deemed a do-it-yourself project. If you’re up to the task, remember to apply this guidance to prevent making these costly errors.

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