What's Required to Change From a Tank Hot Water Heater to a Tankless Hot Water Heater?

Tagged As:

Now that you have opted to change out your tank hot water heater with a tankless hot water heater, you’ll be saving up to $100 or more annually on your water heating bills. But before you make the big move, you’ll need to plan beforehand. Including obtaining building and plumbing permits, choosing the right solution, gathering the tools necessary, and determining the overall expenses.

Construction and Plumbing Permits

Before replacing your tank hot water heater, ensure you contact the local municipality for information about obtaining building and plumbing permits. Some state laws require replacement water heaters to be anchored or braced to resist motion during an earthquake, which can cause water or gas line leaks and electrical wiring harm. The easiest way to brace a water heater would be to install a pre-approved bracing system, which can be found at most hardware shops.

Selecting the Ideal Product

Tankless hot water heaters are rated by the number of gallons of warm water they create per minute. The more likely you are to have the shower, dishwasher, and clothes washer moving at once, the bigger the gallons per minute you’ll need. You also want to size it for your peak demand program, that’s usually during the morning when everyone is carrying a shower at precisely the exact same time. If you install a tankless hot water heater which is too small, your warm water flow can diminish when multiple plumbing fixtures are turned on concurrently. That’s why you need to work very carefully with your producer to estimate the hot water demands in your house.

Gathering Tools

The tools necessary to set up your new tankless hot water heater are fairly basic and are available on your toolbox. You will need a power drill, a reciprocating saw, hole saw, stud finder, tape measure, level, adjustable wrenches, screwdrivers, a hacksaw and a few great pliers. If your installation contains aluminum pipe, you’ll also need a propane torch and a pipe cutter. Do not forget your safety gloves and goggles. Finally, ensure you consult with manufacturer’s manual to get product-specific guidelines when installing a tankless water heater.


The good thing is that by choosing to do it yourself, you’ll be saving anywhere from $1,000 to $2,500 in installation costs. The bad news is that purchasing your new tankless hot water heater will cost you a bit more up front, which range anywhere from $800 to $1,200 without the contractor’s discount. The actual sticker price will change among system forms and from model to model. More savings accrue in a replacement job when you use the same location your old hot water heater occupied. This minimizes the materials you want to buy, as you can often use the existing vent pipe, water pipe and gasoline line.

See related