Informational Guide

How Long Does It Take To Install A Water Heater?

by Andrew

Without a water heater, you cannot take a hot shower, use the warm cycle on a clothes washer, or properly run a dishwasher—conveniences most of us take for granted.  

If you are contemplating DIY installation or switching to a new water heater type, you might wonder: How long does it take to install a water heater? This guide will give you a better sense of how long various water heater installations take. 

The first step in a water heater install should always be assessment. Most professional plumbing services will schedule a consultation for any planned water heater installations or replacements. If you want to go for a more energy-efficient water heater or change the size or location of your home water heating system, the professionals will discuss this with you. (Alternatively, if you are experienced with home projects and your intended replacement is almost exactly like your old hot water heater, then you can probably DIY it.)  

Assuming this is not a new home, the likely first step is removing the old water heater: First, turn off the water supply, gas (if applicable), and electrical input. Next, drain the tank of the old unit completely (unless you are one of the few who has a tankless water heater); once the tank is empty, carry or roll the old unit away.  

Next, put the new unit in place, but it is often the case that the gas connections (if applicable) do not line up perfectly with those of the new unit. Therefore, some readjustment usually has to be done; this is the part most likely to overwhelm DIY homeowners. (Alternatively, if you are putting in an electrical unit where you formerly used a gas-powered, you will have to put in a higher-voltage connection, which is definitely a job for a professional electrician.) 

Once everything is reconnected and the new unit is in place, fill the tank and turn the new unit on. Formerly, this involved lighting an actual pilot flame, but modern gas water heater ignitions only require some button-pushing 

Last, run water from your tap and test the system until you are able to reliably draw clean, hot water.  

man installing water heater

How To Install An Electric Water Heater:

How To Install A Gas Water Heater:

This video shows a professional-type replacement of a gas water heater, but, starting at 7:12, the expert addresses the changes made to modern tank water heaters that make them different from traditional models. 

Factors That Affect Water Heater Installation Time 

Water Heater Type:  

  • Energy Source
    Electrical units take less time because there is no gas connection/ventilation required. However, they do require a 220-/240-V electrical connection, which is not normal in United States homes. Gas water heaters, in contrast, simply hook up to standard American 110-/120-V electric sockets
  • Traditional Vs. Tankless:
    Tankless water heater installation tends to take up more time, primarily because many people are replacing tank units; the different build means connections must be reconfigured, even when the energy source is unchanged. If you are replacing a tankless with another of its kind, the entire installation should not take long: these water heaters are smaller and require no emptying/filling

Water Heater Size

Small residences can have 30- or 40- gallon water heaters, but most family homes run on 50- or 60-gallon tanks. Fortunately, these larger tanks take no more than half an hour to empty, but if your replacement is a tank water heater of similar capacity, you will have to wait an equivalent amount of time for the new unit to fill—it is a round-trip journey. Also, large tanks are cumbersome to move, especially through tight spaces. In contrast, tankless water heaters are always smaller than tank units, requiring no filling.

Location Of Water Heater Placement

If the new water heater and the old are the same basic type, it will not take long to install in the same place since the space and connections are already there. However, changes made to modern tank water heaters could present time-consuming issues. Many have energy-saving insulation, which increases their dimensions. In contrast, a perk of tankless units is that it is easier to put them closer to where hot water is needed, which reduces energy loss. However, this likely means a total change in location—and the need to install new electric or gas connections.

New Heater Or Replacement Heater

Generally, a new hot water heater similar to the old one takes much less time to install. Most professionals will schedule a consultation to help you decide what best suits your location, home structure, water needs, and energy-saving goals. This might end with a choice to install in a totally different part of the house; it might require an electrician to change the circuitry—both of which could create an installation that takes upwards of an entire day. 

DIY Or Professionals:

If you are a very handy DIY-er, you might ask, “Can I install a water heater myself?” Generally, yes—but it depends. Most DIY-ers should not get involved in electrical connection changes. Also, many DIY-ers are not comfortable soldering pipes; while soldering is often a necessary step, there can be ways to get around it. Finally, performing a DIY water heater installation might void your product’s warranty, so that is definitely something to consider. 


Heavy sediment build-up in a tank contributes to leaking and malfunction, but it also makes emptying more complicated. Also, if the previous tank has been leaking, time will be taken to dry the floor and repair water damage. Old gas or exhaust pipes, as well as old electrical connections—even if they have not caused a problem yet, should be inspected for deterioration and leaks before any new water heater goes in. 

installed richmond water heaters

How Long Does It Take To Install A Water Heater (For Different Types) 

Installing Gas Vs. Electric Water Heaters

Estimated time ranges are large—with 2 hours being a general minimum and 2 workdays being a general maximum. The state of your intended installation location (including its gas and electric connections) is actually the biggest determinant of how long a water heater installation takes. Gas and electric water heaters of the same build (tank or tankless) take about the same amount of time. However, because most households that go electric are changing from a gas-powered system, the installation likely requires electrical adjustments that take a couple of additional hours.

Installing Tankless Water Heater:

Tankless installations tend to take the most time (potentially more than one workday), only because most USA homes are converting from a tank system.

Otherwise, tankless water heater replacement is quicker and easier.

Gas tankless water heaters can be replaced in 4 hours or less if the gas system is in good condition; electrical tankless water heater replacements could take less than 2 hours if you already have the appropriate voltage

outdoor tankless water heater

People Also Ask (FAQs)  

What is the labor cost to install a water heater?  

As this article has illustrated, every water heater installation is different, taking a different amount of time and expense. Lowe’s, for example, gives neither estimate nor range on water heater installation cost. However, general findings suggest that $200-$2000 (not including the water heater or other materials) is a reasonable range. 

How long does it take to remove a water heater?  

Home Depot’s time and price estimates always include complete removal (disconnection, emptying, transport, and disposal) of the old water heater. This seems to be normal in the industry. Depending on size/tank capacity and condition of the connections, removal can take anywhere from 30 minutes to 2 hours. 

How can I lower the cost of water heater installation?  

There are tax deductions and refunds available in some regions when you choose a more energy-efficient unit, such as an Energy Star-certified tank, tankless, or solar water heater. DIY naturally eliminates labor costs, but most people do not have the expertise and tools to perform the installation/replacement safely and efficiently. 

How long does it take to DIY install my own hot water heater?  

If you have the tools and skills to perform the steps confidently, then you will take the same amount of time as a plumber, and you have the advantage that you can get started whenever you want. Otherwise, hiring a professional plumber is definitely faster, safer, and more efficient. General advice, even if just for water heater maintenance: have a circuit tester and a carbon monoxide detector, which is a safety essential in any building with a furnace or other gas-powered element. 

Does Home Depot install water heaters for free?  

No, they do not install for free, but both Home Depot and Lowe’s offer same-day installation—probably most helpful if you suffer a sudden malfunction and just want a replacement ASAP. They also offer financing options and service guarantees. 

How long after installing a new water heater do I have to wait for hot water?  

Once a tank water heater is in place and filled, it takes about 30 minutes to 1 hour to heat up, depending on size. A tankless water heater, in contrast, will give you hot water almost instantly after installation. 


Much of the time that water heater installation takes has to do with energy-efficiency updates to traditional units, as well as conversion to more eco-friendly electric or tankless water heaters. As technology improves and more people convert, the typical water heater replacement should take less than a couple of hours and be very DIY-manageable.