One of the most overlooked appliances at home is a water heater. This particular gadget is often used yet needs to be addressed. 

With a water heater, one can enjoy a long comfortable bath or have enough hot water to wash the dishes. That’s why keeping your water heater running and in good condition is vital. 

Interestingly, we only put our water heaters at the forefront when there’s an issue. That’s when you start wondering how long a water heater takes to heat up. 

Or, more explicitly, how long a hot water heater should take to heat up after installation. This post will address all your concerns about water heaters, so keep reading.

This post will answer the question, “how long does it take for a hot water heater to heat up after installation,” so read on and learn more.

How Long Does It Take for a Hot Water Heater to Heat up After Installation?

The time it takes for a new water heater to heat up will vary depending on the size and type of water heater. A well-installed gas hot water heater will heat up faster than its counterparts. 

Generally, a 40-gallon gas water heater will take about half an hour to 40 minutes to provide hot water. Similarly, a larger tank of up to 80 gallons will take an hour or so to heat up. 

How Long Does It Take for a Hot Water Heater to Heat up After Installation

On the contrary, electric water heaters will take a little while after installation. Typically, it will take about 60 to 80 minutes for a 40-gallon electric water heater to heat up and about 2 hours for an 80-gallon electric heater to provide hot water.

Types Of Water Heaters And Heat-Up Times

1. Tankless Water Heaters

Tankless water heaters only heat and provide hot water on demand. This process is instant, meaning it can take up to a minute to supply hot water. 

Also, a tankless water heater is very efficient unless every household member strives to get hot water simultaneously. You may experience a lukewarm or hot water shortage in such a scenario. 

2. Tank Water Heaters

Unlike tankless water heaters, these types of heaters keep water. As such, they take time to supply hot water, roughly 30 to 40 minutes, depending on the heater BTU and the tank size. 

BTU is the British Thermal Rating, often referred to as the amount of heat produced by a gas heater to increase the temperature of ½ a liter of water (a pound) by a degree Fahrenheit. 

3. Gas Water Heaters

Gas water heaters perform similarly to tank water heaters. The only difference is that gas heaters run on explicit gas while tank heaters operate on gas or electricity. 

Generally, it takes 30 to 40 minutes for a gas water heater to supply hot water. This may seem like a long time when running out of time, but it’s worth noting that once the water heats through, it’s stored in the tank and transmitted through pipes when needed. 

Also, how fast hot water reaches you depends on how well your pipes are insulated and how close the water heater is to your shower or faucet. The shorter the distance, the faster hot water travels through your pipes to the taps. 

4. Electric Water Heaters

These water heaters take about an hour or so for their tank to heat up thoroughly, which is twice as much time that gas water heaters take to heat up.  

This is because the heat produced by electricity is slower than that produced by the fire. Also, unlike electric heaters, heat dissipation in gas water heaters is enhanced as heat moves upward with the burner at the tank’s bottom. 

How Long Does It Take for a Hot Water Heater to Heat up After Installation

The heating element in an electric water heater is usually located at the side of the tank. So when heat naturally rises, it travels to the other side of the tank,  taking longer to heat up. For this reason, electric water heaters have smaller volumes than gas water heaters. 

5. Solar Water Heaters

While these heaters are rare, some homeowners install solar panels and use the energy to run water heaters. Solar water heaters can supply adequate hot water if you reside in a region with plentiful sunlight throughout the year. However, when winter strikes, you must back up your solar system with an electric or gas water heater.

Reasons for a Slow Hot Water Heater

If your gas or electric water heater is running slow, there are a few things you should check out. Below are some reasons why your water heater may be running slow:

1. Distance

The distance between your water heater and the faucets determines how fast hot water travels through the pipes to your taps or shower. The farther your water heater is from your faucets or showerheads, the longer it will take hot water to reach you.

2. Low Volume Restrictor

Appliances such as showers often come with restrictors controlling water flow. While these devices help manage water bills, they can cause delays in hot water delivery. If you suspect this is why your water heater is running slow, then it would be best to call a plumber and have your faucets or shower heads inspected.  

3. Your Water Heater Is Too Old

Most water heaters have a lifespan of about ten years; if yours is older than that, it’s on the verge of breaking down. Your old water heater calls for a replacement if it’s no longer performing as it used before. 

4. Sediment Buildup

Another potential reason for a slow water heater is sediment buildup. With time, sediment accumulates inside your heater’s tank and prevents the movement of thermal energy. Fortunately, you can resolve this issue by flushing the tank. You can choose to DIY or hire a professional plumber to help you out.

5. Your Water Heater Could Be Too Small

Sometimes, your water heater must be more significant to accommodate every family member. If you’re experiencing slow hot water delivery, it could be that your water heater is too small. In such a situation, upgrading your water heater will go a long way toward enhancing the speed of your water heater. 

3 Ways To Speed Up Your Hot Water

If you’re still experiencing slow delivery with your water heater, below are a few steps to speed up your water heater, so read on:

1. Get a Hot Water Recirculation System

A recirculation system will enhance water movement from the heater to the faucets. It will also recirculate the remaining hot water to the tank to have hot water at hand when needed. Circulators can be operated by a thermostat or timer, effectively utilizing your water heater’s efficiency. 

2. Upgrade to a Tankless Model

Upgrading to a tankless model is another way to speed up your water heater.  As the name suggests, this type of water heater supplies hot water on demand or when needed. 

Therefore, tankless water heaters have become more affordable and popular in many households. Should you consider upgrading your water heater, ask your plumber to walk you through the options and the benefits of going tankless

3. Consider a Larger Tank

You may be surprised to find out the issue is not as big as you had envisioned —  you may just need to upgrade the size of your tank. If your tank is sized for two, but your household has increased to five or six, that could be why you’re experiencing a slow hot water delivery. 

If this is the case, a plumber is better positioned to guide you on the best options for your family size. These are just a few steps you can take to enhance the delivery of your water heater. 

Factors That Affect Heat-Up Time

Apart from the features discussed earlier, such as BTU and tank size, many other factors could affect the heat-up time of your new water heater.

Incoming Temperature

Whether it’s a tank-style or tankless water heater, the incoming temperature will influence the heat-up time of your new water heater. Although the heating units of a tank reserve and keep water heated up, the inbound temperature should not significantly affect it. 

How Long Does It Take for a Hot Water Heater to Heat up After Installation

Tankless units, however, feed incoming water on demand. This process is instant so you can expect hot water from your faucets within seconds. Sadly, if the groundwater temperature is too low, you may have to wait a little longer for the water to heat up. Nearly all water heaters are affected by the temperature levels in the area where they are stored. 


While water heaters seem relatively straightforward compared to other household equipment, this mechanicals call for more. If your heating system isn’t performing as expected, you may need to call a professional to check out any issues with the settings or calibration. 

Age/ Maintenance Issues

Like any equipment, your water heater’s age, and state can significantly impact its performance, including how long it takes to heat up. A lack of regular maintenance often leads to sediment buildup in the pipes and causes efficiency problems. This is especially true if you reside in areas with hard water. 


Your water heater’s location determines how fast hot water reaches you. How far your water heater is from your faucets will determine how fast water reaches you. Usually, water moves through the heating system and pipes before reaching the taps. When installing a new system, a professional plumber should bring this to your attention. 

Pipe Diameter

Besides piping length, the width of your pipes could also impact the heat-up time of your water heater. A broader tube is ideal as it allows more water, but more water should be heated before sufficient pressure is achieved to push through the remaining pipes. 

In a nutshell, there’s a heater out there to accommodate everyone’s needs. Whether tank-style or tankless water heater, your needs should be at the forefront before settling for one.  

Frequently Asked Questions

1. What to Do After Installing a New Water Heater?

Once you’re done setting up your new water heater, the next step is to analyze the draft. Ensure all exterior doors and windows are closed before turning on the exhaust fans in your kitchen and bathroom. After that, open a nearby hot water faucet until the gas burner ignites. 

2. How Long Does It Take To Get Hot Water After Reset?

Unless you’re operating a tankless water heater, you’ll have to wait a couple of minutes for your heater to supply hot water after resetting. However, the time may vary depending on the size and type of the tank. 

After resetting, a gas water heater should supply hot water within half an hour. On the other hand, electric heaters should be able to provide hot water within an hour after resetting. 

3. Do New Hot Water Heaters Need to Be Flushed?

No, you don’t need to flush a new water heater. However, depending on how hard your home’s water is, you should flush your water heater yearly. Water heaters play an integral role in our daily lives, so performing regular maintenance will go a long way to ensure that it stays up and running for an extended period. 

4. Why Is My New Water Heater Not Heating?

If your new water heater isn’t supplying hot water after installation, there are two reasons for this. First, there is no electric power supply, and second, dry fire might have burned the upper heating system during installation. You may need to call a professional if the issues mentioned above differ from why your new water heater is not heating.