How long does a water heater take to heat up?

As you can easily imagine, water heaters don’t have a standard heating time. The time they need to heat the water can vary depending on a lot of factors.

Therefore, in this article on how long does a water heater take to heat up, we’re providing an average time, but we’re also focusing on those factors that affect the water heating time.

This way, perhaps, you could even act on those factors to obtain a quicker heating system.

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How long does a water heater take to heat up?

Let’s start with the reason why you end up in this article: how long does a water heater take to heat up?

Well, the average time is 30 minutes. However, as we’ve mentioned, optimized systems can be even quicker and take only 20 minutes to heat up.

On the contrary, if your unit is particularly big or if there are some issues, the process can be long and take even 40 minutes or more.

Now, it’s important to know what factors affect the heating time. If you can act on any of these factors to improve your water heater’s performance, you should absolutely do it: improving the performance not only means that the water heats up more quickly but that your system becomes optimized and, therefore, energy-saving.

As you may know, energy saving always determines money saving, especially in the long term.

Read: Holmes Heater Review

Also Read: 10 Best Rheem Water Heater


Factors that affect the heating time

1. Dimensions of the tank

Of course, if you have a smaller tank, it’ll take a shorter time to heat it up. You can consider these average times:

  • 40-gallon tank: 30-40 minutes heating time;
  • 50-gallon tank: 40-50 minutes heating time;
  • 80-gallon tank: 60-70 minutes

In most houses, the water heater features a 40-gallon tank; that’s why the average heating time is considered to be between 30 and 40 minutes, as we’ve mentioned in the previous paragraph.

2. Original water temperature

All houses are connected to the town or municipal water system. Water flows and enters your house at a certain temperature. Of course, the higher this temperature, the quicker the heating time.

This also means that you can expect shorter times during summer and longer during winter because – of course – water would flow inside municipal tubes at a higher or lower temperature, respectively, during summer or winter.

3. Power source

As you may know, water heaters can heat water through electricity or gas. Gas water heaters are more efficient, and therefore they can take shorter times to heat up the water.

On the contrary, if you have an electric water heater, you can expect longer times. This is why gas water heaters are considered more efficient.

4. First-hour delivery rate

The first-hour delivery rate or FHD rating is a parameter that can tell you how powerful your water heater is. By powerful, we mean quick when it comes to heating water.

The FHD rating tells how many gallons of water the unit can heat in an hour. Of course, the higher the FHD, the shorter the time it’ll take to heat up the water.

Read: 10 Best 70-Gallon Water Heaters 

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