How Long For A Hot Water Heater To Heat After A Reset?

There isn’t much that can match up to ruining your day quite like an ice-cold shower. Unfortunately, if you have a faulty water heater, this may become your new normal. Whether the reset button on your hot water has tripped, or you initiated it yourself, you may find yourself wondering how long until you can enjoy hot water again.

Though it would be nice, water heaters aren’t magical devices that house an endless supply of hot water. It takes time for them to turn that undesirably cold water into the steamy warmth that everyone loves. How long it takes them to heat water varies, as not all water heaters are the same and come in a range of different sizes, with the most common being 40 gallons.

Aside from size, there are a number of factors that dictate how long your water heater takes to heat up. So, if your hot water heater has recently been reset, you can expect it to take anywhere from 20 to 80 minutes to heat. We’ll explain how we arrived at those numbers and also provide specifics based on the type of water heater you have, its size, and a variety of other factors.

The average gas tank water heater will take roughly 30 to 40 minutes to heat up after reset. Although, the time may be slightly less depending on the temperature of the hot water that is currently in the tank. The two factors that determine this time frame is the size of the tank and the heater’s BTU (or British Thermal Unit) rating.

The BTU rating describes the amount of heat that is required to raise one pound of water one degree Fahrenheit. A heater that has more BTUs will heat water faster. A traditional 40-gallon hot water tank will have about 330 pounds of water when full. Put simply, a 40,000 BTU system and a 40-gallon tank will need half of a minute to heat each pound – or approximately 40 minutes total. If your tank is smaller in size or has a higher BTU rating, the heat up time will be much longer.

Hot water heaters powered by electricity will generally take double the amount of time to heat up when compared to their gas counterparts. Although more economical, electric elements simply cannot match up with the high performance of gas-powered heating systems. From the moment new water enters the tank, it will take about an hour for the electric water heater to heat the entire 40-gallon tank. Again, if the water is heating up after a reset, this number may vary slightly based on the temperature of the existing water.

Many larger homes elect to purchase a whole house gas heater, as opposed to an electric one, solely based on the speed it takes to heat. However, electric hot water heaters are great for smaller homes or smaller water demands.

Whether the unit is powered by gas or electricity, a tankless water heater can service hot water “on-demand”. Therefore, the only thing that determines how long it takes to receive hot water at your faucet is the distance from the heater to your appliance. So long as the system is working properly, installed correctly, and sized appropriately, it should only take about 15 seconds. It may take slightly longer for hot water to travel through the pipes in larger homes, but should still be far less than a minute.

In both gas and electric tankless water heaters, the water will not start warming until you turn on your faucet, dishwasher, or other appliance. It should be noted that although electric tankless water heaters can provide hot water within moments, they may take slightly longer than their gas counterparts. This simply has to do with the sheer power of gas heat.