Who doesn’t want a quick hot shower on a chilly morning? And if you are planning to buy a heater, the first question strikes to your mind is; how long does a heater take to heat 50 gallons of water.

It is important to know that there is no fixed time for heating a 50 gallons water as several factors contribute to it like – the type and number of heating element, the temperature of the incoming water in the unit,  tank size, heater’s power source (gas or electricity ), etc.

There are mainly two ratings that determine the efficiency of tankless water heaters: the recovery and first-hour ratings. Both these factors are crucial in deciding the time it takes to heat up the water. The energy guide sticker on your heater indicates both these figures and helps you in determining the estimated time required by it to heat 50 gallons of water.

Let’s discuss their impacts in brief:

• First-Hour Rating

According to the tests specified by the U.S. Department of Energy for the unit, the first-hour rating is determined by the total gallons of water drawn from the hot water heater during one hour. This is done with the unit which is set to a water temperature of 135 degrees Fahrenheit. The test results are indicated on the energy guide sticker of the unit.

• Recovery ratings

The recovery rating depends on the amount of power received by the unit. Gas hot water heaters are more efficient as compared to electric ones as they take about half the time to heat up. For a 50-gallon hot water heater to heat up, the determining factors are the temperature of the water coming into the unit, the temperature set to heat the water and the power supply.

Electric Hot Water Heater Recovery

A 50-gallon hot electric water heater having a 5,500-watt heating element set at 120 degrees requires about 1 hour and 20 minutes heating the water entering the heater at 60 degrees. If we slightly change the parameters by keeping the temperature of the water entering this same tank at 40 degrees, it takes about 1 hour, 47 minutes to heat it up to 120 degrees. On the other hand, for 70-degree water entering the tank, it takes about 1 hour, 6 minutes to reach its full heat of 120 degrees. Thus a 10-degree variation in the temperature of water inflow can have a significant effect on the heating time.

Gas Hot Water Heater Recovery

To calculate the recovery time for a 50-gallon gas heater, we divide the electric hot-water heater recovery times in half. In a 50 gallon tank, for water inflow at a temperature of 40 degrees; it takes about 53 1/2 minutes to reach 120 degrees. The same for 60-degree water inflowing the tank is about 40 minutes and for 70-degree water, it would take 33 minutes.

Draw efficiency is another crucial factor that is calculated as 70% of the overall storage capacity of the heater tank. As the hot water outflows, cold water enters the heater. So, for 50-gallon heater, 35 gallons are attributed as draw efficiency.

So next time when you want to assess the heating time taken by your shortlisted model, this guide will surely help you in this regard.