Determining the Right Size Water Heater for Your Home

It’s time to buy a new water heater, but there are so many different sizes and types of water heaters available. Which do you choose? A 40-gallon traditional tank? Or do you try a tankless heater? What about solar? And is there such thing as too big of a tank? These are some of the things you need to know to decide the right size and type of water heater for your home: the first hour rating, the energy factor, and the tank type.

First Hour Rating

The first hour rating is the measure of how many gallons of hot water your household uses in one busy hour each day. Consider your hour of peak water use per day. Is it in the morning, when everyone is busy making coffee, washing their faces, brushing their teeth, or even showering? Is it in the evening, when you water your plants after work, cook dinner, wash the dishes, and bathe the kids?
To determine the first hour rating (FHR), try this formula: maximum occupancy of your house plus one, multiplied by the number of gallons of hot water per person. This should equal your minimum FHR.
Let’s say you have a family of four and that each person uses 10 gallons of hot water a day. That means your family (plus one) times ten gallons of hot water per day makes a minimum of 50 FHR.
To put this in perspective, the EPA determined the average showerhead produces 2.5 gallons of water a minute. Showers, toilets, and faucets use up most of your hot water every day. The more people in your household, the more gallons of water you use.
The appliances your house uses are also something to consider. Do you have a large or jetted tub? Do you clean several loads of laundry a day? How many gallons of water per flush do your toilets use?
Once you determine your FHR, the next calculation you need to make is the energy factor.

Energy Factor

The energy factor (EF) is the efficiency of the water heater’s hot water production. In our example, you would want the highest EF rating for a tank with an FHR of 50. A contractor from ServiceWhale can help you calculate the energy factor rating your new hot water heater tank requires.
Remember, the higher the energy factor, the more efficient the water heater should be. You should use the heater’s energy factor, the first hour rating, and your water consumption calculations to determine what size and type of water heater you need.

Tank Type

Finally, you should also take into account the kind of tank you want to buy. Do you want a traditional, a solar, a heat-pump system or a tankless water heater?
A traditional tank can store a higher amount of water than the tankless system, but it is bulkier than some of the other options. A tankless system uses a gas burner or electricity to heat the water, but it needs a larger down payment and could run out of hot water for houses with a higher FHR. The right tank type depends on the space available and your own personal preferences.
Finding the Perfect Water Heater Size
ServiceWhale helps you find a contractor to manage your water heater concerns so you don’t have to worry about installing the right water heater for your home. Visit our blog and contact us for a contractor in your area, and to learn more about correct water heater size for your house.