There are many things to consider when you are choosing a water heater for your home. You want to make sure the appliance is capable of maintaining your hot water needs for every spigot. Capacity and size are your first concerns when looking at your water heater.


First, you must find out what capacity your water heater has. Capacity factors in the size of the storage tank and how quickly your tank can heat, also known as its recovery time.

Storage tank size

Storage tank size can range from 20-120 gallons, usually 40-80 gallons, unless it is a shorter low-boy model. You have to understand your family’s needs, a too small tank will run out of hot water too quickly, but if you get one that is too big, you will be paying way too much to keep your full tank heated.

Recovery time

Recovery time can be found by checking the FHR number (first-hour rating). This number can be found on a label on the tank. Your FHR needs are dependent on how many bathrooms and occupants are in your home, whether you have a gas-powered water heater or an electric water heater.

Rating either type of storage water heaters is contingent on how many gallons they can raise, in one hour, to 90 degrees Fahrenheit.


Gas units can recover more than a full tank in an hour. For gas-powered water heaters, recovery time is dependent on overall efficiency and the BTU input. Input on a 30-gallon unit is about 32,000, to up to 88,000 BTUs for a 100-gallon tank. The recovery time is faster on an efficient water heater with higher BTU input.


Electric heaters are usually rated 20-25 gallons per hour. Electric water heater elements usually range between one 5,500-watt element or two 4,500-watt elements. The two lower-kilowatt elements work better in cohesion than the one higher-wattage element, heating your water much faster.

Measuring your family’s needs

Measuring your family’s needs can be measured by determining both the number of bathrooms in your home and the number and ages of its occupants. For instance, a family with smaller children would need a larger water heater than a family with three adults, because families tend to need more laundry done with smaller children.

Obviously, the number of bathrooms factors in. A one-bathroom home should have either a 30 or 40 gallon tank, while more bathrooms would mean larger tanks. Also, for three or more bathrooms, be aware of whether you are getting a gas tank or an electric, an electric water heater will take longer to heat so you would need a larger tank.

Capacity and Size When Choosing A Water Heater