The size of water heater you need will depend largely on the number of people who live in your home and the number of bathrooms you have to accommodate them. Usually, the smallest available water heater is 20 gallons, while the largest can be 80 gallons or more. The idea is to pick a water heater that’s neither too small, in which case it will wear out too quickly, nor too large, which will raise your energy bill unnecessarily.
How to Pick the Right Size
In most cases, a 20-gallon tank is just too small in the 21st century. The smallest tank that’s usually recommended is 40 gallons, which will suffice for one or two people. For three people, a 60-gallon tank is usually enough. For six or more people, especially with three or more bathrooms, an 80-gallon tank would be the minimum. Above six people, the formula is 10 gallons per extra person past 80 gallons.
The “first-hour rating” (FHR) is also an important consideration. FHR shows how much hot water the heated tank can produce in the space of an hour. It’s usual to pick a tank with an FHR that’s roughly double its capacity. Such a rating takes into account the tank’s ability to heat cool water that replaces the already-heated water in the tank as someone showers, washes dishes, or performs other activities that use hot water.
Here are a few common uses of hot water and the number of gallons required for each:
- Toilet flush: 2 gallons
- Hand washing: 2 gallons
- Shaving: 3 gallons per person
- Brushing teeth: 3 gallons per person
- Dishes by hand: 6 gallons
- Dishwasher: 14 gallons per load
- Shower: 20 gallons per person
- Laundry: 30 gallons per load
Toilets that predate 1950, depending on the brand, will use up to 7 gallons per flush.
A family of five who showers every day, does three loads of laundry, a full dishwasher, and practices good oral hygiene can easily go through 300 or more gallons of water every day. Bigger families might need multiple water heaters.
Other Things to Think About
Water heaters that have tanks come in two varieties: electric and gas-powered. Which will you select? Then, you also have the option of choosing a tankless water heater. The advantage of tankless water heaters is that they use at least 30% less energy to heat the water because they don’t have to heat an entire tank at once. Their disadvantage is that their initial cost is much more expensive than water heaters with tanks. To figure out which tankless water heater you might need, count a flow rate of 2 gallons per minute per person in the home.
The Benjamin Franklin Advantage
Our history goes back nearly 40 years at Benjamin Franklin Plumbing, so we’ve got the necessary experience to advise you wisely regarding water heaters. Give us a call today to book an appointment.