How to Determine the Ideal Water Heater Size for Your Home

A home’s water heater is one of the most important appliances, providing hot water for many different essential household activities including bathing, laundry, and washing dishes. Having the right water heater size a critical because, if sized incorrectly, you could run out of hot water when you need it most. If you’ve ever lived or stayed in a home where the hot water runs out while you are right in the middle of a shower, you know just how frustrating it can be. And, if your water heater is too large, it will not run efficiently and may lead to increased utility costs and a diminished water heater lifespan. 

Often, when homeowners are debating between water heater sizes, they are tempted to size up and may oversize their water heater in an attempt to avoid running out of hot water. And, though the instinct is certainly understandable, an oversized water heater is not necessarily ideal. Complicating matters further when choosing an ideal size is that sizing and efficiency differ between water heaters depending on whether they are gas or electric and whether they are tankless or have tanks. 

Additionally, how many people live in your home and your overall average hot water usage will be important factors in determining size. Bob Vila has a helpful chart that breaks down average hot water usage based on the number of occupants in a home:

You can estimate the necessary tank capacity (in gallons) based on the number of people in the house:

• 1 or 2 people—23 to 36 gallons
• 2 to 4 people—36 to 46 gallons
• 3 to 5 people—46 to 56 gallons
• 5 or more people—over 56 gallons (add 10 gallons per additional person)

But, as aforementioned, the number of occupants in your home is not the only consideration, average use, and lifestyle should also be factored in. If your home’s occupants take a lot of showers every day, or you do a ton of laundry or dishes, you may need more hot water than the average. When determining an ideal water heater size for your home, consult an experienced plumber who can help guide you toward an ideal size that allows your home to remain energy efficient without ever running out of hot water.