Tank Style Water Heater Sizing Guide
A step-by-step guide to tank style water heater sizing.
Getting it Just Right
Tank Style Water Heater Sizing
Before you start shopping for a new tank style water heater, you’ll need to determine what size tank you need. This is a very important step! If you don’t size your water heater correctly, you’ll end up running out of hot water in the middle of your shower. In tank style water heaters, the tank holds water that is heated by electric elements or a gas pilot.
When you turn on your faucet, the hot water flows out of the tank to your fixture and is refilled with cold water when it empties out. It can take up to an hour to heat a fresh tank of cold water so if your tank doesn’t hold enough water for your hot shower, you are out of luck.
How Many Gallons is My Current Water Heater?
If you’re happy with the hot water supply from your current water heater, you can replace it with a new water heater that is the same size.
To find out how many gallons your tank currently holds, look for a sticker on the side of your water heater. It should have your serial number, model number, and other information about your water heater listed. You should be able to find the tank capacity in gallons on this sticker.
Pro-tip: If you currently have a 30 gallon gas water heater, you may actually want to replace it with a 40 gallon. Oddly enough, 30 gallon gas water heaters tend to be more expensive than 40 gallons.
How to Size Your Tank Style Water Heater
Installation Steps:
You’ll need to be sure your water heater can supply enough hot water for your household during it’s busiest hour for hot water usage. Think about your family’s daily routine and determine when your busiest hour is. It might be in the morning when two people take a shower back-to-back or it may be in the evening when you usually run the dishwasher and take a bath.
Use the chart to add up the total gallons of hot water your household will need during its peak hour.
For example, if you have 2 people take showers in the morning and you run a load of laundry, you’ll need 37 gallons of hot water (2 showers x 15 gallons + 1 load of laundry x 7 gallons = 37 gallons).
A water heater’s first hour rating (FHR) signifies the number of gallons of hot water the unit can provide in a single hour, starting with a full tank of hot water. You need to find a water heater with a FHR that is close to or above your peak hour demand. This will guarantee that your water heater can meet your household’s needs.
You can find FHR listed on most water heater packages if you are in a store. If you are shopping online, you may need to click through to the Specifications, Features, or Performance sections.
Unsure About Your Water Heater Sizing?
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Additional Resources
LEARN MORE ABOUT TANK STYLE WATER HEATERS
Preventative Maintenance for Your Tank Style Heater
Tank style water heaters have the shortest lifespan of all water heater types, but you can extend the life of your water heater with proper maintenance.
Tank Style Water Heater Sizing Guide
Before you start shopping for a new tank style water heater, you’ll need to determine what size tank you need. Learn how to identify what size will work best for your property.
Cost to Install or Replace Tank Style Water Heaters
Our master plumbers put together this page to help you understand the costs involved if you hire a licensed plumber for your project.
Common Tank Style Water Heater Problems
Learn about common tank style water heater problems and how to fix them. From leaking, to bad smells, to no hot water at all, some issues with your tank style water heater can be fixed easily.
Master Plumber's Guide to Tank Style Water Heaters
Explore essential tips, maintenance advice, and smart tech integration for tank-style water heaters.
Is it Time to Replace Your Hot Water Heater?
Your hot water heater is one of your hardest working appliances and it’s best to replace it before it stops functioning.