How To Size Your Water Heater: Do It Right The First Time

If you’re in the market for a new water heater for your Middletown-area home, knowing how to size your water heater will help you get the best return for your investment. What size water heater you need depends on the type of water heater, the number of people in your family and your family’s usage habits. Buying too big means you’re wasting money on the cost of the water heater and the energy to heat the water. Buying too small means you’ll run out of hot water when you need it. If you size your water heater correctly, you’ll save money and your water heater will run more efficiently.

If you’re buying the traditional type of water heater that stores water and keeps it hot until you need it, you can size your water heater by figuring out your peak hour demand. A storage water heater usually tells you its capacity during the first hour of use, called the first hour rating. This information is on the yellow and black EnergyGuide label and in the manufacturer’s product literature. By estimating how many gallons of water your family uses during the hour of highest use, you can determine which water heater has a first hour rating that fits your peak usage.

Here are some guidelines for water usage:

• Taking a shower: 10 gallons
• Using a washing machine: 7 gallons
• Using an automatic dishwasher: 6 gallons
• Washing dishes by hand or preparing food: 2 gallons per minute
• Shaving: 0.5 gallons per minute

If you have an on-demand or tankless water heater, you’ll need to figure out the temperature rise and the flow rate that you’ll need when it is in use. To find your flow rate, add the flow rate of each water device you expect to use at one time (faucets, dishwasher, etc.). To find your temperature rise, subtract your incoming water temperature (probably 50 degrees) from your desired output temperature.

For more information on how to size your water heater, contact C.R. Wolfe Heating & Air Conditioning. We’ve proudly served Middletown and the surrounding area since 1945.

Our goal is to help educate our customers in Middletown, New York about energy and home comfort issues (specific to HVAC systems).  For more information about water heaters and other HVAC topics, download our free Home Comfort Resource guide.

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