Shopping for a new water heater? Make sure the size is large enough to accommodate your family’s needs. We’ll show you how to find a water heater large enough so you won’t be left in the cold during a shower.

Step 1: Determine your peak hour demand

If your water heater can handle your biggest demands, it can handle your smaller demands at any other part of the day. We call that biggest demand time the “peak hour demand.” Here’s how you estimate your family’s peak hour demand:

  • Figure out which hour of the day your family uses the most hot water (Is everyone a morning person, or do you have people that shower at night when you’re using the dishwasher?).
  • Use this worksheet to estimate your maximum usage of hot water during this one hour of the day.

Voilà, you have your peak hour demand! Now you need to...

Step 2: Find a water heater’s first hour rating that’s close to your peak hour demand

A water heater’s first hour rating (FHR) is how much hot water it can provide per hour, assuming that it’s full of hot water. This combines how much water is stored in the water heater and how quickly it can heat cold water to the desired temperature (the recovery rate). Every modern water heater should list it’s peak hour demand at the top left of the EnergyGuide label. Here’s an example.

So, let’s say your peak hour demand is 70. You’ll want to get a water heater with a first hour rating of at least 68-72 gallons. Any less that that and you won’t have enough hot water. Any larger and you’ll be heating more water than you need, increasing your energy bills.

Get a new water heater for your Atlanta area home

Need help buying a water heater? If you need help finding the water heater size, type or brand you need, contact us for help. Ragsdale Heating, Air, Plumbing & Electrical has been serving the metro Atlanta area for over 25 years. Contact us online for more information on how we can help you.

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