What Size Water Heater Do I Need?

A reliable water heater is a necessary component in nearly every house today. If you’re planning to buy a new water heater or to update your old one, it can be a challenge to determine what size water heater you need. To ease the stress, let’s discuss some tips to help you determine what size best fits your needs.


How Do I Know What Size Water Heater Is Best for My House?


For starters, here are some numbers that show an estimate of necessary tank capacity in gallons based on the number of people in your house:


  • For 1 or 2 people—23 to 36 gallons
  • For 2 to 4 people—36 to 46 gallons
  • For 3 to 5 people—46 to 56 gallons
  • For 5 or more people—over 56 gallons


If we talk about an average family of four, a 40-gallon water heater can easily get the job done. However, needs vary from family to family, so you shouldn’t completely solely rely on these measurements. You can get a more accurate sense of your family’s hot water needs by digging a little deeper and determining what size water heater truly fits your needs.


In addition to the tank capacity, you need to consider the water heater’s first-hour rating when choosing a size. The first-hour rating, abbreviated as FHR, describes how much hot water can be produced by the tank in an hour when it’s fully heated. This figure is a reflection of the appliance’s efficiency i.e., how quickly it can reheat the water. Considering this fact will give you an idea of what your potential tank can handle at a peak hour of usage.


To efficiently meet all your family’s hot water needs, you need to look for a water heater with an FHR that meets or exceeds the number of gallons of hot water needed during the peak hour of usage.


Here are some numbers to help you estimate peak hour usage and determine the ideal FHR for your household:


  • Bathing or showering (per person)—20 gallons
  • Washing hair (per person)—6 gallons
  • Washing hands (per person)—2 gallons
  • Washing dishes by hand—6 gallons
  • Shaving—3 gallons
  • Running dishwasher—14 gallons
  • Running clothes washer—30 gallons


If you find it challenging measuring these things on your own, you can talk to a licensed plumbing expert in your area for advice. You can also get free estimates for your project.


Space Requirements Based on Size of Heaters


Tankless water heaters do not require as much space since they have a smaller storage tank. They can also be mounted to fit in tighter areas.  Since a 50-gallon tank-style water heater can be as big as six feet high and 22 inches in diameter, tankless water heaters are a better option if you have limited space.


Before you buy a tankless water heater, estimate the necessary flow rate based on hot water usage and the required change in temperature. Here is a list of typical flow rates (per fixture) in gallons-per-minute (gpm) to calculate the maximum amount of hot water you would use at once:


  • Sink faucet—1 GPM
  • Bathtub—3 GPM
  • Shower—2.5 GPM
  • Dishwasher—3 GPM
  • Clothes washer—3 GPM


Contact a Reliable Plumber to Discuss Your Water Heater Options


If you want to discuss the right options for your tankless water heater, it’s essential to speak with a professional plumber. Contact a reliable local company to discuss your options for a tankless water heater in Los Angeles.