In our modern world, sometimes we forget to appreciate how luxurious it is to take a hot shower. Running hot water provides comfort and allows you to carry out important tasks around the house more effectively. Hot water is essential in the kitchen, the laundry room, and the bathroom. Choosing an appropriately-sized water heater for your home will ensure your family has enough hot water available every time it is needed.

Considerations When Choosing a New Water Heater

Water heaters provide a consistent stream of hot water to several water fixtures throughout your home. It is a central appliance that is one of the most important components of your home’s function and flow. Although the design of water heaters is relatively simple, there are multiple types available on the market.

There are four main types of water heaters, including:

  • Tankless
  • Storage and heat pump with tank
  • Solar water heating system
  • Condensing water heating system

A professional contractor that specializes in plumbing installations will be able to provide a comprehensive consultation to help you select the water heating system that is most compatible with your home. For practical purposes, we will mostly discuss the storage and heat pump with a tank system, which is most commonly found in residential homes.

Undersizing Your Water Heater

If you select a water heater that is too small, you will quickly run out of water when showering, washing dishes, doing laundry, etc. A household of five people typically requires a tank that holds approximately 50 to 80 gallons of water.

Oversizing Your Water Heater

Installing a water heater that has a higher capacity than you need will increase your expenses. For instance, a 60-gallon heater for a household of two people is excessive. A 20-gallon heater is more appropriate in this case.

Average Water Usage

Determining your average water usage is part of how you make your decision regarding what size of hot water tank you need. Keep in mind these three factors:

Fuel Source

Which type of fuel will you be using? Options include electricity, natural gas, or liquid propane. You also have to determine if you’ll be connecting the water heater to your boiler system.

Physical Size

You have to determine the location of a dedicated space where the water heater will be installed. It needs to be a spot that is easily accessible for maintenance. You can also build a utility closet into the wall with an access door for servicing.

Size of Your Household

The size of your household has a major impact on your decision. A two-bedroom condo has much smaller needs compared to a large five-bedroom home. Also, the number of people living in the home makes a significant difference. The last thing you want is for a family member to take a shower and be left with only cold water.

Appliances in the home, like the laundry machine and the dishwasher, must also be considered if they will be used at the same time as when your family is showering.

For a storage-tank water heater, this is the general guideline to follow:

  • 1-2 people: 30-gallon capacity
  • 2-3 people: 40-gallon capacity
  • 3-4 people: 50-gallon capacity (electric) or 40-gallon capacity (natural gas or liquid propane)
  • 5 or more people: 80-gallon capacity (electric) or 50-gallon capacity (natural gas or liquid propane)

Water heaters that work with a storage tank are sized according to a BTU (input and capacity in gallons) value. If your home demands a large amount of hot water regularly, you will need a higher BTU value.

Water Usage Habits

One consideration to think about when you’re shopping for a new water heater is the number of people in your home and their shower habits. Some people may only take a 10-minute shower, while others can be in the shower for as long as 40 minutes or more. You also have to think about the time of day people shower. Do multiple people shower back-to-back at the same time of day? Also, besides showering, ask yourself what other activities around the home require hot water at the same time.

If your home has four people who each take a 10-minute shower within one hour, you will likely need approximately 40 gallons of available hot water. This alone can empty the tank pretty quickly, leaving the rest of the home without hot water.

For homes that have a tankless heater, choosing the right size heater will be a bit different. Tankless water heaters are not able to store hot water, which means their capacity doesn’t come into play. However, you do have to consider the flow rate of hot water and its temperature.

Water Heater Flow Rate

When it comes time to purchase a new hot water heater, you have to determine the flow rate your household requires. Additionally, you have to come up with the sum of the flow rates required by all the appliances that can potentially be functioning at the same time. The required temperature rise can then be determined by taking the desired out-flowing water temperature and subtracting the in-flowing temperature.

The temperature of groundwater varies in different regions of the country and during different seasons of the year. For example, if you live in an area whose in-flowing ground water temperature is 50 degrees Fahrenheit during the summer season and your desired out-flowing water temperature is 100 degrees, then you will need your tankless water heater to have a temperature rise of 50 degrees.

First-Hour Rating

Regarding water heaters that use tanks as part of their design, you must consider a water heater’s first-hour rating (FHR). This rating defines the amount of hot water that a tank can generate in one hour when fully heated. This measurement represents the efficiency of a water heater’s capacity to reheat water.

This formula allows you to get an idea of the performance capacity of your water heater during one peak hour. In other words, if a 50-gallon water heater has an FHR of 90 gallons, in one hour, it can supply up to 90 gallons of hot water. Therefore, you need a water heater with an FHR that reaches or exceeds the number of gallons of hot water required for all activities occurring at the same time during the most demanding period of the day.

The numbers below can help you estimate peak hour usage to find out your ideal FHR.

  • Showering or bathing: 20 gallons/person
  • Washing hair: 6 gallons/person
  • Washing hands: 2 gallons/person
  • Hand-washing dishes: 6 gallons
  • Shaving: 3 gallons
  • Running dishwasher: 14 gallons
  • Running clothes washer: 30 gallons

Making a Smart Decision

At Home Service Heroes, we are dedicated to helping homeowners enjoy the best water heater systems in Tampa and its surrounding areas. In addition to water heaters, we also provide electrical, heating, cooling, plumbing, and indoor air quality services. We are proud winners of multiple awards, including Small Business of the Year, Angie’s List Super Service Award, and Company of the Year Award, and were inducted into the 2007 Home Service Hall of Fame. Our clients continue to provide referrals and high ratings for the quality of service we provide. To begin the process of selecting a new water heater for your home, call the expert team at Home Service Heroes today.


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