What Size Water Heater Do You Need? Here's The Answer
Choosing the Right Water Heater Size:
Imagine running out of hot water during a shower on a cold morning. We’ve all been there, and it’s not pleasant. Luckily, for most of us, the dreaded cold morning shower is a preventable problem—even if you like to prepare for your workday with thirty minutes under the steam.
Choosing the right size water heater for your home and water usage habits can help prevent those awkward moments when the water suddenly goes cold. Many people do not know how to choose the best size water heater for their home, so they rely on the water heater that was installed when they purchased their home, or they choose one based on the size of the space available.
Although choosing a water heater can seem like a confusing process, by the end of this article you will know exactly what size water heater you need.
Understanding Water Heater Sizes:
The term “water heater size” simply refers to the quantity of hot water the heater can provide within a set time. For tank-style heaters, this is generally measured in gallons, whereas tankless heaters measure their flow rate in gallons per minute.
To understand how many gallons of water you will need heated at one time, consider your peak water usage, or the time of day when you use the most water. If you tend to run out of hot water in the evening, when it’s bath time, you’ve run the dishwasher, and you’ve got a load of laundry in the wash, this will be your peak usage time.
If you have a family getting ready in the morning and you’re out of hot water after the last shower—never mind setting up the dishwasher for after breakfast—then morning would be your peak water usage time.
To calculate the size of water heater you need for your home, you will want to look at the tasks that you usually do during your peak usage and add up the estimated water consumption of those tasks. Once you have determined what you’re using all your water for, you can use a worksheet, like this one by the Department of Energy, to determine your true peak hour demand.
Once you have determined your peak hour demand, you will want to choose a water heater that has a first hour rating or tank size that matches your peak water usage. If your peak hour demand is an odd number, or doesn’t match any water heaters you can find, you will want to choose a water heater that is slightly larger.
If you choose a water heater that is too small, you will run out of hot water during high demand. However, you should be careful not to choose a water heater that is significantly larger than your peak demand, as this can cause energy waste and increase your power bills.
Factors Determining the Right Size for Your Water Heater
There are many factors that affect your peak hour demand. This includes your household size, as the more people are using water, the faster your hot water will run out.
Another is the type of appliances you have; top-loader washers use more hot water than horizontal axis washing machines. In fact, while a front-load washer uses an average of 15 gallons of water per load of laundry, a top-load washer uses 25 gallons.
Showering versus bathing is another habit that can affect your water usage, as showers use an average of 20 gallons of hot water, whereas baths can use up to 140 gallons.
Water Heater Sizing Guide for Different Households:
For Singles or Couples (1-2 bedrooms):
Imagine it's just you and your partner. Morning routines are simple: maybe two showers, a load of laundry a couple of times a week, and occasional dishwashing. Since the peak hour demand is low, you would likely need a small water heater, between 30-40 gallons.
For Small Families (2-3 bedrooms):
On the other hand, if you’ve got a larger family, maybe one or two kids, and your morning routine looks a little more like chaos, you will need a larger water heater. Imagine multiple overlapping showers, breakfast for four, and a load of laundry so the kids can be prepared for their sporting events that evening. Sound like you? In this scenario, you would need a medium-sized water heater, around 40-50 gallons.
For Larger Families (3+ bedrooms)
Or maybe your family is larger, and your morning looks more like two teenagers who love long showers, multiple loads of laundry for your younger child’s gymnastics meet and your middle child’s karate championship, and a dishwasher that seems to run non-stop. In this case, you’re going to be looking for a large water heater.
A good estimate for 5 people is around 55 gallons—for each person in the home over that, you can add an additional 10 gallons to your estimate.
Tankless vs. Tank Water Heaters
Storage tank water heaters are the most common type of water heater, but tankless water heaters have been increasing in popularity due to the fact that they are more efficient than storage tank heaters, as well as their smaller size. For those who are used to a storage tank water heater, tankless water heaters may have a learning curve.
While storage tank water heaters have water readily available and at the right temperature on demand, tankless water heaters heat the water that is coming into your home. This means that when the ground is colder, it may take longer for your water to reach a comfortable temperature.
Additionally, tankless heaters usually have a higher up-front cost than a storage tank heater and may require you to upgrade your home’s electrical service. This can mean that, even though tankless water heaters run more efficiently, storage tank water heaters can still be a better choice depending on your needs and where you live.
Tips for Maximizing Water Heater Efficiency
After purchasing a new water heater, you will want to practice preventative maintenance in order to protect your investment. First, check around your water heater regularly to ensure you do not notice any leaks or wet patches.
If you experience anything odd with your hot water, such as suddenly running out of hot water way earlier than you normally do, you will likely want to call a service technician to inspect your hot water heater and ensure there is no sediment build up and make sure the heating elements are still functioning properly. You will also want to plan regular maintenance for your water heater.
If you live in an area where you have hard water, you will need to have your tank serviced more often than in areas without, but a good rule of thumb is once a year. Many water heater brands require regular professional service to maintain the warranty.
Frequently Asked Questions About Water Heater Size
I'm considering switching to a tankless water heater. How does size factor into my decision?
Switching to a tankless water heater can be a good choice for many people. However, depending on the size of the tankless water heater, you may need to upgrade your home’s breakers in order to have one installed.
How does the lifespan of my water heater relate to its size?
If your hot water heater is too small for your home, it will be working harder than it should need to and will often fail before it reaches its expected lifespan. If your water heater is the correct size for your family, the size will not affect the lifespan.
I live in a hard water area. Does this impact the size of the water heater I should choose?
This does not affect the size of water heater you should choose. Living in an area with hard water does affect how often you should have your hot water heater serviced in order to ensure the best performance and lifespan.
Choosing The Right Water Heater Size
It’s important to choose the correct size water heater for your home for comfort, energy efficiency, and longevity. By investigating your household’s hot water consumption, you will be prepared to find the right size water heater.
If you are in the Chattanooga area and have outstanding questions about choosing the best size water heater without sacrificing energy efficiency, the EPB Energy ProsSM are here to help. Schedule an in-person analysis of your home or a thirty-minute phone call to have all your questions answered by clicking this link or by calling 423-648-1372.
