What Size Tankless Water Heater Do You Need? Tankless Water Heater Guide

Are you tired of running out of hot water when you need it the most? Upgrading to a tankless water heater could be the perfect solution for your household. But before you make the switch, it’s important to find the right size for your needs. In this guide, we’ll simplify the process, helping you understand key factors that will impact your choice: water usage, flow rate, and temperature rise. By the end of this guide, you’ll have the knowledge to pick the perfect tankless water heater for your home.

How to Size a Tankless Water Heater

If you’re in the market for a long-lasting and energy-efficient water heater, atankless water heater may be the best option. But before you make the switch, whether looking toreplace an existing water heater or simply buying a new one, it’s important to find the perfect size for your everyday needs. An undersized unit will leave you without enough hot water, while an oversized one can lead to wasted energy and higher costs. Let’s get into some of the main factors to consider.

Flow Rate (GPM – Gallons Per Minute)

The flow rate measures how much hot water your tankless water heater needs to provide at any given time. It is measured in gallons per minute (GPM). To calculate the right flow rate for your household, you need to factor in the various fixtures and appliances that use hot water at the same time.

Here’s aquick reference for common household fixtures:

• Shower: 2.5 GPM
• Kitchen faucet: 1.5 GPM
• Dishwasher: 3 GPM
• Washing machine: 4 GPM

By adding the GPM of each fixture you plan to use simultaneously, you can determine the total flow rate your tankless water heater needs to support. For instance, if you expect to run your shower, kitchen faucet, and dishwasher at the same time, you’ll need a tankless water heater that can handle a flow rate of at least 7 GPM. Keep in mind that not all appliances of the same type have the same GPM, but there areEPA-mandated laws that make sure your appliances don’t exceed an unreasonable GPM. Choosing a tankless water heater that cooperates with the flow rate of your household will ensure a consistent supply of hot water for your everyday needs.

What is Temperature Rise for Tankless Water Heaters?

Temperature rise is the difference between the temperature of the incoming water and the desired temperature of the output. Most households need hot water around 120°F for their appliances and fixtures, but the incoming groundwater is much colder. Homeowners need to calculate their temperature rise to know how hard their water heater needs to work to reach the desired temperature; usually, the harder your water heater has to work, the lower its flow rate will be.

The temperature of the incoming cold water can vary significantlydepending on your location. Typically, states in the South receive warmer incoming water, while states farther North receive colder water. To calculate the temperature rise, subtract the incoming water temperature from your desired output temperature:

Temperature Rise = Desired Output Temperature − Incoming Water Temperature

Correctly finding the temperature rise, based on your area and chosen output temperature, is essential in picking a water heater that can heat your incoming water quickly and efficiently so that you don’t have to deal with anyunexpected cold showers.

Step-by-Step Guide to Sizing Your Tankless Water Heater

Now that you are aware of the key terms you need to be aware of, let’s walk through the steps of sizing your tankless water heater properly:

1. Determine Peak Hot Water Demand: Make a list of all the hot water appliances and fixtures you expect to use simultaneously. Add their GPM values together to find the maximum total flow rate required for your home and look for a water heater that either matches or exceeds that number.
2. Calculate Temperature Rise: Find out the average temperature of your incoming water and subtract it from your desired hot water temperature. The most common hot water temperature is 120°F, but if you find you need hotter water, make sure to factor that into your calculation.
3. Energy Efficiency: Look for models withhigh energy efficiency ratings. Although they might be more expensive upfront, they can save you money in the long run by lowering your energy bills.
4. Fuel Type: Tankless water heaters can be powered byelectricity, natural gas, or propane. Electric water heaters usually cost less to install, but their monthly costs may be higher since electricity is pricier than natural gas and propane in most areas. It’s also important to consider the availability of power sources in your area.
5. Warranty and Support: Check the warranty and support options provided by the manufacturer. A good warranty can provide peace of mind and protect your investment.
6. Maintenance Needs: Regular maintenance is essential to keep your tankless water heater running efficiently. Shop for units that are easy to maintain or come with good service agreements.
7. Warranty and Support: Check the warranty and support options provided by the manufacturer. A good warranty can provide peace of mind and protect your investment.
8. Select the Right Unit: Once you calculate both the total GPM and temperature rise for your household and take into account the factors listed above, you can select the right unit for your needs.

As with any major home appliance, it’s important to do your research and carefully consider all factors before making a decision on which tankless water heater is best for your household. If you still need help picking the right unit, consider contacting aprofessional plumber. They can help you accurately determine your hot water demand and calculate the appropriate temperature rise to find the perfect tankless water heater for your home.

Common Mistakes to Avoid

There are several common pitfalls homeowners fall into when choosing a tankless water heater. Avoid these mistakes to ensure you get the best unit for your needs:

1. Underestimating Flow Rate Needs: If you don’t properly account for each appliance that may need hot water at the same time, your new water heater won’t be able to heat enough water for your needs. Be realistic about your peak demand.
2. Ignoring Temperature Rise: Failing to consider temperature rise can result in a unit that doesn’t heat water well, especially in colder climates. If you notice your shower
3. Overestimating Size Requirements: While it’s important to avoid undersizing your water heater, oversizing can also be a problem. It can lead to unnecessary energy usage and higher costs overall.
4. Not Accounting for Installation Space: Measure the available space in your home before purchasing a tankless water heater. Some units may require additional clearance or venting, so it’s important to factor in these considerations when making your selection.
5. Choosing Based on Price Alone: While cost is certainly an important factor, don’t make the mistake of solely basing your decision on price. A cheaper unit may not have all the features you need and could end up costing you more in the long run due to higher energy usage or frequent repairs.

By following this advice, you can avoid unneeded expenses and make sure you select the best tankless water heater.

Contact Nearby Plumbing for Tankless Water Heater Sizing Help

Hopefully, this guide has shed some light on the importance of properly sizing your tankless water heater. If you’re still unsure or have any questions, don’t hesitate to reach out to a professional for assistance. At Nearby Plumbing, our team of experts can guide you through the process and help you find the perfect tankless water heater for your home. We also offerinstallation and maintenance services to make sure your tankless water heater runs efficiently for years to come.Contact us today for more information!