What Size Tankless Water Heater Do I Need in 2022 – Complete Guide

Do you want to know what size tankless water heater do I need in 2022? From residential to commercial and small to large homes, the demand for water heaters varies. It may be water usage peak or frequency that may affect the requirements. Therefore, what size water heater I need is a very hot question to explore here. You know, no one likes to stick with one type of product for all time. Talented brands understand this fact and work accordingly.

The introduction of tankless water heaters is also the result of this behavior. Now, the trend is intensely moving towards the insight of tankless vs. tank water heater calculators. To make this consideration into account, we are going to discuss the expected size of the water heater that you need within the upcoming seconds.

Required Size For Tankless Water Heater

Generally speaking, what size tankless water heater do I need in 2022, the capacity varies from 30 to 80 gallons, or you might say that it stands for 1 to 5 people or more. This is just a rough estimate that we have brought into your consideration, but the fact remains that this calculation can also be altered according to the situation that we might find ourselves in. 

The main reason behind making this type of estimation is that the unit becomes expensive as with the size. So, knowing a perfect size that suits your requirements and specifications is more important.

Sizing Tank Water Heater

No one wants to compromise over the what size tankless water heater do I need as it is the foundation of hot water capacity. On the opposite side, getting the smaller unit might affect other features. Find these two points and get the unit with the required capacity.

1- First-Hour Rating

The first-hour rating or the acronym for it is FHR. This FHR is the unique quantity of water that the water heater can produce during the first hour of operations. But, right after some time, the temperature starts to get on the lower side. The frequency for cooling water in the tank relies on water usage. One should keep that in mind that every water heater comes with a unique characteristic, and that is of time. The time is taken by the water to reach its maximum FHR. Thus it is concluded that the consideration of time is an essential element that must be kept in mind that it requires to meet the water need.

2- Peak Hour Time

The demand for water required for usage varies during the time of the day. Hot water required in the morning is totally different from the water required during the noon or even in the evening. Although water consumption remains a part of every household.

According to research, when we shower in the morning or the evening, we consume more water when compared with the water being consumed during laundry or even during dishwashing. Whenever 2-3 persons taking a shower during a short span of time eventually ends up in hot water.

Furthermore, showing the time and frequency of water being consumed during a week also matters a lot. Let me share my personal information. Water consumption also varies among gender. My daughter takes roughly 30-40 minutes to shower, while on the other hand, my son just takes 5-10 minutes on a daily basis.

According to this shared information, every household has different requirements for hot water. The water intensity and frequency may also be lower or higher. To come up with the conclusion, one must have these two parameters and estimates into their consideration regarding the water capacity they require.

In my personal opinion, every household needs to have 3 to 4 gallons of water with the same water demand as discussed above. If you have a large family, then I am pretty much sure that your consumption of hot water is good. On the other hand, the water demands have a close relation to the budget you have in mind.

Under this scenario, you must give yourself a favor while spending more time on selection.

Peak Hour Demand Estimation

There are two common methods that are considered for having a proper estimate regarding your peak hour demand.

1- Simple Calculations

The first method is to by calculating with simple calculators. In this method, you have to count the number of people living in your home. Do not forget to count in your daughter or son who is living in a hostel or out of the home. Let us consider that you have an overall population of 7 people living under the same roof. Further, you need is to multiply the number of people you have in your family and multiply with 12. 12 is the number of gallons required by each person on a daily basis.

2- Deep Calculations

This method is generally followed by professionals that calculate a near to accurate estimate. This estimate allows you to calculate peak hour demand for you. Further, this process leads to the calculation of the correct FHR value. This process can be elaborated in two steps which are elaborated below for your consideration.

Step 1 

The first step would be to observe keenly and pinpoint the time in which your family uses the highest quantity of water in one hour. Furthermore, it might be morning, evening, or noon that seeks the highest water quantity. While going for this estimation, you need to keep the number of people in consideration.

Step 2 

In the second step, you need to enlist the activities that your family members carry on within this one hour of highest usage. Don’t forget to mention the time it gets repeated. After multiplication with this number, all them all and find peak hour demand.

For example, showering needs 10 gallons of water per time, and your family runs 2 units at a time, then the final demand would be 20 gallons (10 x 2). 

On the other hand, washing hands demand 2 gallons of water 4 times in an hour, and then the final capacity would be 8 gallons (2 x 4). Finally, the overall demand would be (20 + 8) 28 gallons.

Below is the table that tells the estimated capacity for various home needs.

The shower needs 10 gallons per usage

Shaving needs 2 gallons per usage

Hands and face washing needs 4 gallons per usage

Hair shampoo demands 4 gallons per usage

Dishwashing needs 4 gallons per usage

Food preparation demands 4 gallons per usage

The automatic dishwasher needs 4 gallons per usage

Washing clothes need 7 gallons per usage.

Water heater requirements are based on the family members that are living within a household.

For a quick go, you can bypass the calculations and directly find the size based on family size.

1 to 2 members need 23 to 36 gallons

2 to 3 members need 36 to 46 gallons

3 to 4 members need 46 to 56 gallons

5 to 6 members need 56 to 80 gallons

6 to 7 members need 80 to 100 gallons

A typical family comes with the size of 5 to 6 members that are living in a house. For them, 56 to 80 gallons of water usage per day is considered ideal. At the same time, we are saying that it is just a rough estimate. The results may be different from calculations that come up in the end. 

Well, how can you say that the water demand is high?

That’s too simple. If you need multiple points of hot water, at the same time, you need a higher-capacity water heater in the first place. A bigger tank is good to go to meet the higher demands of a family living in a house of around 5-6 people. On the opposite side, with one or two supplies at a time, counting the number of people would be enough to consider.

Size estimation for tankless water heater

Size estimation for a tankless water heater demands different features to consider rather than a tank heater. In this type, two different features that we need to focus on for arriving at accurate and actual results. 

  1. Consider the flow rate that tells the required amount of hot water.
  2. Consider the difference between incoming groundwater temperature and required temperature.

Actually, you should know how many connections you do want at a time in your house. It is the flow rate of the water heater. For a large family, high water demand, and the cold climate, the flow rate should be higher. Furthermore, the tap water temperature gets affected by the groundwater temperature. You should know the difference between these two temperatures.

 This temperature difference is called temperature rise. In addition, you must have an idea about that this difference in temperatures should not be higher. This difference varies by locality, so you should know how to switch according to temperature.

Tankless Sizing Calculator

The following strategy is to go for the calculation to find the perfect size that is a must for a tankless water heater. For this calculation, try to consider the maximum number of fixtures.

1- Estimate Flow Rate

Out of the heaviest flow rate for all the expected results. For instance, you use two standard showers, a washing machine, a dishwasher, and two faucets at a time. Finally, the final flow rate results out to be (4 + 1 + 2.5 + 2) 9.5 GPM. 

A standard shower us 2 GPM

Rain type shower use 5 GPM

Body spray per nozzle use 2 GPM

Dishwasher use 0.5 to 1.5 GPM

A standard dishwasher uses 2.5 GPM

The faucet uses 1 GPM

A high-efficiency washing machine uses 1 GPM

The standard washing machine uses 2.5 GPM

2- Locate Groundwater Temperature

For the perfect calculation of groundwater temperature, you are required to check the groundwater in your location. The first thing with which you can better results is the use of the map. The map is the perfect source that provides you with the groundwater temperature in your specific area where you are currently living.

3- Calculate Temperature

The third and last step is calculating the temperature. To calculate the temperature, you must know the exact output for the temperature to arrive at the required increase that can accurately meet the demand that you have set in your mind.

Frequently Asked Questions

What size tankless water heater do I need to replace a 50-gallon water heater?

Within the USA’s south location, you need to exchange a 50-gallon water heater with a gas tankless water heater with a capacity of 10 gallons per minute. Furthermore, for the electric tankless water heater, the requirement for the combined capacity is 27 kilowatts. Now coming to the southern part, a gas tankless water heater with 7 gallons per minute would be enough for a normal household having 5-6 members. In addition, the electric heaters their strength must be 80-kilo watts.

What size of tankless water heater is needed for a family with 4 members?

For a family of a household that has 4 members, the quantity changes between 40 to 75 gallons. This variation in the requirements exists according to the peak usage of water.

For a family of 7 or more, what should be the capacity of a water heater?

For a family having members more than or equal to 7 members, the estimated capacity required to meet the requirements is 100 gallons, or that could be more.

Conclusion

This is the time to wrap the article up. We have given you enough insight to find what size tankless water heater do I need in 2022 that meets your demand. Finding this quantity is not tricky but quite tricky. 

We have discussed two methods that include both simple and calculated. No doubt, the calculations are not complicated, but most non-professionals prefer to stick with the simple methods.

Getting the tankless water heater with a storage tank also demands the same procedure to follow. All the water heaters are very versatile and equipped with the latest technology to further support. 


Share post on


BESTHEATERGUIDE.COM is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

How to Wire a Tankless Water Heater in 2022 – Complete Guide Tankless heater info

How to Wire a Tankless Water Heater in 2022 – Complete Guide

How to Wire a Tankless Water Heater in 2022 is a crucial question as...

By Emma Johnson
Tankless heater info

How much propane does a tankless water heater use in 2022 – Complete Guide

Are you confused as to why your tankless water heater keeps consuming huge amounts...

By Emma Johnson
How does a tankless water heater work in 2022-  Complete Guide Tankless heater info

How does a tankless water heater work in 2022- Complete Guide

Although tank water heaters are still the most commonly used machines for heating up...

By Emma Johnson
What is the downside of a tankless water heater in 2022 – Complete Guide Tankless heater info

What is the downside of a tankless water heater in 2022 – Complete Guide

Are you willing to know what is the downside of a tankless water heater?...

By Emma Johnson
who makes the best tankless water heater in 2022 – Complete Guide Tankless heater info

who makes the best tankless water heater in 2022 – Complete Guide

The answer to this question is ambiguous. Because all tankless water heater brands compete...

By Emma Johnson
How to reset tankless water heater in 2022 – Complete Guide Tankless heater info

How to reset tankless water heater in 2022 – Complete Guide

You may have instances where you had a problem and called a plumber. The...

By Emma Johnson
Are electric tankless water heaters efficient in 2022? – Complete Guide Tankless heater info

Are electric tankless water heaters efficient in 2022? – Complete Guide

Whenever do we ask ourselves how can one decide whether an electric tankless water...

By Emma Johnson
Are Tankless Water Heaters Worth the money in 2022 – Complete Guide Tankless heater info

Are Tankless Water Heaters Worth the money in 2022 – Complete Guide

Are the tankless water heaters worth the money in 2022? The answer is yes...

By Emma Johnson

Latest Posts

Best Natural gas tankless water heater in 2022 – Reviews & Buyer Guide Tankless heater reviews

Best Natural gas tankless water heater in 2022 – Reviews & Buyer Guide

No matter what part of the world you live in, one of the main...

By Emma Johnson
Best space heater low energy in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best space heater low energy in 2022 – Reviews & Buyer Guide

A space heater is a common appliance seen in homes, offices, and workplaces in...

By Emma Johnson
Best space heater for garage in 2022 – Reviews & Buyer Guide Space Heater Reviews

Best space heater for garage in 2022 – Reviews & Buyer Guide

Winter is about to be at your doorstep. Are you ready to fight with...

By Emma Johnson
Best space heaters consumer reports in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best space heaters consumer reports in 2022 – Reviews & Buyer Guide

After hearing the footsteps of winter, your very next step is to find the...

By Emma Johnson
Best space heater brands in 2022 | Reviews & Buyer Guide Tankless Heater Brands

Best space heater brands in 2022 | Reviews & Buyer Guide

A space heater is a need for today's luxurious homes. Winter is especially incomplete...

By Emma Johnson
Best space heater for basement in 2022 – Reviews & Buyer Guide Space Heater Reviews

Best space heater for basement in 2022 – Reviews & Buyer Guide

The best space heater for basement has an intense cry all around. This is...

By Emma Johnson
Best tankless water heater for Condo in 2022 – Reviews & Buyer Guide Tankless heater reviews

Best tankless water heater for Condo in 2022 – Reviews & Buyer Guide

Traditional water heaters are far more frequent in homes, but tankless water heaters have...

By Emma Johnson
Best Point of use tankless water heater in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best Point of use tankless water heater in 2022 – Reviews & Buyer Guide

A Point-of-Use tankless water heater is a water heater that is designed to provide...

By Emma Johnson