How to choose a tankless water heater is a decision that stays with you for a long time. A tankless water heater that is excellent for others may not be so for you. To help you make a decision, we have created a checklist that can help you decide which tankless water you should buy.
Let’s discuss some fectors for choosing a tankless water heater
1. Brand Selection
It is one of the most crucial factors when deciding on a tankless water heater. You should not select the brand of tankless water heater based on word of mouth or hearsay. It is imperative that you also check:
- The warranty duration
- Do they have a local service provider,
- In addition, how reliable are they?
Will they leave you hanging after selling you the unit or not? It would help if you were clear on these things should you select your tankless water heater brand.
2. Incoming Water Temperature
Another thing that can come in the middle of you and your hot water is the water temperature in your area. A tankless unit with a specific capacity working well for a person in warmer regions may not be suitable for you who lives in a colder region. This is because the increase in temperature that the tankless water heater has to bring is different.
A tankless unit with a capacity of 3 gallons per minute could bring a water temperature from 60°-120° in less than one minute; hence, you get total capacity. However, if the same tankless unit has to bring water temperature from 30°-120°, it will take much more time. Hence, you can only get 2.5 gallons per minute of capacity.
Therefore, if you live in a colder region, you should go for a little higher capacity tankless unit than your needs.
3. Tankless Capacity
Each tankless water heater comes with a specific capacity of water it can heat at a time. Therefore, you need to decide how big of a tankless unit you need to buy to meet your needs.
But before that, you need to estimate how much hot water you need at a time. There are two ways to estimate your hot water needs; you can use the following chart to estimate or check them manually using a bucket. You can measure the flow rate of fixtures by letting them run for a minute and then measure the water to estimate the fixture flow rate. Manual estimates are more accurate in estimating your needs.

4. Fuel type
Now that you have decided on the tankless water heater’s brand and capacity, you need to decide on the fuel. Typically, a gas-fueled tankless water heater is cheaper to operate, as the general prices of natural gas are less than the electricity. However, it is not always true. Therefore, you need to find out which fuel is the cheaper power source, as it will affect your savings.
You also need to compare the prices of these units and their fuel to find which is more beneficial for you. Suppose there is not much difference between gas and electricity prices. In that case, an electricity-powered tankless unit is more beneficial for you. As electric tankless units are, their unit cost is much cheaper than gas-fueled tankless units.
5. Energy Factor:
Energy factors are another essential feature that you need to see in a tankless water heater. An energy factor tells you about the energy efficiency of a unit. Most of the traditional tank water heaters’ energy factor ranges from 0.5-0.6. What it means is that if a tank unit consumes $1 of fuel, then it is only using 50-60 cents of fuel to heat the water while the rest become lost.
The most gas-fueled tankless water heater comes with an energy factor of 0.8. At the same time, its condensing variant can give you a 0.9 energy factor. In contrast, an electric tankless water heater comes with an energy factor of 0.98. Nevertheless, even though electric tankless have higher energy and energy efficiency, they are more expensive to operate, as electricity is more expensive than gas.
The important thing to note regarding the energy factor is that some utility companies give rebates. Suppose the purchased unit has a higher than particular energy factor. In that case, you could be eligible to receive rebates on your unit.
6. Indoor or outdoor
Tankless comes in both indoor and outdoor versions. Both have their pros and cons. For example, suppose you live in icy areas with a certain chance of water freezing inside the tankless unit. In that case, it is wiser to install an indoor unit. In warmer regions, outdoor units are a wiser choice now; you do not need to install the ventilation.
An outdoor tankless unit can take a longer time to bring water to the fixture due to the larger distance. While installing an outdoor unit makes it on the safer side in case you feel worried about having a unit powered by combusting gases inside your house.
An outdoor tankless unit also comes as a convenience as some people do not like plumbers roaming around the house. Therefore, the plumber does not need to enter your house with the outdoor tankless water heater unit. Similarly, the dirt or garbage cleaned by the plumber does not lie around your house to clean it up.
Frequently Asked Questions
How many BTU do I need for a tankless water heater?
A tankless water heater requires 190,000 BTU with a maximum value of 199,000 BTU. It is 4-5 times more than what a traditional tank water heater requires of 40,000 BTU.
Can a tankless water heater be too big?
Tankless water heaters come in different sizes because people have different needs levels. Understanding your need and buying a suitable size to match is an intelligent choice. If you purchase a bigger size, you are paying for something that you will not need or use. On the other hand, purchasing a smaller size can leave you hanging when you need it the most.
What size tankless water heater do I need for a family of 7?
For a family of seven, you will need a gas tankless unit that gives a capacity of 11GPM or a 34+ KW electric tankless unit. However, such estimates are not accurate as there are many factors you need to consider. Some of them are as follows.
1. The temperature of water in your region. A tankless water heater will take a longer time to heat water that is icy cold. In this case, although you may have a higher capacity unit, you will get a lower capacity of hot water as tankless takes time to heat the water.
2. Your everyday hot water needs
3. Your peak-hour hot water needs
Conclusion
Choosing a tankless water heater is quite similar to shortlisting the best one from several alternatives. By following the above sequence, you can quickly identify a tankless water heater suitable for your need and be your partner in a lifelong journey.
I appreciate you talking about the energy factor when considering tankless water heaters. Energy matters a lot to us here at home, especially since we end up using those appliances a lot more than other families. I’ll work on finding a water heater service in the area that can offer us an energy-efficient tankless model.