What Size Tankless Water Heater Do I Need?

Getting the right size water heater can get confusing, especially if you need to know the answers to these questions. 

The size of a tankless water heater is only sometimes well-explained. Some are just listed by their energy factor, which is a very minimal definition. It gives you little detail about what to expect from the water heater.

If you need to properly prepare for how much hot water, you need in your home, you might have to upgrade again down the road.

What Size Tankless Water Heater Do I Need?

A tankless water heater should be enough to supply a mid-sized family. If you have over five people in your household, it’s time to upgrade to a larger model.

Tankless water heaters come in different sizes and capacities. The most popular sizes are 30, 50, 75, and 100 gallons per minute (GPM). Here are some examples of the different units:

30 GPM – This is a good choice if you have less than three people living in your home. It can provide hot water for showers or dishwashing by hand since it provides enough hot water for laundry. In minutes, you can also fill an outdoor pool or Jacuzzi tub with warm water!

50 GPM – This size works well for smaller homes with 4-5 occupants where everyone needs hot water at once.

How to Select the Right Size Tankless Water Heater

When it comes to selecting the right size tankless water heater for your home, there are several factors that you must consider.

Here are some things to think about when selecting a unit:

Space limitations–The first thing you need to consider is whether you have enough space for a tankless water heater. Many tankless models require a specific location to function properly. If you don’t have the right location, then you shouldn’t buy the unit.

Water usage–You must also consider how much water is used in your home on an average day. The more people live in your home, the more water they will use daily. 

This will help determine how much of a tankless unit you need for your home and how much energy it will save over time compared to traditional storage units.

Water availability–A third thing that must be considered is whether there is enough water available for your tankless model to work correctly having no issues with low pressure or flow rate issues because of a lack of supply pressure from your local utility company or municipality’s infrastructure system.

How Often Should I Flush My Tankless Water Heater?

If you have a family of five or more that showers and bathes daily, then flushing your water heater every year will be necessary. 

How often you flush your tankless water heater depends on your use. The more frequently you use your tankless water heater, the more often it needs to be flushed. 

However, if only one person uses the hot water in their shower and bathroom sink daily, flushing every two years suffices to keep your system clean and functioning properly.

It’s important to remember that flushing your water heater will help keep it in good working order. It will also ensure that you have hot water at all times and prevent the possibility of leaks or other issues.

It’s not uncommon for homeowners to wonder how often they should flush their tankless water heaters. While it depends on the type of water heater, some general guidelines apply to most models.

How to Clean my Tankless Water Heater

You should clean your tankless water heater regularly. Here’s how:

  • Turn off the power to your tankless water heater, and make sure you have an unoccupied space to work in that is away from any ignition source (such as gas or electric appliances).
  • Open up the cover of your tankless water heater by removing screws or latches, and check for any visible buildup of dirt or dust on its surfaces. Use a vacuum cleaner with a soft brush attachment to clean them off completely before continuing with this step below.
  • Pour some vinegar into a bucket full of cold tap water, then dip a sponge into it so that it’s thoroughly wetted down before using it on inconspicuous parts inside your unit like pipes and nozzles where mold might lurk unnoticed by sight alone; this will help prevent any staining from occurring during use later on when cleaning time comes around again.

Why Do You Need To Flush A Tankless Water Heater?

The most common reason is to prevent corrosion and mineral build-up. This can cause the unit to malfunction or break down before its time. 

The flushing process removes these minerals through running water and prevents them from accumulating in the system.

Another reason is that the heaters develop sediment over time, which can also lead to build-up within the pipes. 

This will reduce the flow of water through your system, which can cause problems with heating efficiency and reduce hot water output. Flushing also helps prevent this sediment from causing damage in the long run by removing it before it builds up too much.

Finally, flushing your tankless water heater regularly helps keep it clean and free from bacteria buildup that could otherwise cause serious health issues when consumed by family members or pets who regularly drink from your tap water supply.


The first step in deciding what size tankless water heater you need is to plan. Think about your future needs and decide where and how you want the unit installed, and then purchase a water heater that will best meet those demands.

In most situations, a larger tankless water heater will give you more bang for your buck, but if you’re on a tight budget, it might be worth considering a smaller model that would cover the bare minimum needs.

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