Tankless Hot Water Heater Guide

Simply put, a tankless hot water heater is a demand water heater or instantaneous water heater that provides hot water only when needed.

It doesn't require the storage (and associated standby energy loss/cost) of a conventional storage tank system. And, since it produces hot water on demand, you never need to wait for your tank to fill up and you never run out of hot water.

 

 

How Does A Tankless Hot Water Heater Work?

In a conventional storage tank system, when you turn on a hot water tap, the hot water that is stored in the tank is released through your pipes and delivered to you.

In a tankless system, when you turn on your hot water tap, the system becomes activated and cold water enters the unit. It is immediately heated by an electric element or a gas burner before leaving the unit and working its way through your pipes in the same way as a conventional storage tank system.

 

 

The main difference is that instead of storing and continually heating water in a tank and depleting that supply, the tankless system only works ON DEMAND and delivers a constant supply of hot water as long as it is operating within its capacity. You never need to wait for your hot water tank to fill up so you never run out of hot water, and the system only uses energy as needed.

How Much Hot Water ?

Hot water output and flow rate depends on which system you buy and what type of energy it uses. There are point-of-use systems, which are small units that service individual appliances or a single point application (e.g. bathroom) and whole house systems.

A smaller tankless hot water heater won't be able to supply enough hot water for larger households with multiple points of demand occurring at the same time. In other words, running the washing machine and taking a bath at the same time may be too much for a smaller system. However, there are some larger whole house tankless water heaters (especially gas fired ones) that have better flow rates and can accommodate higher demand.

Another thing to keep in mind with tankless water heaters, is that you can install more than one and have them connected in parallel or have one or more dedicated to specific appliances or areas of your home. Since they don't consume energy unless they're being used, multiple installations can service even the largest mansions. And, as mentioned in the video above, smaller systems are really ideal for house additions—eliminating all sorts of extra costs associated with additional plumbing and increasing capacity of your existing system.

How To Choose A Tankless Hot Water Heater

The first things you need to take into consideration when choosing a tankless water heater are the following:

Application: Are you looking at a point-of-use or whole house system? An addition to your existing system? Replacement for your existing conventional tank system?

Demand: What are the demands on the system? How many showers, baths major appliances does the system need to service?

Geographic Location: Where are you located and what is your ambient incoming water temperature? If you live down south like in Florida or Georgia, your incoming water temperature will be significantly higher than if you live in New England or up north. This is important, along with 'Demand', to determine how powerful and what size your tankless water heater needs to be.

Gas or Electric: What fuel types can you consider? Are there any particular constraints, in your situation, for installing a tankless water heater such as access to natural gas, insufficient electrical power or local building code requirements.

Stay tuned for more on selecting a demand water heater and how to compare one tankless hot water heater system to another. We'll look at the pros and cons of select models and discuss individual tankless water heater manufacturers and potential tax credits.

Finally, take a look at our page on tankless water heater cost and learn what you need to consider when comparing price tags.