How Many Tankless Water Heaters Do You Need To Meet Your Home's Hot Water Demand?

3 November 2021
 Categories: , Blog


Tankless water heaters provide a continuous supply of hot water. Unlike tank systems, they do not store water in a large tank. Therefore, they are incredibly energy-efficient and convenient to use. However, before buying a tankless water heater, it's crucial to assess your demand. Some homes may require more than one tankless unit while others can get away with a single unit. Below are a few factors to consider when choosing the right number of tankless hot water units to install in your home.

How Water Consumption Patterns

Tankless water heaters have a limited flow rate of around four to eight gallons per minute (GPM). Therefore, even though a tankless unit doesn't typically run out of hot water, it can fail to meet the demand if it has a low flow rate. For example, a 5GPM water heater can only heat five gallons of water every minute. Thus, if you run multiple hot water fixtures simultaneously and exceed the unit's flow rate, you won't get adequate hot water. 

Therefore, large households that use a lot of hot water can invest in one large tankless unit or two smaller ones. If one system doesn't provide the desired flow rate, you can install two water heaters to serve different fixtures. This way, you don't have to worry about running out of hot water. Conversely, if you have a small household with low demand for hot water, you can opt for one tankless unit.

Distance to the Furthest Outlets

Tankless water heaters don't usually provide hot water instantly. When you turn on a shower or hot water faucet, the unit's heat exchanger takes a few seconds to start up and heat the water. Once heated, the water takes a few more seconds to reach the outlet point. The further away the outlet point is, the longer it will take for hot water to be available. 

If you have a large home, the fixtures that are far away from the tankless unit may take longer to receive hot water. If your pipes aren't insulated, the heated water may lose heat due to the surroundings before reaching the access points. Thus, it's advisable to install another tankless unit to serve further water outlets. 

Availability of Point-of-Use Systems

Point-of-use systems are small tankless water heaters that are used to serve individual fixtures. You can use these systems to heat water for your faucets. Homes with a high demand for hot water can invest in a primary tankless unit and one or two point-of-use systems for specific uses. For example, installing a small tankless water heater in the kitchen will reduce the load on your primary hot water system and ensure a continuous supply of hot water.

Contact a local plumber for further consultation and water heater installation services.