Can you run tankless water heaters in series?

Also to know is, can you put two tankless water heaters together?

If the flow rate falls below a threshold both units will stop and the water will run cold. Rinnai has the lowest minimum flow but there is still no reason to double it. If you are planning to connect two tankless water heaters to each other, it is best to do it in series.

Beside above, what is the downside of a tankless water heater? Tankless water heaters produce an endless supply of hot water, take up less space, have a lower risk of leaking, are safer, and have a significantly longer lifespan on average. The main disadvantage of tankless water heaters is their upfront cost (unit and installation) is significantly higher than tank-style heaters.

Hereof, do I need one or two tankless water heaters?

For larger households that typically use more than 85 gallons per day, two tankless systems, or the largest available model, are likely needed. For smaller households that use under 40 gallons per day, one unit should suffice. They are miniature tankless water heaters designed for use at one outlet, such as a sink.

How many tankless water heaters do I need?

Average Temp. For example, if you are running 2 showers at the same time, you will need 5 gallons of hot water per minute from the tankless water heater. If you were running a shower and the washing machine at the same time, you would need 4.5 gallons per minute from the water heater.