To determine the appropriate size of a tankless water heater for your household, you need to consider two main factors: the flow rate (GPM) and the temperature rise (ΔT)
. The general guidelines for sizing tankless water heaters are as follows:
- 3.5 GPM for 1-2 fixtures simultaneously
- 5 GPM for 2-3 fixtures simultaneously
- 7 GPM for 3-4 fixtures simultaneously
However, these numbers can vary depending on your household's specific needs and factors such as the size of your home, the number of appliances running at once, and the climate in your area
. To find the right size tankless water heater for your home, you can use a tankless water heater sizing calculator, like Navien's NaviSizer, which takes into account your tankless water heater application and provides the correct size recommendation
. Keep in mind that choosing a tankless water heater that is too small may result in insufficient hot water, while a too-large heater will be more costly than necessary
. It is recommended to work with a professional plumber to determine the best size tankless water heater for your home
