Well to get an accurate answer you d have to calculate out how much hot water you typically use during your busiest hot water using hour.
Water heater size for family of 3.
If your space won t accommodate a standard size water heater there are alternatives.
But if you only need a loose estimate of what size you need versus an exact calculation follow these guidelines.
40 gallons family of 3 4.
To determine temperature rise subtract the incoming water temperature from the desired output temperature.
How to determine the size of a water heater tank.
The bigger the water heater tank the more expensive it will be.
This is because water heater size directly impacts its cost.
What size water heater do i need.
To reduce flow rates install low flow water fixtures.
That s the measure of how much hot water the heater will deliver during a busy hour such as first thing in the morning.
40 gallons family of 5 or more.
Family of 1 2.
The first factor in choosing a tankless water heater is calculating the size of your hot water heater.
While traditional tank water heaters are calculated by your family size a tankless water heater is calculated by the quantity and types of fixtures or appliances it will serve.
2 3 people you ll need at least a 40 gallon capacity tank.
If you re going with a storage tank water heater here s a rough guide for storage tank capacity.
For 2 to 3 people.
1 2 people you ll need a water tank with at least a 30 gallon capacity.
2 3 people need a 40 gallon water heater 3 4 people need a 40 50 gallon water heater 5 or more people need a 50 80 gallon water heater now before you make your final decision there is one other consideration to make and it s a big one.
For a tank style heater household size is a simple indicator of hot water needs.
Once you have your total flow rate and the required temperature rise you can find the right size tankless water heater for your home.
30 gallons family of 2 3.
For 1 to 2 people.
You can estimate the necessary tank capacity in gallons based on the number of people in the house.
Below we ve highlighted what size water heater you would need in our example of 6 5 gpm at a 63 f temperature rise.
How to size a tankless water heater.
The flow rate through the demand water heater would need to be at least 3 25 gallons 12 3 liters per minute.
The good news is that just by following a few guidelines you can find the perfect size water heater.
Determine the home s fhr or first hour rating.