HowMuchIt / Video
What size water heater do I need? The 7-second version
Seven seconds: the shower runs cold, so count your busiest hour. Then size your own heater with the calculator.
Open the calculator: What size water heater do I need?
What the video shows
Someone steps out of a shower that has just turned cold, then we see a tank water heater and a small tankless unit side by side. Running out of hot water is almost always a question of the busiest hour, not of the size printed on the tank.
Do it for your home
For a tank, count what happens in your busiest hour: showers, dishwasher loads, washer loads, shaves, hand dishes. The calculator adds the gallons and gives the first hour rating to look for on the yellow EnergyGuide label. For a tankless heater, count the showers and faucets running at the same time, and type the hot water you want and the cold water coming in: the calculator gives the flow and the temperature rise.
Before you replace yours
- Running out in the morning points to the peak hour.
- Measure your cold tap in winter if you can.
- Gas, venting and electrical work call for a licensed plumber or electrician.
On screen, word for word
- What size water heater do I need?
- Count your busiest hour.