How Tankless Water Heaters Work

Are you considering installing a new water heater, but are unsure if you want to invest in a tankless or tank water heater? Before you make a decision, learn how tankless water heaters work and why they are up to 35% more cost efficient than traditional tank water heaters.

How Do Tankless Water Heaters Work?

Tankless water heaters, also called on-demand water heaters or instant water heaters, heat water on when hot water is needed. Because they do not heat an entire tank of water (and keep it heated day and night, regardless of the demand for or lack of demand for hot water), tankless water heaters don’t cost you in the energy costs associated with keeping a tank of water hot at all times.

Here’s how tankless water heaters work on demand:

Tankless water heaters heat water directly as you need it. When a hot water tap is turned on, cold water travels through a pipe into the tankless water heater unit. Either a gas burner or an electric element heats the water as it passes through, delivering instant hot water. Energy costs are lower because the tankless unit only heats water when you need it, as you need it.

Our favorite brand of tankless water heater is the Rinnai tankless water heater. Watch this short video to see how the tankless water heater works.

How Do Tank Water Heaters Work?

Most homes have a tank water heater as this is the most common way to heat water for your home. Tank water heater units heat water 24/7, even when hot water is not needed. This is because tank water heaters have to compensate for standby heat loss. While the water storage tank is insulated, this insulation only slows heat loss, and every time hot water is used, cold water is piped into the tank, cooling the heated water already in the tank slightly. To maintain hot water in the tank, the water heater burner cycles on and off throughout the day and night. This ensures the availability of hot water.

The average tank water heaters has a usable capacity of approximately 70%, which means a 50-gallon tank has about 30-35 gallons of hot water heated and ready for usage. When those usable gallons of hot water have been used up, you will have to wait for the tank to heat the water up again since the new water coming into the tank will be cold, cooling some of the hot water as the available hot water is used up.

Need Help Deciding Between Tank or Tankless?

Check out our pros and cons lists here. Then give us a call at 704.846.5371. We take the time to talk through options and make sure you choose the right water heater for your home. Let’s talk soon!