Tankless water heaters provide an endless supply of hot water on-demand, making them a popular alternative to hot water tanks. But how does a tankless water heater work? If you have one or you’re interested in purchasing one, it’s need-to-know information.
Why You Need to Know How a Tankless Water Heater Works
If your home has a tankless water heater, understanding how it works is an important piece of homeowner information. Even if you don’t have one, it’s still useful to know, especially if there’s a chance you might install one the next time your hot water tank needs replacing.
- If your tankless water heater breaks down, you’ll have a better idea of whether it’s a minor issue you can fix yourself or if you need to call a plumbing technician.
- Having some background knowledge about tankless heaters can help you communicate with plumbing technicians about repairs and maintenance.
- When you need to replace your current water heating system, that knowledge may help you decide what to purchase.
What Exactly Is a Tankless Water Heater?
Everyone’s familiar with tank-style water-heating systems. The water is held in a heated tank and depleted whenever you use hot water. Fresh water is heated over time. If you use a lot of hot water, you can potentially run out.
Tankless heaters are the exact opposite. Instead of heating water over time, water is heated more-or-less instantly. That means there’s no need for a tank and no risk of running out of hot water. Even on heavy-use days, a large family can still use as much hot water as they want and not run out.
The only limitation with a tankless heater is flow rate, which is usually measured in gallons per minute. For standard tankless heaters, maximum flow rate is up to five gallons per minute. The best-of-the-best can reach over 13 gallons of water per minute.
Maximum flow rate varies depending on the model and capacity of the system, and whether it’s gas-powered or electric. Maximum flow also depends on the degree to which you want to heat the water. The hotter you want the water to be, the lower the maximum flow rate will be.
Maximum flow rate determines how many different appliances and faucets can use hot water at the same time. The higher the rate, the more faucets and appliances can run simultaneously. Where this is an issue, adding a second tankless water heater can solve the problem.
How Does a Tankless Water Heater Work?
Once the unit is installed, set up, and switched on, it works effectively to give you an unending supply of hot water when you need it. Once your tankless water heater has been installed, it’s not usually necessary to turn it on or off or change the temperature settings, unless you have a particular reason to do so. For instance, if you’ve moved into a new home and it has a tankless system, you may want to adjust the flow rate or temperature to your liking.
Tankless water heaters have a master power switch and a control panel, both of which are typically on the unit itself. The control panel lets you change the temperature to which the water is heated. This in turn allows you to adjust the flow rate of your hot water. Increasing the temperature reduces the flow rate, and vice versa.
The control panel also controls the operation of the system when it heats water. It ensures each part of the process happens in the right order.
So how does a tankless hot water system work?
When you turn on a hot water faucet or hot-water-using appliance, the system kicks into gear. Cold water flows into the tankless heater unit. A flow sensor inside the tankless unit detects the flow and triggers the unit to start heating.
As the cold water flows through the unit, it comes into contact with the heat exchanger. This is either an electric heating coil or a gas burner. This part of the unit is typically structured as an S-shaped pipe, with the heating elements inside. The water flows through the pipe, and heat is transferred to the water.
By the time the water has passed through the heating element, it’s heated to the set temperature. It flows through the pipes until it reaches the faucet or appliance that was turned on.
Are Electric and Gas-Powered Tankless Water Heaters Different?
Electric-powered systems are a little less complicated than gas tankless water heaters. In an electric system, when the flow sensor is triggered, it activates the electric heating elements. Copper coils connected to the heating elements also heat up. The water passes over the copper coils, and heat transfers from the coils to the water.
The system also has two thermostats. One measures the temperature of cold water entering the heating chamber, and one measures the temperature of the hot water as it exits the tankless unit. These two thermostats work together to ensure water is heated to the set temperature.
The process is more complicated in a gas-powered system because there are some extra safety components needed to control gas flow. It starts the same way: When you turn on a hot faucet, cold water flows into the unit, and this is detected by the flow sensor.
The flow sensor triggers two separate processes:
- The gas flow
- The gas igniter
The igniter emits sparks that ignite the gas. If the igniter fails to work after a few seconds, the control panel shuts off the gas flow. This is done to prevent an unsafe build-up of gas.
Once the gas is burning, the combustion process heats up the heat exchanger. As the cold water passes through, heat transfers to the water until it exits the system at the correct temperature.
Gas-powered tankless water heaters require a venting system to safely remove combustion gases from inside the home. This isn’t needed with an electric tankless system.
Thinking About a Tankless Water Heater For Your Home? Call CW Service Pros for Help
If you’re currently using a tanked water heater, switching to a tankless system can be a more cost-effective option. Plus, it saves space in the home and, most importantly, gives you an unending supply of hot water! Call CW Service Pros for expert advice on your options or to talk about installing a tankless water heating system for your home.