An instant water heater, or tankless water heater, is an alternative to the hot water tank that’s a mainstay in most homes. While hot water tanks are still the more common option, tankless water heaters have some big benefits and are an increasingly popular alternative.
You might also hear them called:
- Continuous flow water heater
- Flash water heater
- Demand-type water heater
- On-demand water heater
- Inline water heater
What Is an Instant Water Heater?
An instant water heater heats water on demand rather than keeping a tank of water hot, like a traditional tank water heater. This also means you never run out of hot water.
While tankless water heaters are often called “instant water heaters,” it’s important to note that hot water isn’t technically “instant.” The only way to truly get hot water instantly is to also install a recirculating system. When you install a recirculating pump, it creates a loop that constantly circulates the water in the hot water pipes back into the water heater to be reheated. When you open a faucet, hot water is already in the pipes, so you don’t waste water down the drain as you wait for it to heat up.
How an Instant Water Heater Works
A tankless water heater is a heating unit that connects to your home’s cold water supply line. Inside the instant heater unit, several components work to heat the water as it passes through the unit. There’s a thermostat and a control panel that lets you adjust the temperature and flow rate of the hot water. There’s also a master power switch to turn the whole system on and off.
Here’s how it all works:
- When you turn on a hot water faucet, cold water starts to flow into the instant heating unit.
- As cold water flows into the heating unit, a sensor detects the flow and triggers the heat exchanger.
- The heat exchanger is an electric heating coil or gas burner. It’s structured as an S-shaped pipe, and the heating elements are contained within the pipe.
- Cold water flows through the heat exchanger pipe and heats up as it passes over the heating element.
- By the time the water exits the heating unit, it’s heated to the temperature set on the thermostat.
- The water exits via a water outlet and from there flows via the home plumbing system to wherever it’s needed in your home.
Instant gas and electric water heaters work similarly, but gas tankless water heaters have some extra components to control the flow of gas into the heating unit. There’s also a ventilation system to vent harmful combustion gases safely outside.
Instant Water Heater Pros and Cons
Pro: Endless Hot Water
The best-known benefit of the tankless heater is that it provides a never-ending supply of hot water. Because water is heated instantly on demand, it’s always available, even on a heavy-use day. No matter how much hot water you use, more is always available.
Con: But With a Limited Flow Rate
The flip side of “unlimited hot water” is that you are limited by flow rate, which refers to how many gallons of hot water the tankless system can produce every minute. In a tankless system, the flow rate is determined by the model you own and the temperature setting of your tankless water heater. The higher your water temperature, the lower the flow rate, and vice versa.
This can cause issues in a large household because a low flow rate limits how much hot water you can use at once. This might mean, for instance, that two separate showers can’t run at the same time or that you can’t run the dishwasher while the shower is in use. A related issue is that if the demand for hot water exceeds the flow rate, this can trigger the water heater to shut off. With some models, this can mean a wait of several hours before the heater starts to operate normally again.
Buying a higher-end model can help with this issue. You can also install multiple heating units to increase your total flow rate.
Con: Slow Flow Can Trigger a Shutdown
On-demand water heaters are sensitive to issues that reduce the flow rate of your hot water. If the flow rate is significantly reduced, it can trigger the heating unit to shut off. This can happen if a faucet or showerhead gets clogged or even if there’s a lot of limescale buildup in your plumbing.
Pro: Lower Operating Costs
With storage tank water heaters, water is heated and then maintained at that temperature until it’s needed. This can mean energy is wasted keeping the water hot, even when it’s not needed. Instant water heaters are more energy efficient than hot water tanks because water is only heated when you need it. Tankless water heater systems are up to 34% more energy efficient than storage tank systems. This makes them an environmentally friendly choice, thanks to a lower carbon footprint.
Con: Higher Purchase Cost
While continuous flow water heaters cost less to run, they cost more to purchase. That means your up-front costs are higher compared to the cost of a tank water heater. It can also cost more to install a tankless water heater because it might be necessary to upgrade your water pipes or add a new gas line or vent stack. The total cost depends on your plumbing needs, so it’s hard to estimate until you know what those needs are.
Note: Depending on the kind of instant water heater you buy, you may qualify for a rebate. To quality, look for models that are certified by the Energy Star program.
Pro: Longer Lifespan
Instant heaters may require a larger financial investment up front, but a gas tankless heater can last twice as long as a gas hot water tank. This can tip the balance even further in favor of the tankless system when it comes to annual running costs.
Pro: Space Saving
If storage space is at a premium in your home, switching to an instant hot water system provides another benefit. It takes up much less space than a hot water storage tank, so there’s the potential to free up some valuable storage room along with the other benefits.
Pro: Wi-Fi Compatible
The newest tankless water heaters have Wi-Fi connectivity. They can connect to an app that lets you manage your hot water temperature via your phone. You can monitor your hot water usage, adjust the thermostat, and even troubleshoot problems with your system.
Types of Instant Water Heaters and How to Choose One
There are several different types of tankless water heaters. Before you decide, consider:
- Size – Think about how big your family is and how many hot water fixtures you run at the same time.
- Fuel type – The options are tankless electric or tankless gas.
It’s also a great idea to speak with a licensed plumber before making a commitment. A CW Service Pro can help you understand your options and the factors that go into making a great decision.
Electric
While not as efficient as a gas water heater, a tankless electric heater generally costs less to install. It doesn’t require a ventilation system, which means it can be installed almost anywhere, even in small spaces. However, it may not be able to supply the hot water demand of the home.
Gas
Natural gas or propane-powered instant water heaters heat water more quickly than electric tankless water heaters. Gas and propane are less expensive than electric power, but these water heaters have a higher cost to install, and they generally need more maintenance. They need to be flushed out annually to clean the scale build-up off of the heat exchanger to keep it from burning up.
Call CW Service Pros to Power Up Your Home Hot Water System with an Instant Water Heater
Are you tired of your hot water tank and the money you’re spending to store hot water? An instant water heater for your home could be your hot water solution. Call CW Service Pros to learn about your options. Your home could benefit from saving space, saving water, and reducing utility costs. Plus, you’ll enjoy an unlimited supply of hot water all day, every day. Call CW Service Pros for expert advice, water heater installation, and more.