How Do Tankless Water Heaters Work (Guide)
If you’re tired of running out of hot water or noticing skyrocketing energy bills from your traditional water heater, switching to a tankless water heater (also known as an on-demand water heater) could be a game-changer for your home. But how does a tankless water heater work, and why might it be a better choice for your household?
At Aquarius Home Services, we’re here to ensure you feel confident when upgrading your home systems. This blog will break down:
- How tankless water heaters operate
- Their benefits
- Tips for deciding if a tankless system is the right fit for your home
What Is a Tankless Water Heater?

A tankless water heater is a modern heating system that eliminates the need for a bulky water storage tank. Unlike traditional water heaters, which store and heat a large volume of water at once, tankless systems heat water only as needed. This means you won’t be storing gallons of pre-heated water but rather heating water on-demand, ensuring a continuous supply of hot water whenever you need it.
How Does a Tankless Water Heater Work?
A tankless water heater operates using a compact heating unit, installed on a wall or near your water lines. Here’s a step-by-step look at how a tankless water heater functions:
Hot Water Demand is Triggered
When you turn on a hot water faucet, shower, or appliance (like a washing machine), cold water flows into the tankless water heater.
Sensors Detect Flow
Sensors within the unit detect the flow of water and immediately activate the system. This triggers the heating mechanism, which can use either gas burners or electric heating elements to warm the incoming water.
Instant Heating Begins
Once the system activates, water flows through a heat exchanger inside the unit. The heat exchanger rapidly heats the water to your desired temperature. This process happens in seconds, meaning hot water is delivered almost instantly to your faucet or shower.
Hot Water Delivered to Your Home
The heated water is then sent through your plumbing system, arriving right at the location where it’s needed—a showerhead, kitchen sink, or washing machine. Since the water is heated on-demand, you won’t have to worry about running out of hot water.
System Shuts Down When Water Stops Flowing
When you turn off the faucet or appliance, the sensors detect that the water flow has stopped, and the heating process shuts down. This efficient design ensures energy is used only when hot water is required, reducing unnecessary power consumption compared to traditional systems.
6 Key Benefits of a Tankless Water Heater

Now that you understand how a tankless water heater works, you’re probably wondering why so many homeowners are making the switch. Below are the key benefits of this innovative system:
1. Endless Hot Water Supply
One of the standout benefits of a tankless water heater is its ability to provide continuous hot water. Whether you’re tackling a marathon laundry day, running the dishwasher, or enjoying a long shower, you’ll have hot water whenever you need it—no interruptions.
2. Energy Efficiency
Traditional water heaters store hot water in a tank, using energy to keep the water warm even when it’s not being used. This “standby heat loss” leads to wasted energy and higher utility bills. Tankless water heaters heat water only on-demand, meaning they use significantly less energy overall. According to the U.S. Department of Energy, tankless water heaters are 24%-34% more efficient for homes that use less than 41 gallons of hot water daily.
3. Space-Saving Design
Say goodbye to the bulky tank that takes up valuable space in your basement or utility room. Tankless water heaters are compact and can be installed on a wall, freeing up room in your home. This sleek design is particularly appealing to homeowners who value a minimalist and organized home environment.
4. Longer Lifespan
On average, tankless water heaters last up to 20 years, compared to the typical lifespan of 8-12 years for traditional water heaters. While the upfront cost may be higher, the long-term savings and durability make tankless systems a wise investment.
5. Lower Utility Bills
By operating more efficiently and only heating water as needed, tankless water heaters can help you save on your energy bills. Over time, these savings can add up, making the switch not only an environmentally friendly choice but also a financially smart one.
6. Cleaner, Fresher Water
Water stored in traditional tanks can accumulate sediment and rust over time, which may affect the taste and quality of your water. Tankless systems eliminate this issue since they don’t store water, ensuring every drop is as fresh as possible.
Electric vs. Gas Tankless Water Heaters
There are two main types of tankless water heaters to choose from—electric and gas-powered. Deciding which option is right for your home depends on factors like your household’s hot water demand and your home’s existing infrastructure.
Electric Tankless Water Heaters
- Ideal for smaller households with lower hot water needs
- More energy-efficient overall, especially in homes with renewable energy sources
- Easier and less expensive to install than gas models
- Best for mild climates where incoming water doesn’t need as much heating
Gas-Powered Tankless Water Heaters
- Can meet high hot water demands, making them a great option for larger households
- Heat water faster than electric models
- Require a venting system due to exhaust gases, which can increase installation complexity and cost
- Excellent choice for homes that already use natural gas or propane
Our Aquarius Home Services team is happy to help assess your needs and recommend the ideal model for your home.
Is a Tankless Water Heater Right for Your Home?

While tankless water heaters offer many benefits, they’re not the perfect solution for everyone. Here are some factors to consider:
✅ Pros of Tankless Systems:
- Need consistent hot water—large families will benefit from endless hot water supplies.
- Want to save on monthly energy bills.
- Have limited space available for installation.
- Plan to stay in your home long enough to recoup the investment in energy savings.
❌ Drawbacks to Be Aware Of:
- Higher upfront cost compared to traditional storage tanks.
- Installation may require significant retrofitting, especially if switching from a traditional system.
- May struggle to supply simultaneous hot water needs for multiple fixtures in larger homes if the unit isn’t sized properly.
If you’re unsure if a tankless water heater is the right upgrade for your home, reach out to our team today. We’ll evaluate your household needs, energy goals, and budget to provide personalized recommendations.
Professional Installation and Maintenance
A tankless water heater is a high-tech system that requires professional installation to guarantee optimal performance. At Aquarius Home Services, our expert technicians ensure everything is installed safely and correctly, from proper positioning to venting for gas-powered models.
Once installed, maintenance is relatively simple but essential for keeping your tankless system running at peak performance:
- Flush the unit annually to remove any mineral buildup, especially in areas with hard water.
- Clean or replace filters regularly to prevent clogs or blockages.
- Schedule routine inspections with a professional to catch and address any potential issues early.
The Aquarius Home Services team offers comprehensive maintenance plans to keep your system in tip-top shape year-round.
Make the Switch with Aquarius Home Services
Upgrading to a tankless water heater is an investment in comfort, efficiency, and sustainability for your home. With endless hot water on demand, lower energy bills, and minimal space requirements, it’s no wonder so many homeowners are making the switch.
If you’re ready to enhance your home’s water heating system, trust Aquarius Home Services to guide you through every step of the process—from selecting the right model to expert installation and maintenance. Our team is here to answer any questions, provide advice tailored to your household, and ensure you’re thrilled with your new tankless water heater.Contact us today to schedule a consultation and start saving energy while enjoying the endless hot water you deserve!