Are you tired of running out of hot water in the shower or waiting for your water heater tank to slowly heat up? If so, you may be considering switching to a tankless water heater. These on-demand water heaters provide an endless supply of hot water by only heating water as you need it.
But how do tankless water heaters work to provide such a convenient supply of hot H2O?
If you’re short on time, here’s a quick answer to your question: Tankless water heaters heat water directly without the use of a storage tank. Cold water passes through a heat exchanger that rapidly heats the water only as needed. This on-demand design provides a continuous flow of hot water.
In this detailed guide, we’ll explain the inner workings of tankless water heaters. You’ll learn how the major components like the heat exchanger, gas burner, and flow sensor allow tankless heaters to heat water instantly and efficiently.
We’ll also compare tankless vs tank water heaters so you can decide which is best for your home.
What is a Tankless Water Heater?
A tankless water heater, also known as an on-demand water heater or instant water heater, is a modern appliance that provides hot water without the need for a storage tank. Unlike traditional water heaters, which store a large amount of hot water in a tank and constantly heat it, tankless water heaters heat water directly as it passes through the unit.
This allows for a continuous supply of hot water, eliminating the need to wait for a tank to refill and reheat.
Basic Design and Operation
Tankless water heaters are compact in size and can be installed in various locations, such as under sinks or in utility rooms. They are typically powered by electricity, natural gas, or propane. When a hot water tap is opened, cold water enters the unit and passes through a heat exchanger.
The heat exchanger quickly heats the water to the desired temperature, and then the hot water flows out of the faucet or showerhead. The heating process is controlled by a flow sensor and a thermostat, ensuring that the water temperature remains consistent.
Benefits of Tankless Water Heaters
There are several advantages to using a tankless water heater. Firstly, they provide hot water on demand, so there is no need to wait for a tank to refill and reheat. This is especially beneficial for households with multiple bathrooms or high hot water demand.
Additionally, tankless water heaters are more energy-efficient than traditional water heaters because they only heat water when it is needed. This can result in significant energy savings and lower utility bills.
Furthermore, tankless water heaters have a longer lifespan compared to traditional models, with an average lifespan of 20 years or more.
According to the U.S. Department of Energy, tankless water heaters can be 24-34% more energy-efficient than traditional storage tank water heaters for households that use 41 gallons or less of hot water daily.
For households that use a lot of hot water, around 86 gallons per day, tankless water heaters can still be 8-14% more energy-efficient. This makes them a greener and more eco-friendly option for homeowners.
Drawbacks of Tankless Water Heaters
While tankless water heaters offer numerous benefits, there are also some drawbacks to consider. Firstly, the upfront cost of a tankless water heater is generally higher than that of a traditional water heater. However, the long-term energy savings can offset this initial investment.
Additionally, tankless water heaters may have a lower flow rate compared to traditional models, which means they may not be suitable for homes with high-demand hot water usage. It is important to consider the specific needs of your household when deciding whether a tankless water heater is the right choice.
Furthermore, it is recommended to have a professional install a tankless water heater to ensure it is properly vented and connected to the appropriate power source. Regular maintenance is also necessary to prevent scaling and mineral buildup, which can affect the performance and efficiency of the unit.
Overall, despite these drawbacks, tankless water heaters offer a convenient and energy-efficient solution for providing hot water in homes and businesses.
How Does a Tankless Water Heater Heat Water?
A tankless water heater, also known as an on-demand water heater, operates differently from traditional water heaters. Instead of storing and heating a large amount of water in a tank, a tankless water heater heats water as it passes through the unit.
This process eliminates the need for a storage tank, resulting in energy savings and a continuous supply of hot water.
Heat Exchanger
The heart of a tankless water heater is the heat exchanger. This component is responsible for heating the water as it flows through the unit. The heat exchanger is typically made of high-quality materials such as copper or stainless steel, which have excellent heat conductivity.
As water passes through the heat exchanger, it absorbs the heat generated by the unit, raising its temperature to the desired level.
Gas Burner or Electric Heating Elements
Tankless water heaters can be powered by either a gas burner or electric heating elements. Gas-powered units use a gas burner to heat the water. The burner ignites when the hot water tap is turned on, and the flames heat the heat exchanger.
Electric tankless water heaters, on the other hand, use electric heating elements to heat the water. These heating elements are activated when the hot water is needed, and they quickly heat the water as it passes through the unit.
Flow Sensor
A flow sensor is another crucial component of a tankless water heater. This sensor detects when hot water is being requested and signals the heating system to start operating. When the flow sensor detects water flowing through the unit, it activates the gas burner or electric heating elements, ensuring that hot water is available on demand.
This feature helps conserve energy since the unit only heats water when it is needed, rather than constantly maintaining a tank of hot water.
Microprocessor
Modern tankless water heaters often include a microprocessor that controls and regulates the unit’s operations. The microprocessor monitors various factors such as water flow rate, temperature, and safety features.
It ensures that the water is heated to the desired temperature and prevents overheating or other malfunctions. Additionally, some tankless water heaters can be programmed or adjusted using a control panel or smartphone app, allowing users to customize their hot water settings to their preferences.
Tankless vs Tank Water Heaters
When it comes to choosing a water heater for your home, you may come across two main options: tankless water heaters and traditional tank water heaters. Both types have their own advantages and disadvantages, and it’s important to understand how they differ before making a decision.
Hot Water Output
One of the main differences between tankless and tank water heaters is the hot water output. Tank water heaters store and heat a specific amount of water, usually ranging from 30 to 80 gallons. This means that once the hot water in the tank is used, you may need to wait for the tank to refill and heat up again before you can have access to hot water.
On the other hand, tankless water heaters heat water on demand. They don’t store hot water, but rather heat it as it flows through the unit. This means that you have a continuous supply of hot water, as long as the unit can keep up with the demand.
So, if you have a large household with multiple people needing hot water simultaneously, a tankless water heater may be a better option for you.
Energy Efficiency
When it comes to energy efficiency, tankless water heaters have the upper hand. Because they only heat water as it is needed, they don’t waste energy keeping a large tank of water constantly hot. This can result in significant energy savings over time.
According to the U.S. Department of Energy, tankless water heaters can be up to 34% more energy efficient than traditional tank water heaters. This means that not only will you save money on your energy bills, but you’ll also reduce your carbon footprint.
Upfront Costs
While tankless water heaters may offer long-term energy savings, they do have higher upfront costs compared to tank water heaters. The installation of a tankless water heater can be more complex, as it requires additional plumbing and electrical work.
Additionally, the unit itself tends to be more expensive than a tank water heater.
However, it’s important to consider the long-term savings that a tankless water heater can provide. Over time, the energy savings can offset the higher initial investment.
Maintenance
Maintenance is another aspect to consider when choosing between a tankless and tank water heater. Tankless water heaters generally require less maintenance than tank water heaters. They don’t have a tank that can accumulate sediment or rust, which can negatively affect the performance and lifespan of a tank water heater.
However, it’s still recommended to schedule regular maintenance for your tankless water heater to ensure optimal performance. This may include flushing the unit to remove any mineral build-up and checking for any potential issues.
Installing a Tankless Water Heater
When it comes to installing a tankless water heater, there are a few important factors to consider. Proper sizing for demand, ventilation requirements, gas line size, and electrical service upgrade are all key elements that need to be taken into account.
Sizing for Demand
One of the first steps in installing a tankless water heater is determining the appropriate size for your household’s hot water needs. Unlike traditional water heaters, tankless units heat water on-demand, meaning they don’t store hot water in a tank.
Instead, they heat the water as it flows through the unit. To ensure you have enough hot water for your household, it’s crucial to consider factors such as the number of bathrooms, appliances, and occupants that will be using hot water simultaneously.
It’s recommended to consult a professional plumber or use online sizing calculators to determine the right size for your specific needs.
Ventilation Requirements
Proper ventilation is essential for the safe operation of a tankless water heater. These units produce exhaust gases that need to be vented outdoors. The type of venting system required will depend on the specific model and fuel type of the tankless water heater.
Some units may require direct venting, while others may use a power vent or a condensing vent system. It’s important to consult the manufacturer’s instructions or hire a professional to ensure that the ventilation is installed correctly and meets all safety requirements.
Gas Line Size
If you are installing a gas-powered tankless water heater, you will need to ensure that the gas line size is appropriate for the unit’s requirements. Gas tankless water heaters typically require a larger gas line than traditional water heaters due to their higher heating capacity.
It’s crucial to consult a professional plumber or a gas supplier to determine the correct gas line size and ensure that it meets local building codes.
Electrical Service Upgrade
Electric tankless water heaters may require an electrical service upgrade to accommodate their power needs. These units typically require higher voltage and amperage than traditional water heaters. It’s essential to consult an electrician to assess your electrical system’s capacity and determine if any upgrades are necessary to safely operate the tankless water heater.
Upgrading the electrical service may involve installing a new circuit breaker, wiring, or even a larger electrical panel.
Conclusion
Tankless water heaters provide hot water on demand by rapidly heating water as it flows through the system. Key components like the heat exchanger, burner, and flow sensor allow tankless heaters to heat water instantly without the need for a storage tank.
While tankless heaters have a higher upfront cost, they can save money over time through greater energy efficiency and longevity.
If endless hot water sounds appealing, a tankless heater may be right for your home. Just be sure to properly size the tankless heater for your household’s peak demand and factor in any electrical or ventilation upgrades needed during installation.
With some smart planning, you can enjoy the convenience and efficiency of a tankless water heater.
