Tankless Water Heaters: The Comprehensive Guide to Efficient Water Heating

Are you tired of running out of hot water in the middle of a shower or waiting for the water to heat up?

If so, it might be time to buy and upgrade to a tankless water heater. With their energy-efficient design, space-saving size, and endless supply of hot water, tankless heaters have become an increasingly popular option for homeowners.

In this comprehensive guide, we’ll explore the pros and cons of tankless water heaters, compare them to traditional tanks, provide tips on sizing and installation, and share our top picks and reviews to help you find the best type and model for your home.

What Is a Tankless Water Heater?

A tankless water heater is an efficient, space-saving solution for providing hot water in residential and commercial settings.

Unlike its traditional counterpart-tank type that stores heated water in a large tank, the tankless variant does not hold water internally for heating purposes.

Instead, it heats water on demand, offering a continuous supply of hot water without the need for a bulky storage tank.

This sleek and compact design allows for greater flexibility in installation locations, including small spaces or walls, making it an ideal choice for those looking to maximize their use of space.

Tankless are known for the high energy efficiency and the convenience of providing hot water exactly when it’s needed, catering to the modern lifestyle’s demands for efficiency and sustainability.

Types of Tankless Water Heaters

Tankless water heaters come in a variety of types, each catering to different needs and energy sources. The primary types include electric and gas-fired models.

Electric models use electrical resistance elements to heat water on demand. They are known for their compact size and efficiency, making them suitable for smaller homes or point-of-use applications, such as under sinks. Electric models require significant electrical power, which may necessitate an electrical system upgrade.

Gas-fired models utilize natural gas or propane to heat the water. They are more powerful than electric models and can handle a higher demand for hot water, making them ideal for larger households. Gas-powered units require venting to the outside to expel exhaust gases, which can add to the installation complexity.

Condensing tankless water heaters use a dual heat exchange system to maximize efficiency. They capture heat from the exhaust gases in addition to the heat generated directly for water heating. This process allows them to achieve higher efficiency ratings by utilizing almost all the heat generated, with some models reaching efficiencies of up to 98%.

Non-condensing types are the more traditional type, where the exhaust gases are vented outside without being used for additional heating. They typically have efficiency ratings around 80-85%, making them less efficient than their condensing counterparts but still more efficient than traditional tank heaters.

Non-condensing units are often less expensive and simpler to install, making them a viable option for many households.

How Does a Tankless Water Heater Work?

A tankless water heater, whether electric or gas-powered type, heats water on demand, eliminating the need for a bulky storage tank.

When you open a hot water tap, cold water flows through a pipe into the unit. The water is then heated instantly by either an electric element or a gas burner, depending on the heater type.

How Electric Models Work?

Electric tankless water heaters provide an efficient, on-demand hot water solution by heating water directly with electric elements as it flows through the unit.

A flow sensor activates these heaters when you turn on the hot water tap. They quickly heat incoming cold water to a preset temperature, providing an endless supply without needing a bulky storage tank.

The system’s innovative modulation capability allows it to adjust energy output to match water flow, optimizing efficiency and minimizing waste.

Additionally, many models feature user-friendly control panels for temperature adjustments, equipped with digital displays for monitoring and, in some cases, remote controls for convenience, making the management of hot water supply both efficient and adaptable to user needs.

How Gas Models Work?

Modern gas-powered tankless water heaters, exemplified by brands like Rinnai, Noritz, Takagi, and Paloma, incorporate more features and components than their electric counterparts. One advanced feature is the use of sophisticated technology to precisely manage temperature, flow, and safety through electronic control boards.

These systems initiate heating when a flow sensor detects water movement, triggering a gas valve that allows fuel-either natural gas or propane-to ignite in a combustion chamber, heating water instantaneously via a heat exchanger to a preset temperature for an uninterrupted hot water supply.

Key to their efficiency, these heaters include features such as modulating gas valves, which adjust the fuel flow to match demand, enhancing energy conservation and ensuring consistent water temperature, even during peak usage.

Advanced models also boast condensing technology, capturing heat from exhaust gases for even greater efficiency, while adhering to safety regulations through necessary venting to expel gases outside. This integration of technology and design ensures a responsive, energy-efficient hot water system with reduced environmental impact.

Video: Tankless Basics

Pros And Cons of Tankless Water Heaters

Tankless water heaters offer a modern approach to supplying hot water that comes with its own set of advantages and drawbacks. Understanding these can help homeowners make informed decisions based on their specific needs and circumstances.

Advantages and Benefits

• Endless hot water supply: Unlike traditional heaters, tankless water heaters provide a continuous supply of hot water, ensuring that you never run out.
• Durability: They are built to last, with a lifespan of 20 years or more for some models.
• Energy and cost savings: By heating water on demand, tankless heaters can save you up to 50% on energy and heating costs compared to traditional heaters. Additionally, high-efficiency models are available as Energy Star, ensuring that you save money and energy.
• Lower greenhouse gas emissions: Tankless produce lower greenhouse gas emissions compared to traditional heaters, making them a more environmentally friendly option.
• Less leaking problems: Since there is no tank, the risk of leaking is reduced.
• Smart technology: Some models use smart technology with self-diagnostic programs and error codes for troubleshooting and repairs, as well as precise temperature control for enhanced safety and comfort.

Disadvantages

• Tankless systems can have high upfront costs, up to three times more than tank-type heaters.
• Upgrades like venting or gas lines can be expensive.
• Inconsistent water temperature or “cold-water sandwich” is one of the frequent problems that can occur with economy-type units.
• Venting gas and propane units require costly stainless steel tubing, and some brands may use other materials.
• Electric instant water heaters may require an additional circuit and use a lot of energy.
• Gas models require annual servicing, which adds additional expenses.
• Instant heaters require a minimum flow rate to activate the heat exchanger.
• Tankless water heaters rely on the pressure delivered to the home, making a good plumbing system necessary.

What to Consider When Buying a Tankless Water Heater?

When considering the purchase of a tankless water heater, several key factors should be evaluated:

Fuel type: Determine if an electric, natural gas or propane tankless type is most suitable for your home. Also consider whether it can be integrated with solar panels for enhanced energy efficiency. The best option depends on fuel availability, cost, and necessary home modifications.

Size and flow rate: Evaluate the size of the unit in terms of its ability to handle your household’s hot water demand. Tankless water heaters indicate their performance based on the maximum temperature rise achievable at a specific flow rate. To choose the right unit, determine how much hot water you use during peak times. Consider peak usage and multiple fixtures running simultaneously.

Energy efficiency: Look for units with high energy efficiency ratings to maximize your energy and cost savings over time. Energy-efficient models may qualify for rebates or tax credits, which can offset the higher initial cost.

Installation and ventilation requirements: Understand the installation requirements, including necessary venting for gas models. Also, check if your current electrical system supports electric models. Installation significantly impacts the total cost, especially if your home’s infrastructure requires upgrades.

Costs: Consider both the upfront cost of purchasing the unit and the long-term operating costs. While tankless water heaters are more expensive initially, they can offer lower operating costs by using less energy. Calculate the potential energy savings to determine if the investment makes sense for your budget.

Brand and warranty: Research different brands and read reviews to assess reliability and customer satisfaction. Additionally, compare warranty periods and what they cover. A longer, more comprehensive warranty can provide peace of mind and protect your investment.

Local regulations and rebates: Check local building codes and regulations regarding tankless installation. Some areas may have specific requirements or offer rebates for installing energy-efficient models.

Sizing a Tankless Water Heater

When considering a tankless water heater for your home, selecting the right size is crucial to ensure it meets your hot water demands efficiently.

You calculate peak hot water demand by adding the flow rates of fixtures used simultaneously. Determine the required temperature rise by comparing incoming water temperature to your desired temperature.

Proper sizing affects not only the heater’s ability to deliver hot water but also its energy efficiency and longevity.

For a comprehensive guide on how to accurately to size your unit, including detailed calculations for flow rates and temperature rise, visit: sizing tankless water heaters.

How Much Does a Tankless Water Heater Cost?

The cost of a tankless water heater varies widely based on the type (gas or electric), brand, capacity, and efficiency.

Electric models range from $500 to $1,500, while gas-powered units can cost between $1,000 and $2,000, excluding installation fees.

Installation costs vary between $500 and $2,000, depending on complexity, required upgrades to lines, and venting for gas models.

For example, a high-efficiency gas model like the Rinnai RU199iN offers a 11 GPM flow rate suitable for larger homes and can cost around $1,800 for the unit alone.

An electric model, like the Stiebel Eltron Tempra 24 Plus, features self-modulating technology and energy efficiency, costing around $700.

It’s important to consider both the upfront purchase and installation costs along with the long-term savings.

Compare Tankless vs. Tank

When comparing tankless water heaters to traditional tank models, consider the benefits of energy efficiency and unlimited hot water. However, weigh these benefits against initial costs and installation requirements.

Tankless models, though more expensive upfront, offer long-term savings on energy bills due to their on-demand heating capability. There is no standby energy loss as found on tank heaters.

On the other hand, tank type has a lower initial purchase and installation cost. However, they may lead to higher operating expenses due to their continuous heating process.

The decision also hinges on household water usage, space considerations, and the existing infrastructure of your home.

Tankless Water Heater Brands

When exploring the market for tankless water heaters, certain brands stand out for efficiency, reliability, and variety in electric and gas models.

EcoSmart and Stiebel Eltron lead the pack in the electric category, offering innovative and energy-saving features tailored to various household sizes.

Rheem and Bosch also excel with their compact, efficient electric models designed for longevity and performance.

For gas-powered options Rinnai, Takagi, and Navien stand out for their advanced technology and user-friendly features. Noritz is known for its eco-friendly, high-efficiency models.

These brands are celebrated not only for their product quality but also for exceptional features, quality, and warranties.

How to Install a Tankless Water Heater

Installing a tankless water heater, whether electric or gas, is a complex process that requires careful planning and precision.

Start by evaluating your home’s power and water infrastructure for compatibility. Then, choose an appropriate installation location that follows building codes. Lastly, make any necessary adjustments to electrical panels or gas lines.

Follow the manufacturer’s instructions for mounting the unit, connecting it to the water supply. For gas models ensure proper venting to safely expel exhaust gases.

Hiring a professional installer is highly recommended due to the technical expertise required, especially for gas lines or electrical upgrades.

Tankless Water Heater Maintenance

Maintaining a tankless water heater ensures efficiency, longevity, and safe operation, including winterizing to prevent damage in colder climates.

Regular maintenance tasks include descaling the heat exchanger, cleaning the air and water filters, and inspecting gas venting systems.

Periodically check for signs of wear, leaks, and test water pressure to prevent strain on the heater. Basic maintenance, like cleaning filters, can be done by homeowners, but professional service is recommended for tasks like descaling.

Professional maintenance is recommended at least once a year to address any potential issues and keep the system running smoothly.

How Long Do Tankless Water Heaters Last?

Tankless water heaters boast an impressive lifespan, typically exceeding 20 years, significantly outlasting traditional tank-based models. Their durable design reduces wear from continuous heating and storage of water.

To ensure optimal performance and longevity, follow a regular maintenance schedule, including descaling to remove mineral deposits.

These units often come with substantial warranties, sometimes up to 15 years, offering added peace of mind for your investment.

Although the initial cost is higher, the extended lifespan and energy efficiency of tankless water heaters provide long-term savings, making them cost-effective.

Are Tankless Water Heaters Worth It?

In conclusion, tankless water heaters offer energy efficiency, long lifespan, and a continuous supply of hot water, making them a great alternative to traditional tank heaters.

Homeowners seeking to lower energy bills, reduce environmental impact, and enjoy reliable hot water should consider a tankless type.

Although they may require a higher initial investment, the long-term savings and benefits make it a worthwhile investment for homeowners.

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