The Basics About Water Heaters:Types, Parts and How They Work

Water heaters are the unsung heroes of modern household comfort, silently toiling away to ensure that your showers are warm, your dishes are clean, and a multitude of daily tasks are executed with the right temperature. Despite their crucial role, they often go unnoticed until something goes wrong.

In this comprehensive guide, we explore the world of water heaters in detail, helping homeowners understand the various types available, the intricate parts that keep them running, and crucial insights into their functioning. 

If you’ve ever pondered the differences between a tankless system and a traditional storage tank water heater, or you’ve been daunted by the prospect of replacing your home’s heating system, this post is for you. We’ve got you covered from the moment hot water is demanded to the agile response of these essential home appliances.

Types of Water Heaters

There are primarily three types of water heaters that you can consider for your home. Each comes with its set of advantages and disadvantages, depending on your specific requirements.

Tankless Water HeatersHow They Work

Tankless water heaters, also known as on-demand water heaters, heat water directly without the use of a storage tank. A flow sensor activates the heating mechanism when you turn on the hot water tap, and the water passes through a series of high-powered burners or electric coils, heating it to the required temperature almost instantly.

Pros and Cons


  • Energy efficiency – no standby heat loss since there’s no tank to constantly heat the water
  • Unlimited hot water – as long as there’s proper sizing and adequate water and gas or electric supply
  • Space-saving – tankless systems are smaller and can be mounted on walls


  • Higher upfront costs – tankless water heaters can cost more to purchase and install
  • Output limits – limited by the flow rate of the water heater, so simultaneous use can be a problem
  • Retrofitting complexity – installing a tankless system in a home designed for traditional water heaters might need significant alterations to gas lines or venting.

Conventional Storage Tank Water HeatersHow They Work

These are the most common type of water heaters, using a large tank to store and heat water. Cold water enters the bottom of the tank and is heated by either a gas burner or electric heating elements. A thermostat monitors the temperature and activates the heating elements as needed.

Pros and Cons


  • Lower initial cost
  • Simplicity – easy to install and maintain
  • Immediate availability – as hot water is stored, it’s available as soon as a faucet is turned on


  • Standby heat loss – the energy is used to keep the water hot, even when the water heater isn’t in use
  • Limited hot water supply – the size of the tank determines the amount of hot water available at one time
  • Shorter lifespan – they typically last 10-15 years, whereas tankless heaters can last over 20 years.

Heat Pump Water HeatersHow They Work

These innovative water heaters move heat rather than generating it directly. They pull warmth from the air and use it to heat the water in the tank. They work like a refrigerator but in reverse—where a fridge extracts heat from its interior to keep things cool, a heat pump water heater uses the ambient air to keep the water inside its tank warm.

Pros and Cons


  • Energy efficiency – heat pump water heaters consume less energy, saving you money on your utility bills.
  • Environmentally friendly – they produce fewer greenhouse gas emissions compared to electric or gas tanks.
  • Lower humidity – they can also dehumidify the space where they are installed.


  • Higher installation cost – heat pump water heaters come with a higher price tag.
  • Cooling effects – in warm climates, the cooling function can become a downplayed bonus, as it cools down the surrounding air while heating the water.
  • Location dependency – the availability of warm ambient air is critical for the effective operation of a heat pump water heater.

Parts of a Water Heater

Water heaters consist of several essential parts that work together to provide you with consistent hot water supply.

Common Components across all TypesHeating Elements/Tank

The heart of the water heater is the heating mechanism, whether it’s gas burners, electric coils, or a heat pump. It applies the necessary heat to raise the cold water’s temperature to the pre-set level.

Pressure Relief Valve

This crucial safety feature will release water or steam if the pressure inside the tank gets too high, preventing the tank from exploding.


The thermostat controls the water temperature inside the tank and also turns the heating elements on and off as required to maintain the set temperature.

Unique Parts in Different Types

Each water heater type comes with specific components that cater to its unique method of heating water. For instance, a tankless system might have high-efficiency heat exchangers, while a heat pump water heater integrates a fan, evaporator, compressor, and refrigerant to function effectively.

How Water Heaters Work

Understanding how a water heater functions is key to maintaining an efficient system.

Basic Mechanics of Heating Water

  • Tank storage: The tank fills with cold water that is then heated and stored until needed.
  • Tankless systems: Water passes through the heating apparatus without being stored, ensuring a continuous supply.
  • Heat pumps: These systems capture warmth from the air and transfer it to the water to raise its temperature.

Energy Efficiency Considerations

When choosing a water heater, it’s crucial to consider the long-term energy costs. Tankless systems are lauded for their efficiency, but the initial cost can be significantly higher. Heat pump water heaters are also highly efficient but might not be practical in all climates.

Maintenance Tips to Keep Them Working Efficiently

Regular maintenance is essential for the optimal operation of your water heater.

  • Flush the tank: Sediment can build up and affect the unit’s efficiency over time, so a periodic tank flush is recommended.
  • Check the anode rod: This rod attracts corrosive elements in the water and can become a key maintenance point over time.
  • Inspect for leaks and rust: Keeping an eye on the integrity of the tank can prevent costly water damage.

Choosing the Right Water Heater for Your Home

Selecting the right water heater involves several considerations to ensure it meets your household’s needs and aligns with your values.

Factors to ConsiderHousehold Size and Demand

The number of people in your home and their hot water usage habits will dictate the size and type of water heater you need. Larger families or homes with high water demands may benefit more from a high-capacity storage tank system.

Energy Efficiency

Your geographical location and energy costs play a significant role. Determine which type of system will provide the best balance of performance and cost-savings in the long run.

Space Availability

Not all homes can easily accommodate a water heater. Tankless and heat pump systems are especially advantageous for smaller homes with space restrictions.

Comparing the Types Based on the Above Factors

A thorough comparison of the different types of water heaters considering your specific household variables should narrow down your ideal choice. Tankless systems might be perfect for energy-conscious individuals living in smaller household units, while traditional storage tank systems are a reliable choice for those seeking affordability and straightforward functionality.

Water heaters are indispensable appliances that offer comfort and convenience to modern life. Understanding the types available, the parts that make them tick, and how to choose the right one for your home is empowering and can save you time, money, and headaches down the line.

Remember, when it comes to water heaters, informed decision-making is the keystone of a comfortable home. Make sure to assess your household’s hot water demands, consider the long-term energy costs, and contemplate installation and maintenance implications carefully.

If you’re still uncertain or need professional advice, don’t hesitate to reach out to a trusted plumber or home service provider. With this knowledge in hand, you’re ready to tackle the world of water heaters and ensure that your home’s hot water supply remains steady for years to come. If you are in need of a water heater repair or a replacement, contact your local Hamilton Plumbers today at Rescue Rooter! 

Leave a Reply

Your email address will not be published. Required fields are marked *