Today:24 May, 2024

Boiler versus water heater: comparison of hot water heating systems

Maintaining a small or large home is not an easy task, especially if you need to run some systems, like a boiler and water heater. It is an essential home system, especially during colder months. A homeowner either chooses a boiler or water heater. If you want to change your water heating system to either of the two, it is good to know the difference between the water heating systems.

Here is essential information that you should know before you decide which one to purchase.

What is a water heater?

A water heater produces heat, of course, through a burning gas or electricity. Hence, it will keep the water at a high temperature until it is used. Afterward, the hot water will be replaced by cold water coming from the bottom of the tank.

Types of water heaters

There are two common types of water heaters, which are conventional and tankless. However, there are other types for you to choose from:

  • Conventional storage tank water heater

tank water heater

It is the oldest type of water heater that uses a large tank. The cold and freshwater enter goes through the bottom of the tank and heated at the desired temperature.

  • Tankless (on-demand) water heater

Electric tankless water heaters

The on-demand water heater is one of the most efficient types as it can heat the water instantly. Also, it is best for houses with small space.

  • Heat pump water heater

Heat pump water heater

Among other types, it is energy efficient as it uses heat coming from the air or ground. However, it is not a wise choice for cold spaces.

  • Solar-powered water heater

Solar-powered water heater

If you live in a sunny and warmer region, it is the best type for you. Solar thermal panels take energy from the sun, and a system will convert it into electricity.

  • Condensing water heater

Condensing water heater

It uses the conventional storage tank with a condenser to make it more efficient.

Oil vs electric water heater

The cost of heating water today is getting higher each year. That is why it is essential to know which operating system can offer both efficiency and affordability. However, it is good to ask for expert advice before deciding which type of water heater is best for your home.

  • Oil water heaters

The oil type provides faster reheating time compared to electric models. Although it is limited depending on the fuel source, it is highly recommended. It can heat the water three to four times faster than fuel and has a longer lifespan. The negative side is its high maintenance cost.

  • Electric water heaters

It is a tank type that is easier to buy, install, and least expensive. Aside from that, the electric type is cleaner, low maintenance than the gas type. The reason is that it has no sediment build-up. The drawback is that it has a high operating cost compared to gas or oil type.

What is a boiler?

Water heating boiler turns water into steam. a boiler is not only useful for water heating, but it can heat your home. You can choose a gas boiler, water heater, or electric boiler. There are also tank and tankless versions.

How does a boiler work?

It is the center of the heating system around the house. The boiler tank sends heated water to the radiators and taps to supply heating and hot water. How does it all work?

  1. Once the home thermostat senses a drop in temperature inside the house, the boiler will automatically turn on.
  2. It uses oil, gas, or electricity to make heat.
  3. The water inside the boiler will heat up.
  4. Using radiators, the heated water will heat your home and water.
  5. The cold water will travel back to the boiler for reheating and send it back to the radiator to continue the process.

Types of boilers

After knowing how a boiler works, let’s find out the different types of water heating boilers.

  • Hot water boiler

This system uses temperature, volume, and pressure to give reliable and safe heating systems. However, the negative side of it is different from a water heater because it uses a separate tank to heat tap water for radiators.

  • Natural gas boiler

It uses a gas line that runs underneath the house via a pipeline. Most hot water boiler system from natural gas uses propane. However, the only problem is that most rural area does not have a mainline for natural gas.

Moreover, one can easily regulate temperature using a gauge and a thermocouple for lesser fuel usage. The heating coils are kept warm by the natural gas and pass the heat to the tank’s water.

  • Oil boiler

It is also known as an oil-fired boiler, which is very common in rural areas with no natural gas access. The water is heated using a combination of biodiesel and heating oil. An old boiler system is inefficient and not environment friendly. It is because of the continuous pilot light. If you want a new version, you may choose to replace the entire unit.

  • Electric boiler

Despite many different types of boilers for home available, it remains the most on-demand water heating system. There are no fumes left, easy to clean, and no need for main gas or fuel supply. Therefore, it is best for homeowners living in rural areas.

However, it is not all sweet. There are disadvantages too. The cost of electricity is getting higher and higher every year. It is also prone to power outages, and there is no huge boiler tank for larger properties.

  • Condensing boiler

There are two separate exchangers for this type of boiler: to heat the water before going to the radiator and reheat water before going back to the house’s piping. It is more energy-efficient as it uses exhaust gas to reheat the returning water going to the boiler.

  • Steam boiler

It uses gravity and pressure to deliver hot steam to the radiators and go back cooled condensation to the boiler for reheating. However, it needs octant checking to ensure that the gauge ensures an appropriate level. Also, it requires maintenance to keep it in good shape. In case of a knocking noise inside, it means that it is already malfunctioning.

  • Combi boiler

When you do not need space heating during summer, you may only use it for water heating. On the other hand, it heats the entire home in colder months and provides domestic hot water.

What to look for when choosing between a boiler and a water heater

There are similarities and differences between boiler and water heater. It is good to find out your needs first. There are essential factors to consider, such as:

  • The climate in your area
  • Space available in your property
  • Number of people who will use the water supply
  • On-demand access to hot water

Installation cost

Boiler installation cost

Boiler installation costs range from $3,000 to $11,000. So, for example, a standard model with an efficiency of up to 90% AFUE will cost up to $6,000. Higher efficiency models can cost twice as much. These costs include labor ($1,000- $3,000). The installation cost depends a lot on the brand, the type of boiler, and the need for BTU.

Installation of a water heater is usually several times cheaper than installing a boiler. So, for an ordinary water heater, you will pay up to $2,000, for a tankless water heater up to $3,000.


How to use a boiler

For steam heating, the boiler heats the water using gar or oil and turns the water into hot steam. Afterward, the steam will go to the pipes and travel to the radiators that give off heat to the entire house. Once the steam cools down, it will turn into water and back to the boiler for heating.

How to use a water heater

The water will go to the main water line to the house. But before the water heater, there is a split line that makes up the house water intake system. By turning on hot tap water, the water will pass through the shut-off valve, travel in the dip tube, and go into the water heater tank. The water is heated at the bottom of the tank. Lastly, the hottest water will rise at the top of the tank.


Any heating system requires maintenance tasks. It is to ensure that the system will always run smoothly.

How to maintain the boiler there is some maintenance procedure to extend the lifespan of the boiler.

  • The vent and the chimney are very prone to deterioration. So, it is vital to scrutinize it and look for possible leaks.
  • Always examine the heat exchanger as it mostly causes the leak.
  • It is also good to flush out the boiler to get rid of rust debris and other build-ups. This step is essential to avoid a clog.
  • Take time to lubricate the circulating pump to ensure a smooth flow of water.

For water heating maintenance, there are easy steps for you to keep in mind.

  • Do not forget to drain at least a quarter of the tank to remove sediments inside the tank.
  • Also, it is good to test the temperature and pressure relief valve yearly. You can do it by discharging twice pr thrice.
  • Check the anode rod every two to three years by removing the hex head screw.
  • In case you need to leave for few days, it is good to set the thermostat into “vacation mode.”

The lifespan

Every manufacturer set a lifespan for boiler and water heater, but the common life expectancy is 8 to 12 years. It may vary according to your design, location, installation quality, and maintenance schedule. Additionally, the water quality in your area is a huge factor in its lifespan.

Radiant floor heating: water heater vs boiler

One of the most common homeowners’ questions is, “How big of a water heater do I need for radiant heat?” However, before you think of the size, it is important to find out the type that suits your needs.

Water heater for radiant floor

It is a good option for a radiant floor because it is efficient and has a low temperature. However, it is essential to consider the incoming water and how cold it is. The colder the groundwater, the longer it takes o warm the floor.

Boiler for radiant heat

Many think that the boiler does a great job for radiant floor heating. However, the drawback is that it uses two systems for heating and hot domestic water. The best boiler is the one that does not quickly drop in temperature.

Hopefully, after reading this article, it helps you gain enough knowledge about the heating system. Therefore it can help make a wise decision as to what type best suits your needs and budget.

Joseph is the founder and Chief Editor of "Indoor To Outdoor". He is an entrepreneur with experience in sales of household products. He also travels a lot, takes pictures and loves to ride a bike.

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