A Complete Guide: 5 Types Of Water Heaters And How They Work

Looking to purchase a water heater but have zero knowledge of the different types available? Buying an unsuitable heater type can cost you more in the long run. All water heaters are built to emit hot water, and this is possible through a complex working of different parts and components. Technicalities aside, you just need to find the right one for your specific needs, be it a condominium or sprawling good class bungalow.

In this guide, you’ll encounter five different types of water heaters, namely gas, electric, digital, heat pump, and solar. Each has its benefits, advantages, and recommended maintenance techniques. Go through each of them and weigh out your options. This will help you make the ultimate decision for the most ideal device that fits your requirements.


Gas Water Heater

Before choosing a gas water heater, it is important to note the inspection, installation, and maintenance. This is because there are risks associated with having a gas system, such as flammability, chemical composition of air, and proximity to combustible structures (to name a few). You’ll find this type of heater often installed outdoors, primarily for safety reasons and to reduce potential property damage.

How A Gas Water Heater Works

As long as the gas supply is compatible and all precautions are taken during installation and servicing, a gas water heater should be able to provide you with a comfortable amount of hot water for a shower. The system works through a gas-fired burner that heats the cold water stream as it passes through. Once the burner has been lit, it remains powered on until the cold water stream is shut off

Gas water heaters come with safety mechanisms, particularly to protect against gas leaks. Get your gas heater checked often to prevent accidents caused by overheating, leaks, or even bursts.

Pros And Cons Of Gas Water Heaters

Gas water heaters can provide instantaneous heating, which is perfect for families that require hot water on demand.

However, there are downsides to this type of heater. Installation and service can be slow, given the limited number of licensed companies operating in Singapore. Additionally, costs can be higher for places that haven’t been previously installed with a gas water heater. Compared to electric water heaters, hot water consistency and water pressure are low.


Electric Water Heater (Generation 1)

A large part of your home’s electric bill is dedicated to powering heating devices. One of these is the electric water heater, which has become a staple in many establishments. Most households and hotels opt for electric water heaters over gas heaters. This comes as no surprise because electric water heaters have lower upfront costs, are safe and reliable, and have comparatively good water pressure output

How An Electric Water Heater (Gen 1) Works

Think of an electric heater as an insulated kettle. Water in the tank is heated quickly with high-powered heating elements. The hot water is then stored within a well-insulated tank, available for on-demand use for the family. With few moving parts, electric heaters can repeat this cycle for well over 10 years with little or no downtime.

How To Maintain An Electric Water Heater (Gen 1)

To prolong the life of an electric heater, take care to inspect its safety components from time to time. This includes the element, wiring, relief valve and thermostat. To keep the tank water clean, perform a tank flushing once every few years. Be on the lookout for any signs of corrosion or leaks. This signals that the heater needs to be changed soon.


Digital Water Heater (Generation 6 to 8)

Digital water heaters are the high-technology version of the regular generation 1 electric water heaters. They supercharge your hot water output so it more than doubles. At the same time, they factor in the busy lifestyle of a typical Singaporean family by integrating the instant function. The instant function is a speed heating technology that allows users to get hot water in 2 minutes compared to 20 minutes, as with heaters in the past. If you have a growing family or just love your hot showers, the digital water heater may be a perfect fit for you.

How A Digital Water Heater Works

Unlike older water heater units, digital water heaters can provide hot water in a matter of minutes. The unit also functions by heating water with high-powered electric heating elements. However, this heating process differs from generation-1 electric heaters because the internal tanks of digital heaters are specially structured to maximise heating efficiency. Internal sensors are also strategically placed to initiate optimal water flow to more than double effective hot water output. Now your family of four can take back-to-back showers without worrying about running out of hot water midway.

How Much Can You Save With A Digital Water Heater?

Compared to the typical tank heater, you will save both time and money. Speed heating ensures you can get hot water 80% faster than a regular electric heater. On top of that, digital water heaters are more energy-efficient. Use an in-built intuitive control panel to set a timer or adjust your ideal running mode. The right settings can save you 10% of energy costs.


Heat Pump Water Heater

As renewable energy water heater systems, heat pumps and solar heaters will offer you energy savings that will far outperform gas, electric or even digital water heaters.

How A Pump Water Heater Works

Where the previous models operate by a heat-creation mechanism, heat pump water heaters simply absorb free air heat from the ambient air. Heat pumps work in pretty much the same manner as an air conditioning unit or a refrigerator, except in reverse. Air-conditioners remove heat from a room and transfer it to the compressor while heat pumps remove heat from the air and transfer it into the heater.

Where To Install A Heat Pump Water Heater

One great benefit of living in the tropics means you have free flexibility for heat pump installation locations. Without winters to contend with, heat pumps run at high efficiency at all times of the year. The minimum ambient temperature requirement? An easily attainable 15ºC. Place your heat pump at the service yard of your condominium or HDB. Bigger floor standing heat pump units can go on the ground floor or flat roof of a landed property. Some have found that efficiency increases placing a heat pump close to their aircon compressor units.


Solar Water Heater

The drive for sustainable investments continues to grow in Singapore, and this is no less in the water heater market. Families or businesses in need of water heating systems but want to become more sustainable and reduce carbon footprint can also benefit from solar heaters.

How A Solar Water Heater System Works

In a solar water heater system, the solar collector is one of the most critical components. Through a continuously-flowing energy source provided by the sun, heat is transferred through the collectors and then towards a water storage tank. All of this is made possible through solar heater collectors (not to be confused with PV cells, which run on a different operating principle) that collect solar energy to heat the water.

When Is The Best Time To Use A Solar Water Heater

Solar energy is readily available but a solar water heater is at its peak when used during the day or under cloudless skies. Solar heater tanks are sized much larger than average water heaters because collecting solar energy is a slow process that takes several hours. The large tank size compensates for the slow heating time by providing sufficient hot water volume to fulfil the household demands. This is a great hot water solution without all the carbon dioxide emissions. Do note that due to its large tank size, solar heaters are usually only installed in landed homes. Their operating efficiency is estimated at 50%.



There is no one-size-fits-all water heater that can be used for all households. Each family’s requirements are different, and every housing type comes with its unique requirements. It is possible for you to do your research and find a system that solves your water heating problems and delivers considerable savings.

In this guide, we’ve explored the five most popular types of water heaters in Singapore and how each of them works. If you are still unsure of the best choice, reach out to us. As water heating specialists at AOS Bath, we have got you covered. We can give you advice on all the various heaters on this list and give you care tips to ensure your unit lasts for decades. To start off, simply take 2 minutes to complete this quiz, and we would love to work through the options available to you.


Frequently Asked Questions About The Types Of Water Heaters

Instant heaters produce unlimited hot water with 50% lower water pressure. Storage heaters have limited hot water with high water pressure.

Several factors can affect the heating time of your unit. It could be the distance from the water source, the presence of a low volume restrictor, or an overused water heater. Ensure your unit is well-maintained and that it’s properly installed. If none of this works, you can call AOS Bath professionals to help you rule out any issues.

Although water heaters generally use up significant electricity, you can choose a renewable energy type heater to save energy and money. Insulating the unit, lowering the temperature, and making sure the faucet is fully closed when not in use are some practices you can do to save on utility bills.

There may be faulty or damaged heating components in your unit that are causing it to fail. If you’re having second thoughts about inspecting it yourself, contact us at AOS Bath, and we can help replace parts or service your unit.

AOS Bath Team

AOS Bath Team