Gas Heaters vs. Storage Water Heaters: 6 Key Considerations

Choosing the right water heater for your home in Singapore can be challenging as it involves weighing factors such as cost, efficiency, safety, and installation requirements. If you are looking to install a water heater, this article provides a comparative analysis of gas and electric water heaters to help Singaporean homeowners make an informed decision based on their specific needs and household conditions.

1. Efficiency and Cost

Gas Heaters: Gas heaters are known for their high energy efficiency and cost-effectiveness, especially beneficial for larger families or households with high hot water demands. They heat water faster and usually have lower operational costs because gas prices tend to be lower than electricity prices in many areas. For instance, using a Macro MA-20ODP gas heater to heat 100 litres of water from 28°C to 60°C, with town gas priced at SGD 0.23 per kWh, costs SGD 1.19 and can be accomplished within 10 minutes.

Electric Storage Heaters: Electric heaters, while slightly less efficient in terms of energy usage and having a longer delivery time, provide consistent heating and can be more economical for smaller households or those with lower demands for hot water. The cost of electricity versus town gas is SGD 0.32 vs SGD 0.23, and fluctuating. Gas may be cheaper today than electricity, but this can change over time. For example, the cost of using a Rheem EHG55S to heat 100L of water from 28°C to 60°C in Singapore, where the cost of town electricity is SGD 0.32 per kWh, is SGD 1.32, which is 11% higher than gas. This process will take about an hour.

2. Shower Experience

Gas Heaters: In the Singapore context, only the instantaneous or tankless version is available. Changes in water pressure and flow directly affect the temperature of the hot water. Since most gas heaters act as a central heating system, turning on the tap in another bathroom can cause a drastic drop in water temperature, causing a brief discomfort to the user.

Electric Storage Heaters: To comply with the code of practice, among other things, there is a need to install a device like a double-check valve to prevent backflow. During heating, the pressure in the vessel can rise to as high as 118 psi before activating the pressure relief valve as part of the safety measure. High pressure coupled with stored hot water allows a consistent flow rate and temperature throughout the shower, whether the heater is shared or not. This gives the 5-star hotel shower experience.

3. Safety and Maintenance

Gas Heaters: These heaters require strict adherence to safety protocols to mitigate risks such as gas leaks and carbon monoxide exposure. They require regular maintenance and professional installation to ensure safe operation. A notable clause for testing gas appliances under the Gas Supply Regulations: 21.—(1) Any person who carries out any installation, maintenance, or repair of a gas appliance at a time when gas is being supplied to the premises in which the gas appliance is installed shall, immediately after completion of such installation, maintenance, or repair, test the gas appliance and its connection to the gas installation to check that: (a) the gas appliance is safe to be used; (b) the connection of the gas appliance to the gas installation is gas-tight; and (c) the work is in compliance with these Regulations. (2) If, on completion of the tests referred to in paragraph (1), it is found that the gas appliance is safe for use, the person performing the tests shall issue a written statement certifying the gas appliance is safe for use. (3) No person shall use any gas appliance that has not been certified safe for use. (4) Any person who contravenes paragraph (1), (2), or (3) shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $5,000.

Electric Heaters: Electric heaters offer a safer alternative as they do not involve combustion and consequently do not produce harmful gases. They are typically easier to maintain but still require periodic checks and component replacements to ensure proper function.

4. Installation and Flexibility

Gas Heaters: For larger gas heaters, like those with a 16L/m or 20L/m capacity, installation is limited to outdoors, such as on an aircon ledge without a flue. However, indoor installation is possible with the implementation of a flue. Gas water heaters with a gas consumption rating not exceeding 42.2 MJ/h (10L/minute flow rate), when installed in well-ventilated kitchens, do not require flue installations.

Electric Heaters: Electric heaters excel in installation flexibility. Since they do not require venting, they can be placed in various locations within a home. This makes them particularly suitable for internal spaces in high-rise apartments and other urban dwellings where external venting is challenging. According to regulations, it is not allowed to be installed under a waste pipe, and a drainpipe connected to the floor trap is needed to connect to the pressure relief valve. Ensuring an adequate electrical supply is often challenging, as there is a need for a 20A power supply. In some older HDB units with a maximum supply of just 32A, this can be particularly challenging.

5. Environmental Impact

Gas Heaters: In Singapore, gas heaters generally have a lower carbon footprint than electric heaters, as the composition of Town gas includes 40 to 60% hydrogen, unlike natural gas, which consists of over 90% methane.

Electric Heaters: The environmental impact of electric heaters largely depends on the source of the electricity. If the electricity is derived from renewable resources, electric heaters can be an environmentally friendly option. Conversely, if the electricity is generated from non-renewable resources, their environmental benefit is diminished.

6. Long-Term Durability and Life Expectancy

Gas Heaters: The durability of gas heaters depends on the brand. Typically, well-made gas heaters like those from Rinnai or Macro have a lifespan of 10 years or more, unlike brands like Ferroli, which may experience issues such as CO emission from incomplete combustion and heat exchanger leaks after 2 years.

Electric Heaters: These heaters tend to have fewer moving parts, which can mean less wear and tear over time. However, components like heating elements may need to be replaced periodically, especially in areas with hard water.

Conclusion

The decision between a gas and an electric water heater in Singapore should consider individual usage patterns, installation possibilities, safety concerns, and environmental impacts. Gas heaters are suited for larger households with extensive hot water needs, offering efficiency and cost savings. In contrast, electric heaters are ideal for smaller homes or apartments, providing ease of installation and enhanced safety. Homeowners should carefully evaluate these factors to choose the most suitable Singapore water heater for their needs.