Top Gas Hot Water System Choices for Efficient Home Heating

If you’re in the market for a hot water solution, a gas hot water system offers convenience and efficiency. In this article, we’ll explore the options available and what you need to know to make a well-informed decision for your household.

Key Takeaways

  • Gas hot water systems, utilizing gas storage, instantaneous, and solar options, provide efficient hot water delivery, saving space and energy while meeting diverse homeowner needs.

  • Offering superior energy efficiency and eco-friendliness compared to electric heaters, gas hot water systems minimize energy consumption, reduce greenhouse gas emissions, and are generally cost-effective due to lower running costs.

  • Maintenance and professional installation are crucial for the optimal performance of gas hot water systems, which must be sized correctly based on household needs and should be regularly serviced to ensure efficiency and longevity.

Understanding Gas Hot Water Systems

Gas hot water system

Often referred to as gas hot water heaters, gas hot water systems are engineered to provide hot water whenever it’s needed. These systems utilize gas as their primary fuel source, making them a favored choice for home heating.

Diverse in design, these systems come in various categories such as gas storage, gas instantaneous (also known as continuous flow), and gas solar hot water systems. Their ingenious design allows them to deliver hot water instantly, save space, and potentially provide a continuous hot water supply, efficiently meeting diverse homeowner needs.

Types of Gas Hot Water Systems

Storage and instantaneous systems are the two primary categories of gas hot water systems. These systems have a superior energy efficiency compared to electric hot water heaters.

A gas storage hot water system uses a gas burner located under an insulated tank to heat water. It’s an ideal choice for large families with high hot water demand due to its rapid heat recovery time.

Conversely, an instantaneous gas hot water system delivers hot water instantly when the tap is turned on by igniting the gas burner and distributing hot water through a heat exchanger. This makes it an efficient alternative to electric hot water systems and solar hot water systems.

How Gas Hot Water Systems Work

Gas hot water systems function by using a gas burner placed beneath the storage tank or leveraging a secondary heat exchanger to capture heat from exhaust gases, thereby heating water efficiently with a gas hot water heater. In this process, the gas hot water unit plays a crucial role in providing hot water to households and businesses.

Storage hot water systems maintain a reservoir of hot water for immediate use, while continuous hot water systems, also known as instantaneous hot water systems, offer an endless supply by heating water as it’s needed. The heat exchanger in a gas hot water system plays a pivotal role, especially in continuous flow units, enabling rapid water heating and optimizing energy transfer and efficiency.

Advantages of Gas Hot Water Systems

Energy efficiency of gas hot water systems

Also known as gas water heaters, gas hot water systems showcase excellent energy efficiency by heating water only as needed, thus minimizing overall energy consumption and preventing power wastage. This characteristic gives gas water heater an edge over electric water heaters, which may experience energy loss during periods of inactivity.

In addition to their energy efficiency, gas hot water systems are also more environmentally friendly than electric heaters. Thanks to their superior energy efficiency, they contribute to a reduction in greenhouse gas emissions, making them a more sustainable solution for residential heating.

Energy Efficiency

Gas hot water systems surpass their electric counterparts when it comes to energy efficiency. They exploit gas only when required, reducing energy consumption considerably. Tankless gas hot water systems, in particular, can enhance average energy efficiency by 22% and outperform traditional tank water heaters by 8 to 34% in efficiency.

These systems also employ a refrigeration cycle to extract heat from the air to heat the water, further boosting their energy efficiency. Gas hot water systems utilize natural gas or propane, which is often more cost-effective than electricity. They also generate fewer greenhouse gas emissions and offer energy-efficient models in both storage and instant styles.


Mainly due to lower running costs, gas hot water systems are generally perceived as more cost-effective than their electric counterparts.

Switching to a gas hot water system can lead to substantial reductions in energy expenses. Although electric heat pumps and solar hot water systems may offer superior long-term savings despite higher initial investments, households could potentially save an additional $800 annually by fully switching to gas cooking, heating, and hot water.

Eco-Friendly Heating Solution

Eco-friendly gas hot water system

Gas hot water systems have several environmental benefits, including:

  • Emitting minimal greenhouse gases

  • Contributing to environmental sustainability

  • Reducing greenhouse gas emissions by utilizing more efficient models

  • Decreasing the demand for hot water

Utilizing natural gas for hot water systems offers several benefits:

  • Decreases carbon emissions

  • Minimizes energy consumption

  • Reduces utility expenses

  • Cost-effective and eco-friendly fuel option

  • Contributes to energy conservation by utilizing a refrigeration cycle to extract heat from the air

  • Improves energy efficiency

  • Reduces greenhouse gas emissions

  • Provides rapid hot water supply

These advantages make natural gas a great choice for heating water.

Selecting the Right Gas Hot Water System for Your Home

Selecting the right gas hot water system

Various factors to consider when selecting the right gas hot water system for your home include:

  • The number of people and bathrooms in your household

  • The age of your household

  • Simultaneous hot water use by appliances

  • Bathing frequency

  • The local climate

Taking these factors into account will help you choose the most suitable gas hot water system for your needs.

Both indoor and outdoor models of gas hot water systems are available, offering homeowners the flexibility to choose the most suitable option. Indoor models typically offer better energy efficiency and faster heat recovery, while outdoor models can be more cost-effective but may have higher greenhouse gas emissions if not powered by renewable energy sources.

Sizing Your Gas Hot Water System

The size of the gas hot water system is of significant importance. It is influenced by factors such as:

  • Family size

  • Home size

  • Water usage

  • Whether the system operates during off-peak or on-peak hours

Water usage has a substantial impact on the required size of a gas hot water system. In colder climates, a larger system may be necessary to meet the increased demand for hot water. Conversely, in sunny areas with ample solar radiation, a solar hot water system can be more efficient.

Indoor vs. Outdoor Models

Choosing between indoor and outdoor models of gas hot water systems depends on your specific needs and preferences. Here are some factors to consider:

  • Indoor systems have a significant initial cost.

  • Indoor systems have higher operational expenses.

  • Indoor systems are susceptible to rust if not adequately maintained.

  • Indoor systems may experience heat loss over time.

On the other hand, outdoor models have their own set of disadvantages including:

  • Higher LPG costs compared to natural gas

  • No hot water in a blackout due to electric ignition

  • Higher purchase and installation costs

  • Reduced effectiveness in shaded areas

  • The potential need for multiple units for larger homes or higher hot water demand.

Leading Brands and Models

Choosing a reliable and effective gas hot water system involves considering brands like Rheem, Rinnai, Dux, Bosch, and Aquamax. Models such as Joolca HOTTAP, Dux Prodigy 4, Dux Always Hot Continuous Flow, Smarttek Black Smart Hot Water System, Rinnai Infinity Range, Rheem, Aquamax, Solahart, Chromagen, and Vulcan are highly regarded in the market for providing reliable hot water.

Comparing these models using model comparison charts from SA Hot Water or Cheapa Hot Water can help you make an informed decision.

Installation and Maintenance of Gas Hot Water Systems

Professional installation of gas hot water system

Correct installation of your gas hot water system is paramount. It ensures proper ventilation and an ideal location for the system, both of which are critical for its optimal performance.

To operate a gas storage hot water system, it is essential to have a gas connection and a flue vent or pipe if the system is placed indoors. The installation process takes on average two to three hours and involves filling and testing the tank for leaks, ensuring all plumbing and electrical work is done by licensed tradespeople, adhering to the manufacturer’s installation instructions, and disconnecting gas and water lines before removing the old system.

Professional Installation

A professional installation promises to maximize your system’s efficiency and lifespan. It ensures proper installation with a comprehensive understanding of plumbing and electrical systems, resulting in reduced energy consumption, quicker heating, and optimal performance.

Self-installation of a gas hot water system can result in:

  • Home damage

  • Expensive repairs

  • Water leaks

  • Inefficient heating

  • Serious hazards such as carbon monoxide leaks and injury

A professional installer is required to have completed a three-to-four-year plumbing apprenticeship and obtained the necessary gas fitting licenses and certificates.

The average installation cost for a gas hot water system ranges from $200 to $400, and may vary depending on the specific system and the location of installation.

Regular Maintenance

Consistent maintenance is key to improving the performance, energy efficiency, and overall lifespan of your gas hot water system. Maintenance procedures involve:

  • Conducting a comprehensive inspection of components

  • Examining the anode rod

  • Cleaning air filters

  • Inspecting condenser and evaporator coils

  • Testing the pressure and temperature relief valve

  • Checking the cold water expansion valve

  • Inspecting for leaks or drips

  • Examining the sacrificial anode

  • Verifying thermostat settings

It is recommended to service a gas hot water system every 6 months, particularly in regions with hard water.

Common Issues and Troubleshooting Tips

You may face a few common problems with your gas hot water system. These include inadequate supply of hot water, fluctuations in water temperature, and gas leaks.

Inadequate hot water supply can be due to a defective diaphragm, improper installation of a storage tank that cannot meet demand, undersized gas bottle, a defective showerhead, or a faulty dip tube. Fluctuations in water temperature can be attributed to insufficient gas supply, inadequately-sized water heater, or a faulty pressure-balancing valve.

Gas leaks can be detected by the smell of gas, a hissing sound, dead house plants, pipe damage, or physical symptoms.

Insufficient Hot Water

The issue of an inadequate hot water supply can be frustrating. It can stem from various factors such as:

  • a defective diaphragm

  • improper installation of a storage tank that cannot meet demand

  • undersized gas bottle

  • a defective showerhead

  • a faulty dip tube.

The thermostat setting in a gas hot water system plays a crucial role in maintaining the desired water temperature. It continuously monitors and adjusts the water temperature to ensure that hot water is readily available when needed.

Fluctuating Water Temperature

Factors like insufficient gas supply, an undersized water heater, or a malfunctioning pressure-balancing valve can lead to fluctuating water temperature in your gas hot water system.

A malfunctioning thermostat can result in varying water temperatures. When the thermostat fails to regulate the temperature accurately, it can lead to inconsistent supply of hot water.

Gas Leaks and Safety Concerns

A gas leak is a grave issue requiring immediate attention. Typical indicators of a gas leak encompass a rotten egg or sulfur smell, hissing or whistling sounds near the water heater, and physical damage to the water heater.

In the event of a suspected gas leak, it is important to take the following steps:

  1. Promptly evacuate the premises with your family and pets.

  2. Ventilate the building by opening doors and windows.

  3. Refrain from igniting any flames or electrical switches.

  4. Contact your gas supplier or the fire department.

  5. Do not re-enter the premises until a qualified service technician has addressed the leak.


Gas hot water systems are an efficient, cost-effective, and eco-friendly solution for home heating. Choosing the right system requires considering various factors such as the number of people and bathrooms in your home, the age of your household, the simultaneous use of hot water by appliances, the frequency of baths, and the climate of your location. Regular maintenance and professional installation are crucial for optimal performance and longevity of the system. Be aware of common issues such as inadequate hot water supply, fluctuations in water temperature, and gas leaks, and know how to troubleshoot them.

Frequently Asked Questions

What are the disadvantages of a gas hot water system?

Gas hot water systems have higher upfront and maintenance costs compared to electric ones, even though they result in lower energy bills. Consider these factors before making a decision.

Is gas hot water worth it?

Yes, gas hot water systems are worth it because they are more energy efficient and heat water faster than electric models, resulting in lower energy bills in the long run.

Is it cheaper to heat water with gas or electric?

Heating water with gas is generally cheaper than using electric. Gas offers lower running costs and smaller bills compared to electricity.

Is gas hot water cheaper than electric?

Yes, gas hot water is generally cheaper than electric due to the lower running costs and smaller bills, and it is not affected by time-of-use power tariffs. Just keep in mind that gas can run out.

What are the different types of gas hot water systems?

The different types of gas hot water systems are gas storage, gas instantaneous (or continuous flow), and gas solar hot water systems. Choose the type that best suits your needs.