Gas Heater Installation Guide: Costs, Process and When to Replace Your Old Unit

Whether your old gas heater has finally given up or you are upgrading to a newer, more efficient model, understanding what is involved in a gas heater installation helps you plan the process and budget accurately. As a trusted plumber Sydney homeowners rely on for gas installations, Hero Plumbing completes hundreds of gas heater installations and replacements across Sydney every year. This guide covers costs, the installation process, how long it takes, and the key signs that replacement is overdue.

How much does it cost to install a gas heater in Sydney?

Gas heater installation costs in Sydney vary depending on several factors:

• System type: A flued gas space heater costs differently to install than a continuous flow hot water system or a ducted gas heating system. Each requires different flue configurations and gas connection work.
• Like-for-like replacement vs new installation: Replacing a like-for-like unit in the same location is the most affordable option. Installing a new unit in a different location, or creating a new gas connection from scratch, adds significant cost.
• Gas connection: If your home is already connected to natural gas, the installation cost is lower. If a new gas meter and supply line are needed, these add to the overall project cost.
• Flue or venting requirements: Flued heaters require appropriate flue routing to an exterior wall or roof. Complex flue installations increase the labour cost.
• Brand and model: Premium brands and larger capacity units cost more than entry-level models. However, a higher upfront cost often means lower running costs and a longer warranty period.

For an accurate installation cost specific to your property, call Hero Plumbing for a no-obligation quote. We service all major brands including Rinnai, Rheem, Everdure, Paloma, and Omega Altise.

How long does gas heater installation take?

A straightforward like-for-like replacement of a gas heater (same location, existing gas connection, standard flue configuration) typically takes 2 to 4 hours. A more complex installation involving a new gas connection, different location, or ducted system can take most of a day. Your installer will give you a timeline before starting work.

The gas heater installation process: what to expect

1. Site assessment: A licensed gas fitter visits to assess the installation location, gas supply, flue routing options, and ventilation requirements before quoting.
2. Unit selection: Your installer helps you choose the right brand and model for your home’s size, layout, and gas supply capacity.
3. Removal of old unit: If replacing an existing heater, the old unit is safely disconnected, the gas supply capped, and the appliance removed.
4. New unit installation: The new heater is positioned, the flue is connected, gas connections are made, and the unit is mounted securely.
5. Commissioning and testing: The gas fitter pressure-tests all connections, lights the unit, verifies correct combustion, checks CO levels, and confirms all safety controls are working.
6. Certification: In NSW, all gas appliance work must be certified by a licensed gas fitter. Your installer provides a certificate of compliance for the work.

Signs it is time to replace your old gas heater

• The unit is more than 12 to 15 years old
• You are spending more on repairs than the unit is worth
• Energy bills have increased without a corresponding change in use
• The heater is struggling to maintain temperature or takes much longer to heat the space
• There are repeated pilot light, ignition, or burner faults
• The unit is producing unusual smells, sounds, or visible sooting
• A gas safety inspection has flagged concerns with the current unit

Read our full guide on whether to repair or replace your water heater and what you should know about gas heater servicing for more context.

Why professional installation matters

Gas appliance installation in NSW is strictly regulated. Only a licensed gas fitter is legally permitted to connect or disconnect a gas appliance, test gas connections, and certify the work. Unlicensed gas work is illegal, voids insurance policies, and creates a serious safety risk. Hero Plumbing’s gas fitters are all fully licensed, carry public liability insurance, and provide a written certificate of compliance for every installation.

Benefits of replacing an old gas heater

• Lower running costs from improved energy efficiency ratings
• Manufacturer’s warranty (typically 2 to 5 years on parts, 5 to 10 years on heat exchangers for quality brands)
• Improved safety features including improved CO detection and safety shutoffs
• Better heating performance and faster warm-up times
• Peace of mind knowing the appliance meets current Australian Standards

Book a gas heater installation in Sydney

Hero Plumbing carries stock of all major gas heater brands and can often carry out replacements same-day or next-day. We also provide gas heater servicing for all brands through our dedicated gas heater service team in Sydney. Call us today or book online for an honest, no-obligation quote.