Instant Gas Hot Water Sydney
- NSW Licence 339748C
- 5 ⭐️ Rated on Google
- Based in Seven Hills
- Call 1300 301 354
See your installed price online, then we fit it.
Compare instant gas hot water units by size and brand in our price tool, with the installation in a fixed price. A licensed gas fitter does the work. A like-for-like swap usually takes about three hours.
Hot water replacement prices, upfront
Compare installed prices for gas and electric systems. No name, email or number needed.
or call 1300 301 354
On this page: Our installations · What size you need · Costs · Questions
Some of our instant gas installations
Baulkham Hills: a leaking tank swapped for a wall-mounted unit
The 130 litre Rheem gas storage tank was leaking. The owners wanted an instant unit on the wall instead, to save space and have hot water on demand. We took the tank out and fitted a Rinnai Infinity B26, preset to 50°C, with new copper gas and water lines.
Baulkham Hills: a 20-year-old Rinnai replaced like for like
After 20 years, a Rinnai Infinity 26 stopped working. A new Rinnai B26 went straight into its place, with no new valves or copper work. It comes preset to 50°C, so no tempering valve was needed. That made it the most economical way to get the hot water back.
Lalor Park: a Thermann 26R in place of an old Rinnai
Another Rinnai Infinity 26 had given more than 20 years of service. We replaced it with a new Thermann 26R instant gas unit and fitted new gas and water valves.
What customers say about our hot water work
“Johnny from All Day Plumbing did a great job replacing our old hot water system. He arrived on time, explained everything clearly and had the new unit installed quickly. The workmanship was excellent and everything was left clean and tidy. Highly recommend Johnny.”
Mate K., Google review, 2026
“David and Luke came out and replaced my hot water system. Quick, efficient and easy to deal with”
Olivia B., Google review, 2026
How instant gas hot water works
An instant gas unit, also called continuous flow, heats water as it passes through. There is no storage tank. The burner fires when a hot tap opens and stops when it closes.
Because it heats on demand, it does not run out the way a tank can. What it can deliver at once depends on its flow rate, measured in litres per minute. Outdoor models mount on an outside wall, and indoor models need a flue to take the exhaust outside.
What size do you need?
The flow rate you need depends on how many hot taps and showers run at the same time. Rinnai’s sizing guide rates a 26 litre per minute unit for one to three showers at once in a warm climate. For a cool climate it gives one to two and a half, because colder water needs more heating.
A one-bathroom home needs less flow than a household running two showers and the washing machine together. Before we install, we confirm the size, the position and the gas and power supply with you.
What your home needs first
- Natural gas or LPG. Mains gas is not available everywhere. For a new mains connection, you apply to the gas network or a retailer, and the network fits the meter. The pipework from the meter to the appliances is gas fitter’s work. More on gas line installations.
- Gas pipes that can carry the load. An instant unit draws a lot of gas while it runs. The pipe size has to allow for it and for every other gas appliance in the house.
- A power point. Most models need an earthed power point beside the unit, so they stop during a blackout.
- A compliant spot. The flue outlet must sit set distances from windows, doors and other openings.
- Safe water in the bathroom. Hot water at bathroom outlets must be no hotter than 50°C. A unit preset to 50°C, or a tempering valve, takes care of it.
Natural gas or LPG?
Instant units are made for natural gas or for LPG, and the unit has to match the gas at your home. A home without mains gas can run one on LPG cylinders. We work on both. For LPG work, the gas fitter fits a compliance plate and gives you a certificate of inspection.
Switching from a tank or from electric
Swapping a storage tank for an instant unit frees up space and ends running out of hot water mid-shower. From a gas tank, the gas pipe may need upgrading for the instant unit’s higher gas rate. From an electric tank, the gas supply and pipework come first, and we do that gas work too. We check all of it before we confirm the price. More on hot water system installation.
What it costs
The price tool on this page compares instant gas units by size and brand, with the installation included in a fixed price. You see the price before you book. Taking the old system away is part of the job. Anything extra, such as a bigger gas pipe, is quoted before it starts. A new mains gas connection is charged by the gas network, upfront and separately from our price. Our article on what an instantaneous hot water system costs explains what changes the price.
How an installation runs
- Check your price in the tool, then book online or call 1300 301 354.
- You get an arrival window, and the plumber lets you know when they are on the way.
- We confirm the size, position, gas and power on site before we start.
- A licensed gas fitter fits the unit and sets the temperature.
- We test the gas connections and the hot water before we leave, and take the old unit away.
Common problems with instant units
- An error code on the controller. Note the code before you call, as it points to the fault.
- No hot water after a power cut. If the unit needs power, check its power point and circuit breaker.
- Water turns cold when another tap opens. The unit may be at its flow limit, or a part may be failing.
- A unit that will not light. Check that your other gas appliances work, in case the gas supply is off.
We repair instant units as well as storage tanks. See hot water repairs.
Running costs
How much gas an instant unit uses depends on the flow, the temperature it is set to and how long the taps run. Shorter showers and a sensible temperature cut gas use. Our article on how much gas an instant system uses goes through the numbers.
Looking after an instant unit
- Have it serviced as often as the maker’s manual says. Jemena says gas appliances need regular servicing to run safely and efficiently, and we service hot water systems.
- Keep the area around the unit clear, so nothing blocks the flue outlet or the air around it.
- Write down any error code that appears, and when it happened.
Why All Day for instant gas hot water
- Installed prices by size and brand, online before you book.
- Gas work by a licensed gas fitter under NSW contractor licence 339748C, and we are fully insured.
- 20+ years’ experience in the trade.
- A warranty on every job.
- Based in Seven Hills, working across the Sydney metro area.
Hot water replacement prices, upfront
Compare installed prices for gas and electric systems. No name, email or number needed.
or call 1300 301 354
Instant gas hot water questions
Most do. They need a power point for their controls, so they stop during a power cut. For the detail, read do instantaneous gas hot water systems need electricity.
No. It heats water as it flows, so there is no tank to empty. If too many outlets run at once, the flow or the temperature at each can drop, which is why the flow rate matters.
Often, yes. It depends on the unit’s flow rate and how cold the incoming water is. A 26 litre per minute unit is rated for one to three showers at once in a warm climate. A smaller unit may suit only one.
Some models are made for indoor installation, with a flue to take the exhaust outside. Outdoor models mount on an outside wall instead.
It depends on your home. An instant unit heats water only when you use it and takes up less space. A tank keeps a store of hot water ready. Our guide to instant versus storage systems compares them.
The price tool shows the brands and sizes we install, including Rinnai, Rheem, Dux and Thermann. Our article on choosing an instantaneous gas system compares popular models.
Yes, when the home has gas or can be connected, and its gas pipes can carry the load. We check the gas supply, the position and the power point first, and we do the gas line work too.
Controllers in bathrooms must not be able to select more than 50°C, to cut the risk of burns. NSW applies the same 50°C limit to bathroom outlets whenever a water heater goes in or is replaced.
A like-for-like swap usually takes about three hours, and same-day installation is often possible. Changing from a tank, or adding gas pipework, takes longer. We confirm the timing when you book.
Yes. In NSW, gasfitting work needs a licence, and connecting an instant gas unit is gasfitting work. On mains gas, the gas fitter lodges a certificate of compliance after the job.
Areas we cover
We install instant gas hot water across the Sydney metro area from our base in Seven Hills. Hills District homes can also see hot water in the Hills District, and every other area is on our locations page.
Ready for instant gas hot water? Call 1300 301 354 and we’ll help you choose the right size.
Rather do it online? Check your price in the tool above, then book.