Pricing Continuous Flow Hot Water?
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Typical Costs
Gas continuous-flow (supply)$900-$2,200
Gas unit installed (swap)$1,200-$2,800
Larger or new gas run$2,500-$3,500+
Electric continuous-flow$1,000-$2,500
Tempering valve$250-$600
Gas or flue work$300-$1,200
These are indicative 2026 NSW estimates only. The unit size and flow rate, the fuel, the gas and flue work, the tempering, and the installation all drive the final price; a straightforward gas swap costs far less than a larger unit needing a new gas run.
Continuous Flow Hot Water Costs NSW 2026 - Get Free Quotes
A continuous-flow hot water system in NSW commonly costs around $1,200 to $3,500 supplied and installed, with a straightforward gas swap from about $1,200 and a larger unit needing a new gas run higher. A continuous-flow system, also called instantaneous or on-demand, heats water only as you use it, with no storage tank, giving endless hot water and saving the standing heat loss of a tank. It matters because the unit must be sized to your peak flow, installed by a licensed plumber, with gas and flue work by a licensed gasfitter, and fitted with tempering so water is delivered safely. This guide explains what continuous-flow is, gas versus electric, sizing and flow rate, what is involved, the process, how long it takes, what affects the cost, Sydney and regional pricing, what to look out for, and what to look for in a quote. Post your job on The Quote Yard to get quotes from licensed hot water and plumbing trades across New South Wales.
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At a Glance - Continuous Flow Hot Water NSW 2026
| Element | Typical Cost | Basis | Notes |
|---|---|---|---|
| Gas continuous-flow (supply) | $900-$2,200 | Unit only | By flow rate |
| Gas unit installed (swap) | $1,200-$2,800 | Like swap | Most common |
| Larger or new gas run | $2,500-$3,500+ | Extra work | New line |
| Electric continuous-flow | $1,000-$2,500 | Small units | Limited flow |
| Tempering valve | $250-$600 | Compliance | Required |
| Gas or flue work | $300-$1,200 | As needed | Gasfitter |
Cost Depth: What Drives Continuous Flow Hot Water Pricing in NSW
The cost of a continuous-flow hot water system in NSW is shaped by the unit size and flow rate, the fuel, the gas and flue work, the tempering, and the installation. The unit and the installation type are the biggest drivers, because a straightforward like-for-like gas swap, reusing the existing gas and water connections, is far simpler than a larger unit needing a new gas run, so a swap commonly lands around $1,200 to $2,800 while a larger install with new gas or flue work runs $2,500 to $3,500 or beyond. The flow rate counts, as a higher flow-rate gas unit that can run several outlets at once costs more than a small one, with the unit alone at roughly $900 to $2,200. The gas and flue work matters where a new gas line or flueing is needed, at about $300 to $1,200. A tempering valve is a required compliance cost at roughly $250 to $600. Electric continuous-flow units are cheaper but limited in flow, suiting a single outlet. Because the licensed plumbing, gasfitting, and tempering cannot be skimped, a clear quote that separates them from the unit is the one to trust.
Continuous-flow hot water installation must be carried out by a licensed plumber, with gas and flue work by a licensed gasfitter and any electrical work by a licensed electrician, and a tempering valve is required under AS 3500 so water is delivered at a safe temperature to fixtures. Plumbing, gasfitting, and electrical licensing come from NSW Fair Trading, work health and safety from SafeWork NSW, plumbing and product standards from Standards Australia, energy efficiency and rebates from Energy NSW, and general trade information through Service NSW. Never save by skipping licensed work or tempering on a continuous-flow system.
Continuous Flow Hot Water Costs in NSW
A continuous-flow system heats water only as you use it, with no storage tank. In NSW a straightforward gas swap is commonly $1,200 to $2,800, while a larger unit needing a new gas run runs $2,500 to $3,500 or more. Because the unit, the flow rate, and the gas work drive most of the cost, the total depends heavily on the job. A simple swap is one thing while a new gas run is another.
What moves the price most is the unit and the gas work. The unit counts. The peak flow rate matters a lot. The gas work varies. Telling the plumber your household size and what you have now is what lets them quote the job.
A licensed plumber installs the unit, with a gasfitter for the gas and flue, and it is sized to your peak flow, which is why it draws on hot water services. They mount the unit, connect the water and gas, flue it, and fit the tempering, which for many homes is a form of hot water system installation. Endless, on-demand hot water is the real goal. The unit looks compact once fitted, but the sizing, the gas, and the tempering all matter. Getting it right means hot water that never runs out and is delivered safely.
A continuous-flow system is chosen for endless hot water, for saving space, and for efficiency. Because it never runs out, takes up little room, and wastes no standing heat, it suits many homes, which is why it matters, covered below. The endless supply, the space saving, and the efficiency are the main draws. It uses licensed trades. The capacity is matched to your flow.
The most important thing to understand is that the unit must be sized to your peak flow. Because a too-small unit cannot run several hot taps or showers at once, the flow rate must match your busiest moment, which is covered below in the instantaneous hot water system installation section. This is the flow point. In practice, it is matched to the busy peak. Never run short.
The fuel sits alongside the flow in the choice. Because gas continuous-flow gives high flow while electric is limited, the fuel shapes what the system can do, related to gas hot water system installation. This is the fuel point. Gas gives a high and generous flow. Electric is limited.
The simplest way to think about the cost is the unit, the install, and the gas work. The unit means the flow rate and fuel. The install means a swap or a new location. The gas work means reusing or running new gas and flue. Combine the unit, the install, and the gas work and you have a realistic figure.
A clear picture of your home and its hot water use is the sensible basis for a quote. The plumber needs to know your household size, your fixtures, and what you have now to size the job, which this work needs for an accurate quote, related to plumbing services. A quote with no site look is a rough guess as a rule. Generally, a clear picture gives a far more reliable price. In practice, knowing your peak use before you ask helps.
What It Covers
A continuous-flow installation covers the sizing, the unit, the connections, the tempering, and the commissioning. A licensed plumber and gasfitter size the unit, mount it, connect the water and gas, flue it, fit the tempering, and commission it. It draws on hot water services and is a form of hot water system installation. Endless, on-demand hot water is what it delivers. The aim is a unit sized and installed to run without fail.
The unit is sized to your peak flow. The flow rate is matched to how many outlets you may run at once, related to instantaneous hot water system installation. This is the sizing. It is matched to your peak use. Right flow.
The water and gas go in via licensed trades. A plumber and gasfitter complete the pipework and flueing to standard, related to plumbing services. This is the connection. In practice, skilled licensed trades always do the work. Done legally.
The tempering valve is fitted for safe delivery. A tempering valve delivers water at a safe temperature to the fixtures, related to hot water tempering valve installation. This is tempering. It ensures safe delivery at the taps. Rules met.
The finished unit is commissioned and handed over. It is tested, set, and signed off ready to use, related to hot water system installation. This is commissioning. The whole unit is then thoroughly tested. Then running.
It is worth remembering that a continuous-flow unit is compact and frees up the space a tank would take. A small wall-mounted unit, often outside, removes the bulky tank and gives back floor or cupboard space, related to hot water system installation. A wall unit saves you real space. A tank takes room. It is worth the saving. Remembering that a continuous-flow unit is compact and frees up the space a tank would take, since it wall-mounts, is a real practical benefit.
It is worth knowing that continuous-flow gives endless hot water, so the shower never goes cold. Because it heats as you go rather than emptying a tank, a long shower or a run of showers stays hot throughout, related to hot water services. Endless supply keeps the whole shower hot. A tank can empty. It is worth the endless flow. Knowing that continuous-flow gives endless hot water, so the shower never goes cold, since there is no tank to empty, is one of its main draws.
It is worth thinking about converting a storage tank to continuous-flow for endless water and space. Removing the tank and fitting a compact wall unit gives back the tank's space and the endless supply, though it adds re-plumbing, related to hot water system installation. A conversion gains space and endless flow. It adds a little work. It is worth weighing up. Thinking about converting a storage tank to continuous-flow for endless water and space, since it frees the tank's spot, is worth considering at replacement time.
It is worth remembering that continuous-flow avoids the standing heat loss of a storage tank. Because it only heats water when a tap is opened, it does not keep a tank hot around the clock, which can save energy, related to hot water services. No standing loss can really save energy. A tank loses heat constantly. It is worth the efficiency. Remembering that continuous-flow avoids the standing heat loss of a storage tank, since it heats only on use, is one reason it is efficient.
It is worth considering that continuous-flow pairs well with a modern, water-efficient home. With efficient fixtures and no standing tank loss, a well-sized gas unit gives endless hot water at a reasonable running cost, related to hot water services. Efficient fixtures suit continuous-flow really rather well. Wasteful ones strain it. It is worth pairing them. Considering that continuous-flow pairs well with a modern, water-efficient home, since both save on waste, is worth bearing in mind.
It is worth being aware that continuous-flow suits homes that want endless hot water and a compact unit. For households that dislike running out of hot water and want to reclaim the space a tank takes, a well-sized gas unit is ideal, related to instantaneous hot water system installation. Endless supply and a small unit appeal. A tank offers neither. It is worth weighing up. Being aware that continuous-flow suits homes that want endless hot water and a compact unit, since it never empties, is worth bearing in mind at replacement time. The governing standards are available through Standards Australia.
What Continuous Flow Is
A continuous-flow system heats water instantly as it passes through the unit. There is no tank, so water is heated on demand only when a tap is opened, related to instantaneous hot water system installation. This is the idea. There is no storage tank at all. Heated on demand.
It gives endless hot water that never runs out. Because it heats as you go, it cannot empty like a tank, so the shower stays hot, related to hot water services. This is endless. There is no tank that can empty. Always hot.
It is compact and mounts on a wall, saving space. A small unit on an external or internal wall frees up the room a tank would take, related to hot water system installation. This is compact. It mounts neatly on an external wall. Saves space.
It wastes no standing heat, so it can be efficient. With no stored water kept hot around the clock, it avoids the standing loss of a tank, related to hot water services. This is efficiency. It has no standing heat loss at all. Heats on use.
It is most commonly gas, though electric units exist. Gas continuous-flow gives high flow, while electric units suit a single outlet, related to gas hot water system installation. This is the fuel. It is most commonly a gas unit. Electric for less.
It is worth weighing gas against electric continuous-flow, since they suit very different demands. Gas gives high flow for a whole home, while an electric unit is limited and suits a single outlet, related to electric hot water installation. Gas suits a busy home, while electric suits a small point of use. It is worth weighing both.
It is worth checking whether you have mains gas before choosing a continuous-flow system. Where there is mains gas a high-flow gas unit is ideal, but with only bottled LPG or no gas the options and running costs change, related to gas fitting. Mains gas suits a whole home well. No gas points to LPG or electric. It shapes the choice. Checking whether you have mains gas before choosing a continuous-flow system, since it drives the options, is a sensible first step.
It is worth being aware that an electric continuous-flow unit for a whole home can need a heavy power supply. Heating a high flow of water electrically draws a great deal of power, so a dedicated circuit or supply upgrade may be needed, related to electrical services. A single-outlet electric unit is fairly modest. A whole-home one draws heavily. It is worth checking supply. Being aware that an electric continuous-flow unit for a whole home can need a heavy power supply, since the draw is high, is worth confirming with an electrician.
It is worth understanding that the flue and clearances matter for a gas continuous-flow unit's placement. A gas unit needs correct flueing and clearances from windows and openings, which a gasfitter sets to standard, related to gas fitting. Correct flueing keeps the whole unit safe. Poor placement is a hazard. It is worth getting right. Understanding that the flue and clearances matter for a gas continuous-flow unit's placement, since safety depends on it, is worth leaving to a licensed gasfitter.
Gas Versus Electric
Gas continuous-flow is the common choice for a whole home. A gas unit delivers high flow that can run several outlets at once, related to gas hot water system installation. This is gas. It delivers a high hot water flow. Whole home.
Gas needs a gas connection and a flue. A gas unit requires mains or bottled gas and correct flueing by a gasfitter, related to gas fitting. This is the gas need. It needs a mains or bottled gas supply. Flue required.
Electric continuous-flow suits a single outlet or small use. An electric instantaneous unit is limited in flow, good for one tap or a small flat, related to electric hot water installation. This is electric. It suits just a single hot outlet. Limited flow.
Electric units can need a heavy power supply. A whole-home electric instantaneous unit draws heavily and may need a dedicated circuit, related to electrical services. This is the power need. It draws heavily on the mains power. Dedicated circuit.
The right fuel depends on your gas access and demand. Where there is gas and high demand, gas suits, while electric suits small, gasless sites, related to hot water services. This is the choice. Gas suits high, whole-home hot water demand. Electric for small.
It is worth sizing the unit carefully to your peak flow, since an undersized one runs cool. A plumber counts the outlets you may run at once and picks a flow rate to match, related to instantaneous hot water system installation. Correct sizing gives endless hot water, while undersizing runs cool. It is worth getting right.
It is worth knowing that correct sizing is the key to happy continuous-flow use. An undersized unit runs cool when several taps run at once, so the flow rate must match your peak simultaneous demand, related to instantaneous hot water system installation. Correct sizing gives endless, hot water reliably. Undersizing runs it cool. It is worth getting right. Knowing that correct sizing is the key to happy continuous-flow use, since the flow must meet the peak, is worth taking time over.
It is worth understanding that a continuous-flow unit is rated in litres per minute of flow. The flow rate sets how many hot outlets it can run at once, so it is the key number to match to your home, related to instantaneous hot water system installation. A high flow rate runs more outlets. A low one runs fewer. It shapes the sizing. Understanding that a continuous-flow unit is rated in litres per minute of flow, since that sets its capacity, helps you pick the right size.
It is worth knowing that a higher flow-rate unit suits a larger household with several bathrooms. More people running showers and taps at once need a bigger unit to keep every outlet hot, related to instantaneous hot water system installation. A big household needs a bigger unit. A small one needs less. It shapes the size. Knowing that a higher flow-rate unit suits a larger household with several bathrooms, since demand rises with outlets, helps you pick the right unit.
It is worth remembering that a continuous-flow unit is used every day, so getting the sizing and install right pays off. A correctly sized, well-installed unit gives years of endless, reliable hot water, related to hot water services. A good install serves for many years. A poor one disappoints daily. It is worth doing well. Remembering that a continuous-flow unit is used every day, so getting the sizing and install right pays off, since it runs constantly, sums up the whole approach.
Sizing and Flow Rate
A continuous-flow unit is rated by its flow in litres per minute. The flow rate sets how many outlets it can run hot at the same time, related to instantaneous hot water system installation. This is the rating. It is rated in litres per minute flow. Sets the flow.
A larger household needs a higher flow-rate unit. More people and more simultaneous showers call for a bigger unit, related to hot water services. This is the size. It runs more hot outlets at once. Bigger unit.
An undersized unit will run cool if too many taps run at once. If demand exceeds the flow, the water cannot heat enough, so it goes lukewarm, related to hot water system installation. This is undersizing. Too many hot taps run at once. It runs cool.
The plumber sizes the unit to your peak simultaneous demand. They count the outlets you may run at once to pick the right flow rate, related to hot water system replacement. This is the sizing. They count the outlets run at once. Match the peak.
Getting the sizing right is the key to happy continuous-flow use. A correctly sized unit gives endless hot water without ever running cool, related to hot water services. This is the goal. It is sized to the busy peak correctly. Endless and hot.
It is worth being sure the trade will remove and dispose of the old tank or unit as part of the job. Clarifying who handles the removal and any rubbish avoids an unexpected extra task at the end of the works, related to hot water system replacement. A clear scope covers the disposal too. An unclear one leaves a mess. It is worth confirming. Being sure the trade will remove and dispose of the old tank or unit as part of the job, since it saves hassle, is a small but useful check.
What Is Involved
The demand is assessed and the unit sized. A plumber checks your outlets and household to pick the flow rate, related to instantaneous hot water system installation. This is the plan. The whole unit size is then set. Then priced.
In practice, the old system is removed or the site prepared. Any old tank or unit is taken out and the wall readied for the new one, related to hot water system replacement. This is the strip-out. The old system is now fully out. Space is cleared.
Licensed trades make the water and gas connections. A plumber and gasfitter run the water, gas, and flue, related to plumbing services. This is the connection. In practice, qualified licensed trades carry the work out. Done right.
The tempering valve is fitted for compliance. The tempering valve is set for safe, compliant delivery to the taps, related to hot water tempering valve installation. This is compliance. It delivers water safely at the fixtures. Rules met.
Finally the unit is commissioned. The unit is checked, set, and left ready to use, related to hot water system installation. This is commissioning. The unit is tested and finally set. Then running.
The Process
The home is visited and the demand assessed. A plumber assesses your outlets, household, and gas access, related to hot water services. This is the assessment. In practice, the busy peak demand is properly seen. Then sized.
The unit, fuel, and flow rate are agreed. You confirm gas or electric and the flow rate to suit your home, related to gas hot water system installation. This is the plan. In practice, the chosen options are then all set. Then booked.
The old system is removed and the wall prepared. Any old tank or unit is decommissioned and the mounting readied, related to hot water system replacement. This is the strip-out. In practice, the old unit is then cleared away. Wall prepared.
The unit, connections, and tempering are installed in order. The unit, the water, gas, and flue, and the tempering follow in sequence, related to hot water system installation. This is the install. Each trade takes its turn in order in most cases. Then set.
The commissioned unit is handed over to the home. It is tested, set, and handed back ready to use, related to hot water services. This is the handover. The whole unit is then fully finished. You are shown.
It is worth planning a like-for-like swap around a short hot water outage. Replacing an existing unit and reusing the connections is quick, so the hot water is only off for part of a day, related to hot water system replacement. A quick swap keeps the outage short. A bigger job takes longer. It is worth planning for. Because a like swap is done in part of a day, scheduling it for a convenient time is worth doing.
It is worth booking a periodic service for a continuous-flow unit to keep it running reliably for years. A simple check of the burner, controls, and valves keeps the unit efficient and catches wear before it becomes a fault, related to hot water system repairs. Regular servicing keeps it all running well. Neglect risks a breakdown. It is worth scheduling in. Booking a periodic service for a continuous-flow unit to keep it running reliably for years, since prevention beats breakdown, is a sensible habit. SafeWork NSW publishes duty-holder guidance covering this work.
How Long It Takes
A straightforward gas swap can take half a day to a day. Replacing a like unit reusing the gas and water is quicker work, related to hot water system replacement. This is a swap. It takes only about half a day. Quicker work.
A new install or relocation takes longer. Running new gas, water, or flue to a new spot spans more work, related to hot water system relocation. This is a new run. It involves quite a bit more work. Longer job.
Converting from a tank to continuous-flow adds work. Removing a tank and re-plumbing for a wall unit takes extra time, related to hot water system installation. This is the swap-over. The old tank comes right out first. More re-plumbing.
Gas and flue work add time and a gasfitter's visit. New gas or flueing needs a licensed gasfitter and adds to the job, related to gas fitting. This is the gas work. A licensed gasfitter is also needed here. Adds time.
In practice, a plumber gives a timeframe up front. A good plumber maps the swap or new run and the gas work, related to hot water services. This is the timeframe. Generally, a clear timeframe is given up front. Then planned.
It is worth comparing a like-for-like gas swap against a new install, since they differ greatly in cost. A swap reuses the existing gas and water and is quick, while a new gas run or relocation adds a gasfitter's work, related to hot water system relocation. A swap keeps the cost down, while a new run lifts it. It is worth comparing both.
It is worth understanding why the install type drives most of the cost of a continuous-flow system. A like-for-like gas swap reusing the existing gas and water is far simpler than a new gas run or a relocation, so the install type sets the scale, related to hot water system replacement. A simple swap keeps the cost right down. A new run lifts it. The install leads. Understanding why the install type drives most of the cost of a continuous-flow system, from a swap to a new run, helps you budget realistically.
It is worth being clear that a new gas run or flueing adds a gasfitter's work and cost. Where the existing gas cannot be reused, a licensed gasfitter must run new gas or flue, which lifts the price above a simple swap, related to gas fitting. Reusing the existing gas keeps it cheap. New gas costs more. It shapes the price. Being clear that a new gas run or flueing adds a gasfitter's work and cost, since it is extra work, helps you understand a higher quote.
It is worth thinking about the running costs over the life of a continuous-flow system, not just the price. For gas, continuous-flow is generally efficient, though for the lowest running cost overall a heat pump often wins, so it is worth comparing, related to heat pump hot water installation. An efficient choice saves you over years. A cheap fit can cost more. It is worth the long view. Thinking about the running costs over the life of a continuous-flow system, not just the price, since running cost adds up, is the sensible approach.
It is worth being aware that a relocation of the unit to a new spot adds re-plumbing and possibly new gas. Moving the unit means running water, gas, and flue to the new location, which is more work than a same-spot swap, related to hot water system relocation. A same-spot swap is the simplest option. A relocation adds work. It shapes the price. Being aware that a relocation of the unit to a new spot adds re-plumbing and possibly new gas, since services must be run, helps explain a higher quote.
It is worth remembering that a continuous-flow system is a long-term part of your home's plumbing. A correctly sized, well-installed, compliant unit gives years of endless, reliable hot water, which is why the sizing and quality matter, related to hot water services. A quality install serves reliably for years. A poor one causes daily grief. It is worth doing well. Remembering that a continuous-flow system is a long-term part of your home's plumbing, since it runs for years, sums up the whole approach.
It is worth asking whether an efficient heat pump might suit better if lowest running cost is your priority. While continuous-flow is efficient for gas, a heat pump often uses the least energy overall, so it is worth weighing at replacement, related to heat pump hot water installation. A heat pump can win on running cost. Continuous-flow wins on space and endless flow. It is worth comparing. Asking whether an efficient heat pump might suit better if lowest running cost is your priority, since goals differ, is worth doing before you decide.
What Affects the Cost
The install type is the biggest cost factor. Because a like-for-like swap is far simpler than a new gas run, the install type drives most of the cost. The install type drives most of the cost. A swap is cheaper. A new run costs more. That install type sets much of the price.
The unit and flow rate affect the cost. Because a higher flow-rate unit costs more than a small one, the unit shapes the total, related to instantaneous hot water system installation. A small unit is cheaper. A high-flow unit costs a good bit more. The unit affects the price.
The fuel affects the cost. Because gas and electric differ in unit and connection cost, the fuel shapes the total, related to electric hot water installation. Electric units are cheaper. Gas needs a good bit more work. The fuel affects the price.
The gas and flue work affect the cost. Because a new gas line or flueing adds a gasfitter's work, the works shape the total, related to gas fitting. Reusing gas is cheaper. New gas work costs a good bit more. The works affect the price.
The location and access affect the cost. Because relocating the unit or difficult access adds work, the conditions shape the total, related to hot water system relocation. A like spot is cheaper. A new location costs a good bit more. In practice, the conditions affect the price.
Continuous Flow Costs Across Sydney
Across Sydney, the cost of a continuous-flow system is set far more by the unit, the install type, and the gas work than by the postcode, though established suburbs with tight access or older gas can add to the labour. A larger unit needing a new gas run is where the cost climbs, while a like-for-like gas swap stays lower. A clear picture of your home and hot water use is the way to get an accurate Sydney estimate.
| Sydney Area | Typical Cost (installed) | Notes |
|---|---|---|
| Inner & Eastern Suburbs | $1,400-$3,700+ | Older homes |
| North Shore & Northern Beaches | $1,400-$3,700+ | Higher labour |
| Western Sydney | $1,200-$3,300 | Competitive |
| Hills & North West | $1,200-$3,500 | Newer stock |
| South & Sutherland | $1,200-$3,500 | Mixed ages |
The variation across Sydney reflects the install and the gas work more than the location. A new gas run pushes the cost up, while a like swap sits low. Existing gas and water reused keep it at the lower end. In practice, a clear picture keeps the estimate accurate wherever you are.
Continuous Flow Costs in Regional NSW
For regional properties, the practical points are the plumber's travel, the unit supply, and the gas available. Local trades handle the work, while a longer trip and bottled gas rather than mains can shape the cost. A clear picture lets a regional plumber give an accurate estimate in most cases.
| Regional Area | Typical Cost (installed) | Notes |
|---|---|---|
| Newcastle & Hunter | $1,200-$3,500 | Good supply |
| Central Coast | $1,200-$3,500 | Mixed ages |
| Wollongong & Illawarra | $1,200-$3,500 | Local trades |
| Regional cities | $1,200-$3,300 | Confirm gas |
| Rural & remote | $1,400-$3,800+ | Travel, LPG |
In regional NSW, the travel and gas supply are the main differences from the city. A longer trip and bottled LPG rather than mains gas can shape the cost and the unit. The trade work itself is much the same in most cases. Where there is no mains gas, an LPG or electric option may suit. Confirming the trades cover your area up front avoids surprises in most cases.
It is worth being clear that the licensed plumbing, gasfitting, and tempering are the non-negotiable parts of the job. The water and gas must be by licensed trades and the tempering must meet AS 3500, whatever the budget, related to plumbing services. In practice, licensed work keeps it legal and safe. In practice, compliant tempering protects users. Both stay. Being clear that the licensed plumbing, gasfitting, and tempering are the non-negotiable parts of the job, since safety depends on them, is the key point.
It is worth being aware that most gas continuous-flow units will not run during a power cut. Because they use electronic ignition and controls, they need a little mains power to fire, so a blackout stops the hot water, related to hot water services. Power keeps the electronic ignition working properly. A blackout stops it. It resumes on power. Being aware that most gas continuous-flow units will not run during a power cut, since they need electronic ignition, is worth knowing in outage-prone areas.
It is worth confirming the tempering valve is in the quote, since it is required for safe delivery. A tempering valve blends the hot water down to a safe temperature at the fixtures and is a compliance item, not an extra, related to hot water tempering valve installation. Tempering is required, not just an option. A quote should include it. It is worth checking clearly. Confirming the tempering valve is in the quote, since it is required for safe delivery, keeps the comparison honest and complete.
It is worth being clear on exactly what the quote includes before you compare prices between trades. Because a continuous-flow quote can range from a simple swap to a new gas run or conversion, knowing what each covers is essential, related to hot water system installation. In practice, a detailed quote lists every element clearly. A vague one hides the gaps. It is worth pinning down. Being clear on exactly what the quote includes before you compare prices between trades, since scope varies so much, keeps the comparison honest.
It is worth remembering that a continuous-flow install is a job for licensed trades, not a DIY task. The gas, the flueing, the water, and the tempering all need skill and the right licences to be safe and legal, related to plumbing services. Licensed trades deliver a safe, compliant install. DIY gas work is dangerous. In practice, it is worth using professionals. Remembering that a continuous-flow install is a job for licensed trades, not a DIY task, since gas is involved, protects your home.
It is worth being clear that a professional continuous-flow install leaves you with certification for the gas and plumbing. A licensed trade provides the required paperwork for the gas and water work, which matters for compliance and any future sale, related to plumbing services. Proper certification protects you down the track. Missing paperwork causes trouble later. It is worth keeping records. Being clear that a professional continuous-flow install leaves you with certification for the gas and plumbing, since compliance matters, is a sensible final check.
What to Look Out For
The first thing to watch is that the unit is sized to your real peak flow. Because an undersized unit runs cool when several taps run, sizing to your busiest moment is essential. This is the key point. In practice, always size it to the busy peak. Never run cool.
Confirm the water, gas, and flue are by licensed trades. In practice, because this work is regulated and safety-critical, always check the licences, related to plumbing services. This is licensing. In practice, it is strictly licensed plumbing work only. Confirm it.
Be clear that the tempering valve is included. Because it is required for safe delivery, it should be in the quote, related to hot water tempering valve installation. This is compliance. In practice, the tempering must always be clearly included. Rules met.
Watch whether a new gas run or flue is needed, as it adds cost. Because a like swap and a new gas run differ greatly, know which you need, related to gas fitting. This is the gas. It is a swap or a new run. Know the cost.
Be wary of a quote that undersizes the unit or cuts the licensed work to hit a price. A continuous-flow system depends on correct sizing, licensed plumbing and gasfitting, and compliant tempering, and a cheap quote may fit a too-small unit or skip the safe work. An undersized unit that runs cool, or unlicensed gas work, can leave you with poor hot water or a real safety risk that costs far more to put right. Ask exactly what is included and how the unit was sized before comparing prices. A sound continuous-flow install is built on the sizing, the licensing, and the tempering. These matter far more than the lowest headline price in most cases.
It is worth gathering a few quotes so you can compare the sizing, the unit, and the price together. Describing your home and its hot water use once on The Quote Yard brings responses from several trades, so you can weigh their sizing and prices side by side, related to hot water services. A single quote gives no yardstick at all. A few let you compare well. It is worth getting several. Gathering a few quotes so you can compare the sizing, the unit, and the price together, since sizing varies between quotes, is the sensible way to choose.
It is worth asking about warranty and servicing on a continuous-flow unit when you choose a trade. Because a unit lasts many years, a solid warranty and any servicing give reassurance and protect your investment, related to hot water system repairs. In practice, a good warranty backs the whole job. In practice, its absence is worth questioning. It is worth confirming. Asking about warranty and servicing on a continuous-flow unit when you choose a trade, since it lasts for years, is a sensible step.
It is worth remembering that the trades on The Quote Yard include licensed plumbers and gasfitters. Skilled hot water trades across NSW size and install continuous-flow units regularly, so a clear brief connects you with the right ones, related to hot water services. A clear brief reaches the right trades in most cases. A vague one does not. Detail really helps here. Remembering that the trades on The Quote Yard include licensed plumbers and gasfitters, since matching matters, makes for a smoother project.
It is worth describing your home and its hot water use clearly when you ask for a continuous-flow quote. Noting your household size, the number of bathrooms and outlets, what system you have now, and whether you have mains gas helps a trade size and quote accurately, related to hot water services. In practice, a detailed enquiry earns a real, sized estimate. In practice, a vague one gets a rough guess. It is worth being thorough. Describing your home and its hot water use clearly when you ask for a continuous-flow quote, since the trade can then size the unit, is the simplest way to compare fairly.
It is worth checking the warranty terms on both the unit and the workmanship before you commit. A good continuous-flow unit carries a solid manufacturer warranty, and a good trade backs its installation, related to hot water system repairs. A strong warranty stands behind the whole install. A weak one is worth questioning. It is worth reading it. Checking the warranty terms on both the unit and the workmanship before you commit, since it lasts for years, is a sensible step. A tradesperson's standing can be checked with NSW Fair Trading.
What to Look for in a Quote in NSW
A good continuous-flow quote is clear about the sizing, the unit, the gas work, and the tempering. It should set out the flow rate and how it was sized, the unit and fuel, the licensed plumbing and gasfitting, any new gas or flue work, and the tempering valve, so you can compare quotes and avoid surprises. With that detail you know the unit will meet your demand and that the safe work is included. A vague price that hides the sizing or the gas work is a red flag. The sizing, the unit, the gas work, and the tempering are what to confirm.
Confirm the flow rate the unit is sized to. Because the flow must meet your peak, a good trade explains the sizing, related to instantaneous hot water system installation. Asking is reasonable. In practice, a good trade readily shows the working. They size it properly.
Compare on flow, inclusions, and quality, not just the headline price. A quote that meets your flow, includes the tempering, and uses a reliable unit is worth more than the cheapest, much as with any hot water or plumbing work. Weigh the sizing, the unit, and the gas work. Describing the job once on The Quote Yard brings responses from several trades, so the final choice can rest on flow and quality as much as price. Looking at flow, inclusions, and quality, not just the headline, is what keeps the hot water endless.
Ask about warranty and servicing on the unit. Because a continuous-flow unit lasts many years, a good trade covers the warranty and any servicing, related to hot water system repairs. This gives peace of mind. In practice, raising it early is a sensible move. Knowing it is covered is reassuring. Energy NSW publishes guidance on efficiency programmes.
Continuous Flow Hot Water Across NSW
We connect homeowners with licensed hot water and plumbing trades across NSW, covering the assessment of your hot water demand, the sizing of the unit to your peak flow, the removal of any old system, the licensed plumbing and gasfitting connections, the flueing, the fitting of the tempering valve for safe delivery, and the commissioning of the unit, so you enjoy endless, on-demand hot water, for homes across Greater Sydney, Newcastle, Wollongong, the Central Coast, the Hunter, and regional NSW.
▶ Sydney Inner City 18 areas
▶ Greater Sydney 25 areas
Western Sydney
South Western Sydney
Northern Sydney
The Hills District
Inner West
St George
▶ Sydney Coastal 23 areas
Northern Beaches
Eastern Suburbs
Harbour Suburbs
Sutherland Shire
▶ Hunter & Central Coast 19 areas
Central Coast
Hunter Valley
Port Stephens
▶ Illawarra & South Coast 18 areas
Illawarra
Shoalhaven
Sapphire Coast
▶ North Coast 19 areas
Mid North Coast
Coffs Coast
Northern Rivers
▶ Blue Mountains & Highlands 17 areas
Blue Mountains
Southern Highlands
▶ Regional NSW 21 areas
Central West
Riverina
New England
Far West
Continuous Flow Hot Water FAQs - NSW 2026
How much does a continuous-flow hot water system cost in NSW?
A continuous-flow hot water system in NSW typically costs around $1,200 to $3,500 supplied and installed, depending mainly on the unit and flow rate, the fuel, the install type, and any gas or flue work. A straightforward like-for-like gas swap, reusing the existing gas and water connections, commonly costs around $1,200 to $2,800. A larger unit, or one needing a new gas line or flueing, or a relocation, runs about $2,500 to $3,500 or beyond. The unit alone runs roughly $900 to $2,200 depending on the flow rate, an electric continuous-flow unit around $1,000 to $2,500, a required tempering valve about $250 to $600, and any gas or flue work around $300 to $1,200. The biggest cost driver is the install type, because a simple swap is far cheaper than a new gas run. Because the licensed plumbing, gasfitting, and tempering cannot be skimped, always get a written quote that sets out the flow rate and separates the safe work from the unit. On The Quote Yard you can compare quotes from licensed hot water trades across NSW.
What is a continuous-flow (instantaneous) system?
A continuous-flow system, also called instantaneous, on-demand, or tankless, is a hot water system that heats water only as you use it, rather than storing it in a tank. When you turn on a hot tap, water flows through the unit and past a gas burner or electric element that heats it instantly, so hot water is produced continuously for as long as the tap is running. The key advantages are that it never runs out, because there is no tank to empty, so you can shower for as long as you like; it is compact and wall-mounted, freeing up the space a tank would take; and it wastes no standing heat keeping stored water hot around the clock, which can make it efficient. Most continuous-flow systems in Australian homes are gas, because gas delivers the high flow needed to run a whole home, though electric instantaneous units exist for single outlets or small uses. The main thing to get right is sizing the unit's flow rate to your peak simultaneous demand. On The Quote Yard you can find trades who install continuous-flow systems across NSW.
Does a continuous-flow system really never run out?
A correctly sized continuous-flow system effectively never runs out of hot water, which is one of its main attractions, but there is an important qualification: it must be sized to your peak flow. Because it heats water as it passes through, it can supply hot water indefinitely, so unlike a storage tank it will not empty part way through a long shower or a run of showers. However, a continuous-flow unit has a maximum flow rate, measured in litres per minute, which is the amount of hot water it can heat at once. If you try to run more outlets simultaneously than the unit is rated for, such as two showers and a kitchen tap all at once on a small unit, the water may run cooler because the unit cannot heat that much flow to temperature. This is why sizing the unit to your peak simultaneous demand is so important. Sized correctly, a continuous-flow system gives endless hot water for your household's normal peak use. On The Quote Yard you can find trades who size and install them across NSW.
Should I choose gas or electric continuous-flow?
For a whole home, gas continuous-flow is usually the practical choice, while electric continuous-flow suits smaller or single-outlet uses. Gas units deliver a high flow rate, enough to run several outlets at once, which is what most households need, and they are the standard for whole-home instantaneous hot water where mains or bottled gas is available. They do require a gas connection and correct flueing by a licensed gasfitter. Electric continuous-flow units, by contrast, are limited in flow because heating a high flow of water electrically draws a great deal of power, so they are best for a single outlet, a small flat, or a specific point of use rather than a whole busy home. A whole-home electric instantaneous unit can require a heavy, dedicated electrical supply that many homes do not have. So the choice largely comes down to whether you have gas and how much simultaneous hot water you need. A trade can advise based on your gas access and demand. On The Quote Yard you can find trades who install both across NSW.
Can I switch from a storage tank to continuous-flow?
Yes, switching from a storage tank to a continuous-flow system is a common upgrade, though it involves a little more work than a like-for-like swap. The process typically involves removing the old storage tank, preparing the wall or location for the compact continuous-flow unit, re-plumbing the water connections to suit, and, for a gas unit, ensuring there is an adequate gas supply and correct flueing, which a gasfitter handles. Because a continuous-flow unit often has different connection points and gas requirements than an old tank, the changeover is more involved than simply replacing a tank with another tank, and the cost reflects this. The benefits of switching are endless hot water, the space freed up by removing the tank, and potentially better efficiency. Whether it is straightforward depends on your existing setup, particularly the gas supply, which a trade can assess. Many households find the switch worthwhile for the endless supply and space saving. On The Quote Yard you can find trades who convert tanks to continuous-flow across NSW.
How long does a continuous-flow install take?
The time depends on whether it is a straightforward swap or a more involved new install or conversion. A like-for-like gas continuous-flow swap, replacing an existing unit and reusing the gas and water connections, can often be done in half a day to a day. A conversion from a storage tank to continuous-flow takes longer, because the old tank must be removed and the water re-plumbed for the wall unit, and the gas supply and flueing checked. A relocation to a new position, or an install requiring a new gas line or flueing, is more involved again and can take a day or more, as running new gas or flue is additional work requiring a licensed gasfitter. The main factors that add time are new gas or flue work, re-plumbing for a different unit type, and relocating the system. A good trade will assess what your job involves and give you a clear timeframe up front, so you know how long the hot water will be off. On The Quote Yard you can find trades across NSW.
Is continuous-flow more efficient than a storage tank?
Continuous-flow systems can be more efficient than storage systems in one important respect: they have no standing heat loss. A storage tank keeps a large volume of water hot around the clock, and some of that heat is continually lost to the surroundings even when no hot water is being used, which wastes energy. A continuous-flow unit only heats water when you actually use it, so it avoids this standing loss entirely, which is one reason it is often described as efficient. Whether it works out cheaper to run overall depends on your usage pattern, the fuel, and the alternative you are comparing it with. For gas, continuous-flow is generally efficient for typical households. It is worth noting that for the lowest running costs overall, a heat-pump hot water system is often the most efficient option, using far less energy than either gas or conventional electric, though it is a storage type. The best choice depends on your priorities, and a trade can help weigh efficiency, capacity, and cost. On The Quote Yard you can find trades who advise across NSW.
How do I get a continuous-flow quote?
The best way to get an accurate quote is to describe your home and its hot water use, because the cost is driven by the unit and flow rate, the fuel, the install type, and any gas or flue work. It helps to note the size of your household, how many bathrooms and outlets you have and might run at once, what system you have now, whether you have mains gas, bottled gas, or no gas, and whether the new unit would go in the same spot or a new location. Mentioning access and any known issues is also useful, since these affect the work. Because the sizing, the licensed plumbing and gasfitting, and the tempering must all be right, expect a trade to want to assess your demand and setup, and a good quote should set out the flow rate and separate the safe work from the unit. This lets you compare quotes fairly and be sure the unit will meet your demand. On The Quote Yard you can describe your job once and get quotes from several licensed hot water and plumbing trades across NSW.
Does a continuous-flow system need a tempering valve?
Yes. In NSW, hot water delivered to bathroom and personal-hygiene fixtures must be at a safe temperature to prevent scalding, in line with AS 3500, and this applies to continuous-flow systems just as it does to storage systems. A tempering valve, or thermostatic mixing valve, is fitted to blend the hot water down to a safe delivery temperature at the relevant outlets. Many continuous-flow units allow the outlet temperature to be set, and some models are designed to deliver at a preset safe temperature, but a tempering valve is still commonly required and installed to ensure compliant, safe delivery, particularly to bathrooms. This is a compliance and safety requirement, not an optional extra, and a licensed plumber will ensure the correct arrangement is in place. When comparing quotes, it is worth checking that the tempering valve is included, as leaving it out would make a quote look cheaper while missing a required item. On The Quote Yard you can find licensed trades who install continuous-flow systems compliantly across NSW.
Do continuous-flow systems work in a power outage?
Most gas continuous-flow systems will not produce hot water during a power outage, which surprises some people given they run on gas. This is because modern gas continuous-flow units use electronic ignition and controls that need a small amount of mains electricity to operate, rather than a standing pilot light, so when the power is out the unit cannot fire. The gas itself is still available, but the electronics that control and ignite the burner are not powered. This is generally only an issue during a blackout, and normal mains power is restored the unit works again immediately with no need to relight anything. For most households this is a minor consideration, but if you are in an area prone to extended outages or have a specific need for hot water during blackouts, it is worth discussing with your trade, as there can be options. Electric continuous-flow units, of course, also need power. A trade can advise on your situation. On The Quote Yard you can find trades across NSW.
Hot Water Services - NSW
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Reviewed by The Quote Yard Editorial Team
How The Quote Yard Works
We connect you with independent local tradies and service providers, we don't perform any trade work ourselves. Tradies provide their own quotes directly to you. Always confirm licensing, insurance, and scope of work before engaging any provider.
All NSW tradies are required to hold appropriate licences. Verify at NSW Fair Trading.
These are indicative 2026 NSW estimates only. The unit size and flow rate, the fuel, the gas and flue work, the tempering, and the installation all drive the final price; a straightforward gas swap costs far less than a larger unit needing a new gas run.