Gas and Continuous Flow Hot Water Sunshine Coast

A continuous flow unit is rated by how many litres per minute it can raise by a given temperature. That rating assumes an incoming water temperature, and incoming water is cooler in winter, so the same unit delivers less on a cold morning than on a warm afternoon.

The practical sizing question is simultaneous outlets. One shower is straightforward. Two showers at once, or a shower plus the kitchen sink, is where an undersized unit shows itself.

The symptom is specific and worth recognising: not cold water, but the temperature sagging at one outlet when another opens. If that describes your existing system, it is undersized rather than broken.

Temperature controllers are worth asking about, particularly in a household with young children, since they let you set delivery temperature at the outlets rather than relying on mixing at the tap.

The unit needs a certain amount of water moving before it will fire. Below that threshold you get cold water, because the burner has not engaged. This catches people with very low-flow fixtures, or with a tap opened only slightly. It is a design characteristic rather than a fault, but it is the sort of thing that generates a service call because nobody mentioned it at installation.

Water sitting in the pipe between the unit and the tap is at room temperature. When you open the tap, that has to come through before the heated water arrives, so there is a delay proportional to the length of the run. On a compact house it is barely noticeable. On a long run to a distant bathroom it is genuinely annoying, and it is one reason unit placement is worth thinking about rather than defaulting to where the old system was.

You can also get a brief cold slug mid-use if the unit cycles off and on, typically when flow drops near the activation threshold.

On the Sunshine Coast, gas almost always means LPG. It arrives in bottles, and that brings practicalities: cost per unit is generally higher than piped gas, you have to manage refills or exchanges, and running out mid-shower is a real event rather than a theoretical one. With heavy use a continuous flow unit can go through bottles quickly, which is worth pricing before committing.

Natural gas is piped and metered, and where it is connected it is generally the cheaper of the two per unit of energy and the more convenient, because it does not run out. Very few properties here have it, and running a new connection rarely pays for itself on hot water alone.

Appliances are configured for one or the other. A unit set up for natural gas will not simply run on LPG, and conversion is not always possible or economic.

Gas storage keeps a tank at temperature, ready to use, and reheats after it is drawn down. It delivers at full flow and will not falter when a second tap opens. It can run out, and it loses heat from the stored water between uses. On the coast it is the smaller share of the gas work, but it is still the right answer on some properties.

Continuous flow heats water only while it is being drawn. It does not run out and it has no standby loss, but it is limited by flow rate: how much water it can raise to temperature per minute. Open enough outlets at once and the temperature drops.

Neither is better in the abstract. The question is whether your household's constraint is total volume or simultaneous demand.

The most common surprise on a gas hot water job is that the existing supply cannot feed the new unit. A larger continuous flow appliance demands considerably more gas while running than a small storage heater, and the regulator, the line and, on mains, the meter were sized for what was there before.

Gas appliances also need ventilation and clearances, and those get compromised over the years by fences, decking, storage and plants appearing around what used to be open space.

Electric continuous flow exists, but it draws a substantial current for the heating it does, and the switchboard and supply have to carry it, which limits where it is practical.

All of this is assessed before quoting, because it changes the job substantially and nobody wants to discover it on installation day.

Continuous flow units are controller-driven, so faults usually announce themselves as an error code. Those codes are manufacturer-specific and worth sending us before a visit: some indicate a reset, others a part. Ignition components, flow sensors and heat exchangers are the usual suspects, and scale can build up in the heat exchanger over time depending on water quality.

On storage units, pilot and ignition problems are usually a thermocouple or debris around the burner, and a gas control valve failure typically presents as a system that will not fire at all.

Because a continuous flow unit has no tank, a fault takes your hot water away immediately rather than after a reservoir empties, which is worth knowing when deciding how urgently to deal with an intermittent problem.

As with any gas appliance, if you can smell gas near it, leave it alone and call from somewhere else.

Continuous flow wins where space is tight, since there is no cylinder. It wins where demand is spread rather than concentrated, where nobody wants to think about running out, and where standby loss from a tank is an irritation. Against a heat pump, gas has a lower upfront cost in most cases and no positioning or noise constraint. Against solar, it is unaffected by roof orientation and weather, which is a genuine advantage on a shaded or poorly oriented property.

It is less convincing where several outlets genuinely run at once and the flow rate would have to be large, where bottle costs would mount with heavy use, or where the household would rather have a reservoir than a rate. And it burns fuel: a heat pump moving heat rather than generating it uses substantially less energy per unit of hot water.

Which of those trade-offs matters is a decision about your property and your priorities, and the comparison page lays them out side by side.