Heat pump hot water on the North Shore used to be a curiosity. Now it is one of the first questions asked when a gas unit finally gives up. From the outside the swap looks simple. One box comes off the wall and another takes its place.
The two systems work nothing alike. A heat pump sits somewhere else, makes a noise gas never made and refills a tank on its own schedule. None of that is a reason to avoid one. It is a reason to know what shifts before the old unit leaves the wall.
Is heat pump hot water the right swap for a North Shore gas system?
For most homes, yes, as long as there is a sensible outdoor spot for it. Blocks around Pymble, Killara and Wahroonga usually have the side access and garden setback a heat pump wants. Narrower lots closer to Chatswood are harder. The unit needs clear air around it, and a neighbour’s bedroom window changes the maths.
How does a heat pump actually heat the water?
It moves heat rather than making it. A fan draws in outside air, a refrigerant circuit lifts that warmth to a useful temperature and the heat goes into a storage tank. Running costs usually drop, because the compressor shifts existing heat instead of burning fuel to create it. The trade-off is that the heat arrives slowly.
How long does a heat pump take to recover?
Several hours, against a gas continuous flow unit that never runs out at all. That one difference causes most of the early complaints. A household used to endless gas hot water has to think about tank size and timing again.
Getting the tank size right matters more than it did before. Too small, and back-to-back showers will find the bottom of it. The old unit gives no clue either, because a gas instantaneous system has no tank and no daily limit to measure. Sweeney’s Plumbing sizes the tank to the household instead.
What happens to the gas connection?
It stays live if anything else on the property runs on gas. A cooktop, a heater or a pool unit all keep the meter in service. Where the water heater was the only gas appliance, the point needs capping off properly. Capping it counts as licensed gas work, not a job to leave half done.
Some owners keep the gas unit as a backup instead. On a large household that can make sense, though it does mean maintaining two systems. If the existing unit is near the end of its life anyway, whether to repair or replace an ageing one is the first thing to settle.
What needs sorting before the unit goes in?
Four things. Where it sits, how loud it is at the boundary, the pipework around it and who signs off the job. Each one has a rule behind it.
Where is a heat pump allowed to sit on the block?
Almost anywhere outside, as long as it meets the conditions for exempt development. That means no council application at all. NSW Planning sets those conditions out in the rules for exempt and complying development. Solar hot water is excluded from the same clause, so a solar swap follows a different path.
What noise limits apply at the boundary?
A heat pump must run at no more than 5 dB(A) above the background noise level, measured at the property boundary. That limit applies between 8 am and 10 pm on Saturdays, Sundays and public holidays, and between 7 am and 10 pm on other days. Outside those hours, people in habitable rooms next door must not be able to hear it at all.
That rules out a few spots. Under a neighbour’s bedroom window is the obvious one. Setting the timer to heat in the early afternoon keeps the unit well inside the quiet hours.
What changes in a heritage conservation area?
A good deal of Ku-ring-gai sits inside one. Where a system goes in externally on a heritage item or in a conservation area, the same rules require it to be in the rear yard and not on a roof. On plenty of Gordon and Warrawee properties that single condition decides the location first.
What plumbing work does the changeover involve?
More than reconnecting two pipes. Building Commission NSW lists four faults it keeps finding, in its advisory note on heat pump installations.
The temperature and pressure relief drain has to finish where discharging hot water will not scald anyone, between 75 mm and 300 mm above a gully or gravel pit. The plumber tests incoming pressure and fits a pressure limiting valve where the reading calls for one. That is the fitting near the meter that holds mains pressure down, and without it the relief valve can fail. Pipes and relief lines need insulation to the R-value set for the climate zone. The tank has to sit on a level, stable and impervious base.
A tempering valve belongs in the run too, because it blends stored water down before it reaches a tap. Building Commission NSW sets out the requirements for temperature control devices separately.
Who should handle a heat pump hot water North Shore changeover?
A licensed plumber, with a gas fitter for the capping work and an electrician for the circuit. Sweeney’s Plumbing holds the plumbing and gas trades in house across the suburbs north of the harbour, which keeps the visits down.
There is money on the table as well. NSW runs a hot water upgrade incentive for households, so the current terms are worth reading before anyone settles on a model.
Still weighing a heat pump against another gas storage or continuous flow unit? The honest answer turns on the spot available, the size of the household and what else runs on gas. Sweeney’s Plumbing will look at all three on site, with a free estimate before anything goes on order. Start on the contact page or ring the office on 1800 219 682.
