Hot Water Heat Pump Buyer’s Guide 2026 + Sizing Calculator: Brands, Noise, Rebates, Running on Solar

Checked and updated by our licensed electricians: October 2026

Hot water is usually the second-biggest energy user in a Northern Rivers home after air conditioning, and a heat pump does the job with about a quarter to a third of the electricity of the old cylinder. This guide covers how they work, the brands sold in Australia with their noise, refrigerant, warranty and climate ratings, how to size one, how to run it on your own solar, the coastal cautions, the federal STCs and the NSW discount as they stand in October 2026, and what the installation needs. The calculator at the top gives you a tank size and the daily energy for your household before you talk to anyone. Written by local electricians; we are not a hot water retailer and the brands are compared on their published figures.

On this page: The calculator: tank size, energy and solar fit · How a heat pump heats water · Honest pros and cons · Brands sold in Australia: 23 models compared · CO2, R290, R134a and R513a · Sizing by household · Running it on solar (and with a battery) · Noise and placement · Coastal and salt air · STCs and the NSW discount in 2026 · What the installation needs · How we fit in, and our plumbing partner · Questions we get asked

Heat pump sizing calculator

Four taps: household size, what heats your water now, your solar and whether you have a battery. The result shows on screen straight away; sending it to your phone is optional.

How a heat pump heats water

A hot water heat pump is a fridge running backwards. A fan pulls outside air across a cold coil, the refrigerant inside soaks up heat from that air, a compressor squeezes it so it gets hot, and that heat passes into the water in the tank. Because it moves heat rather than making it, a good unit puts three to five units of heat into the water for every unit of electricity it uses; that ratio is the COP. An electric element gives you one for one. The COP climbs with air temperature (roughly 3 to 4 in 10 degree air, about 5 in 25 degree air), which is why heating at midday in the Northern Rivers is such a good fit.

All-in-one or split. An all-in-one (integrated) unit has the heat pump sitting on top of the tank, one box, plugged into a 10 or 15 A circuit, and is the most common type (iStore, Rheem, Solahart, Rinnai, Haier and most others). A split system (Sanden, Reclaim, Thermann X) has a separate compressor unit joined to the tank by pipes, is quieter, can heat hotter water and can be sited away from the tank, and costs more.

Honest pros and cons

For: a quarter to a third of the electricity of an electric tank; a running draw of only about 0.5 to 1 kW, so a normal solar system carries it easily; quiet enough to live with when sited sensibly; STCs plus the NSW discount take a useful slice off the price; lower emissions; no gas bill if it was your last gas appliance.

Against: costs more up front than an electric tank; needs outdoor space and clear airflow; makes some noise while heating; more moving parts than an element; and it heats slowly (about 1 litre a minute for mid-range units and 2 for premium ones, against 3 for an electric element and 4 for gas), so you need a bigger tank than you might expect and, if you run it dry, up to an hour to recover. Very cheap units (under about $2,000) tend to be noisy, inefficient and short-lived; SolarQuotes and CHOICE both say so and so does our experience of what we see on switchboards.

Brands sold in Australia: 23 models compared

Published figures only, from the makers’ data sheets, SolarQuotes’ heat pump comparison (updated October 2026) and CHOICE. Where a brand sells one design in several tank sizes it is one row. Prices are not shown: they move month to month and depend on the installer, the rebates and the site, so ask for quotes. “Not published” means we could not find a checked figure. Checked october 2026.

Noise is the maker’s laboratory figure at 1 m; installed noise is a little higher. COP is the maker’s rated figure at its own test conditions (CHOICE’s seasonal figures are often different). Warranty figures are the headline tank and heat pump years; most makers give shorter cover on parts and labour, so read the document. Quantum’s 35 degree upper air limit is the one climate rating that counts against a unit in our area. Stiebel Eltron WWK 222/302 are discontinued but still in stock at some retailers.

CO2, R290, R134a and R513a

• CO2 (R744): global warming potential of 1, makes very hot water, keeps working well in cold air, runs at high pressure so the hardware costs more. The premium split-system choice: Sanden, Reclaim, Thermann X.
• R290 (propane): GWP 3, now the standard in mid-range all-in-one units (iStore, Rheem AmbiPower, Solahart Atmos Eco, Rinnai, Haier, Evoheat, Emerald, Quantum, Apricus, Hydrotherm, Chromagen Midea, Neopower). Flammable, so it is used in a small sealed charge (about 0.35 to 0.5 kg) outdoors. A Macquarie University study found it about 10 per cent more efficient than R134a in air above 20 degrees.
• R134a: the older HFC (GWP about 1,430), being phased out; still in older Stiebel WWK units and some older Rheem and Solahart stock.
• R513a: a lower-GWP HFC blend Rheem and Solahart moved to in 2024-25 as a halfway step (Ambiheat HDc270, Atmos Frost).

For our climate, CO2’s cold-weather edge is not needed. Its real benefits here are quiet running (about 37 dB), hot delivery temperature and long warranties. An R290 all-in-one is the value pick for most homes.

Sizing by household

Work on about 50 litres of hot water per person per day and about a day and a half of storage, because heat pumps reheat slowly. SolarQuotes and the Victorian government guides land on the same numbers:

Go up a size for long showers, a spa bath, teenagers or regular guests; 260 to 270 L is the most common size sold, and with a heat pump bigger is safer than smaller. Reclaim’s warranty treats a unit running more than 18 hours a day as undersized. A full reheat takes three and a half to five hours for most all-in-one units.

Running it on solar (and with a battery)

This is where a heat pump earns its keep. It draws about 0.5 to 1 kW while heating, against 1.8 to 4.8 kW for an electric element, so even a 6.6 kW system (about 25 kWh on an average Northern Rivers day, 15 to 20 kWh of it between 10am and 4pm) runs it with plenty left over. Three things make it work:

1. A timer. Pick a unit with a built-in timer (so the power is not cut mid-cycle) or have the electrician fit one on the circuit. Start about 10 or 11am and let it run three to six hours; one window is usually enough in summer, add a second block in winter or for big households, and keep to the maker’s minimum run time. Some units (Emerald, Haier) follow surplus solar automatically.
2. Off the old off-peak circuit. An old electric tank on Essential Energy’s Controlled Load 1 only gets power at night, which is useless for solar. The electrician moves the heat pump to the normal (continuous) supply on a dedicated circuit, or your retailer switches it to Controlled Load 2, which Essential Energy allows seven days a week outside the morning and evening peaks.
3. A home battery for the rest. With the hot water moved into the solar window, the battery covers the evening: lights, cooking, air conditioning. A Sigenergy or GoodWe system can also switch a heat pump circuit on when the panels are exporting. See the home battery buyer’s guide and the 60-second battery quiz.

Legionella: the tank must store water at 60 degrees or above and a tempering valve keeps tap water under 50; most units run a periodic sterilisation cycle themselves. Related reading: time-of-use tariffs and feed-in tariffs with solar and a battery, how big a solar system do I need.

Noise and placement

Published levels for decent units are 37 to 50 dB(A) at 1 m: splits at about 37, most all-in-ones 43 to 48, the loudest mainstream units 50. Installed noise is higher than the lab figure because walls reflect sound, and the “quiet as a fridge” line is optimistic for the louder units. Complaints are uncommon when the unit is sited well.

Where to put it. Outdoors, on a level slab or paver covering the whole base, with the maker’s clearances (Reclaim 100 mm each side, iStore 300 mm from walls), away from corners and alcoves that bounce sound, clear of shrubs and trees that choke airflow, and away from your own and your neighbour’s bedroom windows and outdoor eating areas. A garage works only with good ventilation and drainage. Under the NSW noise regulation a heat pump water heater must not be heard inside a neighbour’s habitable room before 7am or after 10pm on weekdays, or before 8am or after 10pm at weekends and public holidays; a daytime timer takes care of that and suits solar anyway. (The NSW EPA consulted on a replacement regulation in 2026; check the current version before you rely on the hours.)

Coastal and salt air

Unlike our battery makers, none of the heat pump makers we checked publishes a distance-from-the-coast rule. What they do say: Reclaim’s warranty excludes damage from a “corrosive atmosphere” and from water outside its chemistry table; Sanden sells 316 marine-grade stainless tanks and its manual says not to install where the unit is exposed to sea water or spray; Stiebel Eltron and Solahart exclude corrosive water chemistry but say nothing about salt air; iStore publishes no coastal clause. For a home within sight of the surf (Byron Bay, Lennox Head, Kingscliff, Pottsville, Brunswick Heads, Evans Head), the honest approach is a stainless-tank split or a unit with a coated or separate exchanger, sited on the sheltered side of the house, hosed down now and then, with the maker’s position confirmed in writing before you buy. Our solar and batteries near the coast guide covers the same question for the rest of the system.

STCs and the NSW discount in 2026

Federal STCs. Heat pump water heaters up to 425 L on the Clean Energy Regulator’s register earn small-scale technology certificates, which the installer claims and takes off the price. The register lists each model’s 10-year figure by climate zone; the real number is that figure times the deeming period, which is 5 years for installs in 2026, 4 in 2027, 3 in 2028, 2 in 2029 and 1 in 2030, stepping down every 1 January by install date. All Northern Rivers postcodes (2470 to 2490) are heat pump zone 3. Worked example: a 270 L iStore is listed at 31 certificates over ten years in zone 3, so a 2026 install earns 15 and a 2027 install 12; SolarQuotes’ table shows 15 to 17 for the mainstream 2026 units. The dollar value moves with the certificate price (a few hundred dollars to upwards of $600).

NSW Energy Savings Scheme hot water upgrade. Live with no closing date (official page updated February 2026). Replacing an existing electric heater with an eligible heat pump earns an upfront discount on the installer’s quote, indicatively up to about $640; replacing gas, up to about $330. The amount depends on the model’s rated savings, the installer and the certificate price. Conditions: the installer works with an IPART-accredited certificate provider, you sign a nomination form before the work starts (no retrospective claims) and a declaration with photos afterwards, you pay a minimum co-payment, and since 1 December 2025 the unit must carry at least a five-year defects warranty on the unit, tank and maker-supplied parts. Installing a heat pump where there was no hot water system earns nothing. The separate Peak Demand Reduction Scheme payment for home heat pumps was suspended in December 2024 and removed in July 2026, so the “free heat pump” offers of 2024 are gone.

Not covered: the federal Cheaper Home Batteries rebate applies to batteries only (see who qualifies). The NSW Home Energy Saver 0% loan lists heat pumps as compatible but says lenders may not finance every product; as part of a solar and battery package it is straightforward. No Northern Rivers council runs a heat pump rebate in 2026.

What the installation needs

• Two licensed trades. A plumber for the water side (tank, valves, tempering valve, drains) to AS/NZS 3500.4 and the maker’s manual; an electrician for the dedicated circuit and isolator. Skipping either puts the warranty and the NSW incentive at risk.
• Circuit. Most all-in-one units run on a 10 A circuit (iStore 270: under 1 kW typical, 1.5 kW maximum); units with a 2.4 kW element need 15 A (Solahart Atmos Frost, Rinnai Enviroflo); CO2 splits draw up to about 2.5 kW and are hardwired. A dedicated hardwired circuit with a lockable isolator beats sharing a power-point circuit that can trip and leave you cold.
• Tariff. Off Controlled Load 1 and onto the continuous supply with a timer (for solar), or Controlled Load 2 (for grid heating in the daytime windows).
• Drains. The relief valve discharge and a condensate line to a proper drain with an air gap, never onto the ground near electrical gear; the first 500 mm of pipe and the relief valve insulated.
• Tempering valve. Required on every new or replacement installation: 60 degrees in the tank, no more than 50 at the tap.
• Time. A like-for-like swap of an outdoor electric tank usually takes two to three hours; allow half a day to a day for a new circuit, a slab or a new position.
• Switchboard. Older boards often need a safety switch (RCBO) for the new circuit; we check this on every site visit. See switchboard upgrades and RCBOs.

How we fit in, and our plumbing partner

Sun Connect Solar is a solar, battery and EV charger electrical contractor. On a heat pump job we do the electrical side: the dedicated circuit, the isolator, the timer or the link to your Sigenergy or GoodWe system, and the switchboard work. The water side is done by a licensed local plumbing partner. If you tick the box in the calculator, we pass your details to that partner so they can quote the heat pump and the plumbing; we may receive a referral fee for the introduction, which does not change the price you pay. If you do not tick it, your details stay with us and we only send you the result and this guide. Most of our customers add the heat pump as part of a solar and battery system so it runs on their own daytime power.

Hot water is usually the first gas appliance to go; the cooktop is the second. The getting off gas guide and induction cooktop switchboard checker covers the circuit, the switchboard and who may disconnect the gas.

Which circuit and tariff the heat pump sits on matters as much as the unit: see controlled load 1 vs 2 and time-of-use in the Essential Energy area.

In a new build the heat pump is also a BASIX decision: see BASIX, solar and batteries for a NSW new build.

Questions we get asked

What size hot water heat pump do I need?

Work on about 50 litres of hot water per person per day with roughly a day and a half of storage, because heat pumps reheat slowly (about 1 to 2 litres a minute against 3 for an electric element). One or two people: 160 to 200 L. Three or four: 250 to 300 L. Five or more: 315 to 400 L. Go up a size for long showers, a spa bath, teenagers or regular guests. The calculator on this page gives you the size and the daily energy for your household.

Are hot water heat pumps noisy?

They make a fan-and-compressor hum while heating. Published levels for decent units are 37 to 50 dB(A): split systems such as Sanden, Reclaim and Thermann X sit at about 37 dB, most all-in-one units at 43 to 48, and the loudest mainstream units at 50. Installed noise is a little higher than the lab figure because walls reflect sound. Keep the unit away from your own and your neighbour’s bedroom windows, out of corners and alcoves, and run it on a daytime timer; NSW noise rules say a heat pump water heater must not be heard in a neighbour’s bedroom before 7am or after 10pm on weekdays (8am at weekends).

Do heat pumps work in winter in the Northern Rivers?

Easily. Our winter mornings are mild, and a heat pump heating water in the middle of a Northern Rivers winter day is running in 15 to 22 degree air, near the top of its efficiency curve. Units rated to minus 5 or minus 10 degrees never get near their limit here. The one thing to check is the upper limit: a unit rated only to 35 degree air can struggle on a hot inland afternoon.

Can I run a heat pump hot water system from my solar panels?

Yes, and it is the best way to use one. A heat pump draws only about 0.5 to 1 kW while heating, against 1.8 to 4.8 kW for an electric element, so a 6.6 kW solar system carries it with room to spare. Set the built-in timer (or a timer fitted by the electrician) to run from about 10 or 11am for three to six hours, and move the circuit off the old overnight off-peak supply so it can run in daylight. Some units (Emerald, Haier) can follow surplus solar automatically, and a Sigenergy or GoodWe home energy system can switch a heat pump circuit on when the panels are exporting.

What rebates are there for a hot water heat pump in NSW in 2026?

Two. Federal small-scale technology certificates (STCs), claimed by the installer and taken off the price: in our climate zone a mainstream 270 L unit earns about 15 to 17 STCs for a 2026 install, worth a few hundred dollars depending on the certificate price, and the number steps down every 1 January (about 12 to 14 in 2027). And the NSW Energy Savings Scheme hot water upgrade: an upfront discount, indicatively up to about $640 when you replace an existing electric heater and up to about $330 when you replace gas, through an installer working with an accredited certificate provider, with a minimum co-payment and a nomination form signed before the work starts. It applies to replacements only, not new builds. The federal Cheaper Home Batteries rebate covers batteries, not hot water.

CO2, R290 or R134a: which refrigerant is better?

CO2 (R744) units (Sanden, Reclaim, Thermann X) make very hot water, keep working in cold air and are the quietest, but cost more and need a split installation. R290 (propane) is now the standard in mid-range all-in-one units (iStore, Rheem AmbiPower, Solahart Atmos Eco, Rinnai, Haier and others), efficient and low-impact in the small sealed charge they use. R134a is the older refrigerant being phased out; R513a is a lower-impact blend Rheem and Solahart moved to as a halfway step. In our mild climate CO2’s cold-weather edge is not needed; its real benefits are quiet running, hot delivery and long warranties.

Do I need a plumber or an electrician to install a heat pump?

Both. A licensed plumber does the water side (tank, valves, the tempering valve that keeps tap water under 50 degrees, the drains) to the plumbing standard and the maker’s manual, or the warranty and the NSW incentive are at risk. A licensed electrician provides the dedicated circuit and isolator (10 to 15 A for most units, 20 A for a few with larger elements) and, if you want to run it on solar, moves it off the old off-peak circuit. We are the electricians; we work with a licensed local plumbing partner for the water side.

Which is better: a heat pump or solar hot water panels on the roof?

For most homes today, a heat pump plus solar electricity panels. Roof hot-water panels only make hot water; the same roof space covered in solar electricity panels can run the heat pump, the house, a battery and a car. A heat pump also qualifies for STCs and the NSW discount, and it is cheaper to replace when it reaches the end of its life.

Does Sun Connect Solar install heat pumps?

We are solar, battery and EV charger electricians. For hot water heat pumps we provide the electrical side and work with a licensed local plumbing partner for the water side; if you ask us to, we pass your details to the partner so they can quote, and we may receive a referral fee for that introduction (it does not change your price). Most of our customers add the heat pump as part of a solar and battery system so it runs on their own daytime power.

Sources

SolarQuotes heat pump hot water guide and comparison table (updated 7 October 2026), SolarQuotes brand reviews (iStore, Reclaim, Sanden, Stiebel Eltron, Rheem, Solahart, Thermann, Hydrotherm, Midea, Evoheat, Quantum), SolarQuotes noise and sizing articles; makers’ data sheets and warranty documents (iStore, Reclaim Energy, Sanden, Stiebel Eltron, Rheem, Solahart, Emerald, Chromagen, Rinnai, EcoGenica, Evoheat, Reece Thermann, Haier, Apricus); CHOICE heat pump test listings; Clean Energy Regulator register of solar water heaters (May 2026) and heat pump zone map; NSW Government Energy Savings Scheme hot water upgrade page (February 2026) and IPART rule changes (1 July 2026); NSW Protection of the Environment Operations (Noise Control) Regulation; Essential Energy controlled load tariffs; Solar Victoria and Energy Safe Victoria installation guidance; Macquarie University refrigerant study. Full list with dates in our research note. Checked october 2026.

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