High-wall heat pumps for Rotorua homes
The slim unit up near the ceiling, with its outdoor half on the other side of the wall. It's the cheapest type to buy and to fit, and in most Rotorua houses one in the living room is all that goes in.
A high-wall suits most Rotorua houses. Whether it suits yours comes down to three things, and the brand isn't one of them: whether it's big enough for how fast your room loses heat on a frosty morning, whether the outdoor unit is built to survive the sulphur in the air, and whether there's a spot for it out of the frost that someone can still get to for a service.
How much does a high-wall heat pump cost in Rotorua?
Supplied and fitted, a bedroom or small room runs about $2,500 to $3,500. A main living area is $3,200 to $4,800, and a large or open-plan space $4,500 to $6,500. In capacity that's roughly 2.5kW, 5 to 6kW and 7 to 8kW.
Those are finished-job prices. They take in the indoor and outdoor units, the brackets, the insulated pipework, the condensate drain, the electrical connection and the commissioning at the end. A figure online that looks a lot cheaper is usually the box on its own, with the fitting still to come.
What separates one quote from another is nearly always the install rather than the unit. If the outdoor half can go straight through the wall behind the indoor head, that's the quickest version of the job there is. Take it round the house or up into the roof space and there's more pipework to buy and more hours to pay for.
What else moves it
A corrosion-resistant outdoor unit costs a little more than a standard one, and on an exposed site it's the difference between one that lasts and one that doesn't. Electrical work is the other one: a new dedicated circuit or a switchboard upgrade adds cost, though plenty of installs just use the capacity that's already on the board.
Put your own room through the sizing calculator for a capacity and a price, or read the installation cost page for what pushes a job up or down.
What Rotorua's sulphur air does to the outdoor unit
The outdoor unit is a copper coil threaded through hundreds of thin aluminium fins, and those fins are how it dumps heat outside. Rotorua air carries geothermal moisture and sulphur, and sulphur works into aluminium and corrodes it from the surface in. Once the fins go chalky and start crumbling there's less metal left to shed heat through, so the unit works harder for the same warmth and the power bill climbs with it.
No brand is immune, because they all use the same thin aluminium. What changes is the coating. Blue-fin and gold-fin coils put a treated layer over the metal, and your installer specifies one as a matter of course on an exposed site rather than as an upgrade you have to ask for.
How exposed you are moves street by street rather than suburb by suburb, which is why it gets looked at on site. Out on the lakeside subdivisions there's salt in the air on top of the sulphur, and the two together are harder on a coil than either one alone.
Position helps as much as coating. Out of the worst of the drift, with air around it so it can breathe, and somewhere a technician can actually stand for the yearly service, because a coil that gets washed down once a year lasts longer than one that never does.
Sizing a high-wall for a cold, damp Rotorua morning
Rotorua drops below freezing more often than most of the country, and the air is humid with it. That combination is harder on a heat pump than plain cold, because the unit is pulling the room up to temperature and drying it out at the same time.
The published guide is 2.5kW for a bedroom or study, 5 to 6kW for an average lounge, and 7 to 8kW for a large or open-plan space. An older single-glazed timber bungalow through the western suburbs loses heat faster than a newer insulated place of the same floor area, so the same room wants the higher figure.
Get it wrong in either direction and you feel it. An undersized unit runs flat out on the coldest mornings and never quite wins the room. An oversized one heats fast, shuts down before it's pulled much moisture out, and leaves you warm and still clammy. The windows tell you which one you've got.
Your installer settles the figure on site against floor area, ceiling height, glazing, insulation and how exposed the place is.
Where a high-wall heat pump goes
Inside, the head wants a clear stretch of wall up high with the room opening out in front of it. Aimed into a doorway or across the back of a sofa it warms the air right around itself, reads that as the room being up to temperature, and backs off long before it is.
In the older bungalows the usable wall is often the only one without a window, a chimney breast or a sloping ceiling in the way, and it's rarely the one you'd have picked. Take it anyway. An awkward position that throws air down the length of the room beats a tidy one that leaves half of it cold.
Outside, frost decides it. Cold air pools on low ground overnight, so an outdoor unit sitting at ground level in a hollow starts its morning in the coldest air on the property and spends longer melting frost off its own coil instead of heating the house. Up on brackets or a stand, clear of the low spot, with somewhere for the meltwater to drain away.
Get that wrong and the symptoms read like a faulty unit: longer and more frequent defrosts, ice building on the base, and a house that's cool by morning. Get it right and the same equipment simply works.
One high-wall, or more than one?
One unit in the main living area with the internal doors open carries a surprising amount of a compact house, and for one or two living spaces that's usually all that gets fitted.
It won't push heat down a hallway into the bedrooms, though. Warm air goes where it's blown and no further, so if the bedrooms matter you're looking at either a second unit or a multi-split, which runs several indoor heads off one outdoor unit and keeps one box on the wall instead of three. What that costs follows the number of heads and where they have to go, so it gets priced on the day rather than off a list.
In an older bungalow with high ceilings a floor console is worth pricing alongside, because it pushes warmth out at floor level where you feel it first instead of sending it straight up to the ceiling. In a newer place with room above the gib, a ceiling cassette or a ducted system does the whole house evenly.
A high-wall is reverse-cycle either way, so the box that heats you in July cools you in January, and it pulls moisture out while it does. That second half matters more here than the temperature does, because it's the damp that makes a Rotorua summer evening sticky and a winter room feel colder than the thermometer says.
Still weighing it up? The types of heat pump page sets a high-wall beside a floor console, a ceiling cassette, a multi-split and a ducted system, and heat pump installation covers how the day runs and what it costs. When you want a number, get a free quote.
What would a high-wall heat pump cost at your place?
Tell us the room and your suburb, and your local installer will come back with a price. Call 07 242 7180 or send it through.
Common questions about high-wall heat pumps
How much does a high-wall heat pump cost in Rotorua?
Supplied and fitted, about $2,500 to $3,500 for a bedroom or small room, $3,200 to $4,800 for a main living area, and $4,500 to $6,500 for a large or open-plan space. How far the pipework has to go, how easy the outdoor position is to get at, and whether the board needs a new circuit are what set the final figure.
Do I need a corrosion-resistant unit in Rotorua?
On an exposed site, yes. Sulphur in the air corrodes the aluminium fins on the outdoor coil, and once they go chalky the unit has less metal to shed heat through and costs more to run. A blue-fin or gold-fin coil costs a little more and lasts considerably longer. How exposed you are changes street by street, so it gets checked on site.
Will one high-wall heat the whole house?
It'll carry a compact house with the internal doors open, but it can't blow round a corner or down a hallway, so the bedrooms stay cold. Where you want those done as well, a multi-split runs several heads off one outdoor unit, and ducted heats every room evenly.
Why does my outdoor unit ice up on a frosty morning?
Every heat pump has to melt frost off its outdoor coil now and then, and it isn't heating the room while it does. A unit sitting low in a frost pocket starts colder, defrosts more often and takes longer to catch up. Raising it on brackets clear of the low ground, with a drain path for the meltwater, fixes most of it.
Get a high-wall heat pump priced for your room
You're connected with a local installer who specifies an outdoor unit that stands up to the sulphur and puts it somewhere it isn't sitting in the frost. Call 07 242 7180 or send through your details for a free quote.