High-wall heat pumps for New Plymouth homes

A high-wall suits most New Plymouth rooms, and three things decide whether it suits yours: whether one unit can reach the whole space or the layout closes it off, whether the room needs more capacity than its floor area suggests because the ceiling is high and the walls are mostly window, and how much salt the westerly delivers to your particular address.

How much does a high-wall heat pump cost in New Plymouth?

Fitted, a bedroom or small room runs about $2,200 to $3,200. A main living area is $3,000 to $4,500, and a large or open-plan space $4,000 to $6,000. That's roughly 2.5kW, 5 to 6kW and 7 to 8kW of capacity.

Those are prices for the finished job. They cover the indoor and outdoor units, the brackets, the insulated pipework, the drainage, the electrical connection and the labour to fit it tidily and test it. A cheaper figure online is the box on its own, and you'll still need someone to put it up.

The rest comes down to how hard the job is. It goes quickest and cheapest when the outdoor unit can be mounted on the outside of the very wall the indoor head is on, leaving the pipework a single wall to get through. Taking it round the house or up through a ceiling adds materials and hours.

What else moves it

Corrosion-resistant brackets and a coated outdoor unit are worth having anywhere the westerly reaches, which is further inland than most people expect. And where the switchboard has nothing spare on it, a new circuit goes on the quote, which the older weatherboard places through Welbourn and Spotswood often need.

Put your room through the sizing calculator for a capacity and a figure, or read the installation cost page for what pushes a quote around.

What the Tasman westerly does to an outdoor unit

There's nothing between New Plymouth and Australia, so the wind that arrives here has crossed open ocean the whole way and it's carrying salt when it lands.

The outdoor unit is a copper coil threaded through hundreds of thin aluminium fins, and those fins are how it sheds heat outside. Salt settles on them and works its way into the metal, and once they've gone chalky and started to crumble there's less left to shed heat through. The unit runs longer for the same warmth and the power bill follows it.

What's different about Taranaki is how far that reaches. On a sheltered coast the salt drifts a few streets and stops. Here it's driven, so Fitzroy, Moturoa and the streets nearest the water get the worst of it but Bell Block gets a share too, and plenty of houses that don't think of themselves as coastal are still getting a dusting every time it blows hard.

Three things deal with it. A coated unit and corrosion-resistant brackets cost a little more and last considerably longer. A position on the sheltered side of the house rather than the exposed seaward wall keeps most of it off in the first place. And a rinse with fresh water every few weeks through summer clears what does land before it has time to bite, which takes two minutes with a hose and is the single most useful thing you can do for it.

The unit still needs air moving around it and room for someone to stand and do the yearly service, so tucking it behind a fence to hide it from the wind creates a different problem.

Sizing one for a weatherboard bungalow

A lot of Taranaki housing is older single-glazed weatherboard, and those rooms lose heat faster than their floor area suggests. The published guide is 2.5kW for a bedroom, 5 to 6kW for an ordinary lounge and 7 to 8kW for a large or open-plan space, and an older place wants the step up.

Two features of those bungalows make the difference. The ceilings are high, so warm air pools above head height where it does nobody any good. And the walls are often mostly window, and a single pane sheds heat roughly ten times faster than the wall around it, so the room is losing warmth about as fast as a modest unit supplies it.

That's why a floor console comes up so often in those houses. It puts the same heat in at skirting level, so it reaches you on the way up rather than after it's collected at the ceiling.

The newer builds out at Bell Block are the opposite problem and an easier one. Fewer walls, one big space, decent insulation, so a single well-sized high-wall carries it.

Buying big isn't the safe way out of any of this. Too much capacity and the unit reaches temperature in a rush and shuts off before it's pulled any moisture from the air, which matters here because coastal Taranaki is damp and a room that's warm and still clammy is the usual complaint.

Will one heat the whole house?

With the internal doors open, one in the main living area covers a compact house better than people expect, and in a newer open-plan build it's often the whole job.

Where it struggles is a closed-off room down a hallway, because warm air can't turn a corner. If the bedrooms matter, a multi-split runs several indoor heads off one outdoor unit for about $6,000 to $12,000 depending on how many rooms, which saves bolting three separate boxes to the side of the house. A ducted system feeds every room through ceiling vents from about $12,000 and shows nothing but the grilles.

For a big open room where a wall unit would look bulky, a ceiling cassette sits flush and blows four ways instead of from one end.

Whichever you go with, it's reverse-cycle, so it cools in summer off the same box. It also pulls moisture out while it runs, and in a climate as damp as this one that's worth as much as the temperature is.

Still weighing it up? Types of heat pump puts a high-wall beside a floor console, a ceiling cassette, a multi-split and ducted, and heat pump installation covers how the day runs. For a number on your own room, get a free quote.