Heat pump replacement and system upgrades

Usually not. A hydronic system has three parts: the loops in the floor, the manifold and controls, and the outdoor unit that heats the water. The outdoor unit is the part that wears out. The loops are cast in concrete and do not degrade; the manifold, valves and thermostats are usually fine or can be replaced individually.

Most of them are a day. Old unit off, new unit onto the same pad or brackets, flow and return reconnected, electrical checked, controls set up, system balanced and commissioned. Where it takes longer is when the new unit is a different size or shape, when the old pipework is corroded, or when the electrical supply needs rework.

Usually yes. We check the pipe condition, the insulation and the pad or brackets first, and price any replacement that is needed.

As a rule of thumb, once a unit is past about twelve to fifteen years and needs a major component — compressor, heat exchanger, control board — you are usually better off replacing it. Under that, repair is often the right answer and we will do the repair.

Generally yes. Efficiency has improved, and newer units have inverter compressors that modulate instead of cycling on and off, better defrost control, and controls that match the flow temperature to the weather. An old fixed-speed unit starts and stops frequently, which reduces its efficiency.

The New Zealand-built range from Hot Water Heat Pumps Ltd — the ‘U’ series for underfloor heating, from 10 kW to 28 kW and beyond, with single-phase and three-phase options, and DuoHeat models that do floors plus pool or floors plus hot water from one unit. Built in New Zealand, supported here, with parts here.

A ‘Ub’ has the buffer tank and circulation pump built into the unit. A ‘U’ does not, so those are separate. On a replacement, the built-in version often makes the swap tidier and quicker — fewer things to find room for in the cupboard.

Frequently, and this is worth asking about before you order like for like. A DuoHeat unit can heat your floors in winter and your pool in summer, or your floors and your hot water cylinder all year. If you were ever going to add a pool or move hot water off an element, the moment you are replacing the heat pump anyway is the cheapest time to make it possible.

We will not know until we have done the heat loss calculation, and the answer is often no. Houses get insulated, windows get replaced, and the original unit may have been oversized. Sizing from the old unit can result in a larger unit than the house needs.

Modern units sit around 53–56 dB(A) at high speed measured at three metres, and inverter models spend most of their time well below that. Position matters more than the number — not under a bedroom window, not boxed into a corner with no airflow.

That is not a problem. We replace units of every brand and are not tied to one. The replacement is sized for your house, and the pipework it connects to is checked first.