The complete guide to hot water heat pumps in New Zealand (2026)

Everything you need to know about heat pump water heaters, including how they work, costs, savings, installation, maintenance and whether they're right for your home.

Thinking about a hot water heat pump?

If you're looking for ways to reduce your household power bills, your hot water system is one of the best places to start.

For most New Zealand homes, water heating is the second-largest energy user after space heating, accounting for around 30% of a home's electricity consumption. That means an inefficient hot water system could be costing you hundreds – or even thousands – of dollars more than necessary over its lifetime.

A hot water heat pump, also known as a heat pump water heater, is one of the most energy-efficient ways to heat water. By using electricity to transfer heat from the surrounding air rather than generating heat directly, these systems can use up to 75% less electricity than a conventional electric hot water cylinder.

Whether you're replacing an ageing electric cylinder, switching from gas, or building a new home, this guide explains everything you need to know before making the change.

What is a hot water heat pump?

A hot water heat pump is a storage hot water system that uses heat pump technology to heat your water.

Rather than creating heat using an electric element (like a traditional cylinder), it extracts heat from the surrounding air and transfers it into the water stored in the tank.

Think of it as a refrigerator working in reverse. A fridge removes heat from inside and releases it outside. A hot water heat pump captures heat from the outside air and transfers it into your hot water.

Because moving heat requires much less energy than creating it, the system is significantly more efficient.

How does a hot water heat pump work?

A heat pump water heater operates in four simple stages:

1.       A fan draws in outside air.

2.      A refrigerant absorbs heat from that air.

3.      The refrigerant is compressed, increasing its temperature.

4.      The heat is transferred into the water stored in the cylinder.

Even on cool days, the outside air contains enough heat energy for the system to operate efficiently.

Most modern units also include a built-in electric booster element that automatically provides additional heating if unusually high volumes of hot water are needed.

How efficient are heat pump water heaters?

Efficiency is measured using a Coefficient of Performance (COP).

A standard electric hot water cylinder has a COP of approximately 1, meaning every unit of electricity produces roughly one unit of heat.

Modern heat pump water heaters can achieve COP ratings above 5, meaning they can deliver more than five units of heat for every unit of electricity consumed under ideal conditions.

In practical terms, many New Zealand households reduce the electricity used for water heating by up to 75% after upgrading.

How much can you save?

The exact savings depend on several factors, including:

·       Your current hot water system

·       Household size

·       Hot water usage

·       Local electricity or gas prices

·       Climate

All Ecobulb customers receive personalised savings estimates through a free Hot Water Assessment.

Examples include:

·       Homes replacing electric cylinders saving several hundred dollars each year.

·       Homes replacing bottled LPG systems saving well over $1,000 annually.

·       Homes replacing mains gas often achieving significant annual reductions in excess of $1,500 a year.

Over the lifetime of the system, total savings can amount to tens of thousands of dollars.

How much does a hot water heat pump cost?

The total installed cost depends on:

·       Whether you're replacing gas or electric hot water

·       Installation complexity

·       Existing plumbing

·       Electrical requirements

While the upfront investment is generally higher than a standard electric cylinder, the lower running costs often result in a payback period of around two to five years, depending on your household's water use.

After that, the ongoing savings continue year after year.

Heat pump water heater vs electric hot water cylinder

Feature	Heat pump water heater	Electric cylinder	Gas (bottles)	Gas (piped)
Running costs	Very low	High	Very high	Very high (includes gas supply charges)
Energy efficiency	Up to 75% lower electricity use	Standard	Low	Low
Carbon emissions	Much lower	Higher	Higher	Higher
Lifespan	10–15+ years	Similar	Similar	Similar
Maintenance	Low	Low	Higher	Low
Upfront cost	Higher	Lower	Lower	Lower (if applicable)

Although an electric cylinder and gas systems usually cost less to install, the ongoing electricity savings make a heat pump the more economical choice over its lifetime.

Do heat pump water heaters work in winter?

Yes.

This is one of the most common questions homeowners ask.

Modern heat pump water heaters are specifically designed to operate in New Zealand conditions, including cold South Island winters.

Even when the outside temperature drops close to freezing, there is still enough heat energy in the air for the system to operate efficiently.

For periods of unusually high demand, the built-in electric booster automatically provides additional heating if required.

Are heat pump water heaters noisy?

Modern systems are surprisingly quiet.

Most produce a sound level similar to an outdoor air conditioning unit.

When installed in an appropriate location, the operating noise is generally unobtrusive.

The Emerald Pro hot system that we install also includes a quiet function if required.

Where can they be installed?

Most heat pump water heaters are installed outdoors.

They can replace:

·       Electric cylinders

·       Gas storage systems

·       LPG systems

Some homes also install them in well-ventilated garages or utility areas where appropriate.

A professional installer will recommend the best location based on airflow, access and plumbing requirements.

Do they require maintenance?

Heat pump water heaters require relatively little maintenance.

Periodic servicing may include:

·       Washing the unit with your garden hose

·       Cleaning air filters

·       Checking refrigerant components

·       Inspecting electrical connections

·       Testing safety valves

·       General performance checks

Following the manufacturer's maintenance recommendations helps maximise efficiency and system lifespan.

Are they suitable for every home?

Most homes are excellent candidates.

A professional assessment considers factors such as:

·       Existing hot water system

·       Household size

·       Available installation space

·       Electrical supply

·       Plumbing configuration

·       Expected energy savings

Ecobulb's Hot Water Assessment provides homeowners with a personalised suitability score, estimated annual savings and expected payback period before making a decision.

What should you look for when choosing a heat pump water heater?

Not all systems are created equal.

When comparing products, consider:

·       Energy efficiency (COP)

·       Warranty

·       Recovery rate

·       Tank capacity

·       Operating temperature range

·       Refrigerant type

·       Smart controls or Wi-Fi connectivity

·       Installer experience

·       After-sales support

The cheapest option isn't always the best value over the life of the system.

Frequently asked questions

How long does a heat pump water heater last?

Most quality systems are designed to provide reliable operation for 10–15 years or more, depending on maintenance and usage.

Can I replace my existing hot water cylinder?

Yes. Heat pump water heaters can replace most electric, gas and LPG hot water systems.

Do they work on cloudy days?

Yes. Unlike solar hot water systems, they do not rely on sunlight. They extract heat from the surrounding air.

Are they suitable for large families?

Yes. The correct tank size and recovery rate should be selected based on your household's hot water demand.

Can I control the system from my phone?

Many premium systems, including the Emerald Heat Pump Water Heater, offer Wi-Fi connectivity that allows you to monitor and control settings using a smartphone app.

Why more New Zealand homeowners are choosing heat pump water heaters

With electricity prices continuing to rise, homeowners are increasingly looking for long-term ways to reduce energy costs without sacrificing comfort.

A heat pump water heater offers:

·       Up to 75% lower electricity use for water heating

·       Lower energy bills

·       Reduced carbon emissions

·       Reliable hot water all year round

·       Low maintenance

·       Long operating life

·       Excellent long-term return on investment

For many households, upgrading to a heat pump water heater is one of the most effective energy-saving improvements they can make.

Find out how much you could save

Every home is different, which is why the best place to start is with a personalised assessment.

At Ecobulb, we provide a FREE, no-obligation Hot Water Assessment that estimates your:

·       Annual energy savings

·       Home suitability score

·       Expected payback period

Our team will help you understand exactly how much you could save by switching to an Emerald Heat Pump Water Heater, giving you the information you need to make a confident, informed decision.