With energy prices constantly on the rise, there is no better time than now to invest in alternative efficient clean energy. Within the last ten years the cost of electricity in New Zealand has increased by as much as 84% and continues to rise. With an abundant resource like the sun and smarter technologies for heating and lighting, we can use less energy and provide more options for you without compromising the Earth, or your way of life.

People are choosing clean green technologies…

  • Hot Water Heat Pumps – Use very little energy and heat from the ambient air to provide hot water for your home.
  • Heating and Cooling – You can also use your hot water heat pump as a space heater by utilising cassettes in your ceiling and/or radiators.
  • Solar Power – Generate your own energy needs and have the ability to feed excess power back to the grid.
  • Lighting solutions
  • Energy management systems


11 + 15 =


What sort of result can we expect from having solar power?

Many of our customers have drastically reduced their power bill. Your results however will depend on your current electricity usage and the size of the solar power system installed.

What do I need to do to maintain the solar power system?
Not Much. Our systems are virtually maintenance-free. There are no moving parts to break down and all the components are very high quality with warranties from 5 to 25 years. All you need to do is keep the panels free from obstruction (for example: heavy dust, leaves, etc). Normally a gentle hosing down is all that is required. Ask us about our maintenance options available.
Will the system work in a blackout?
Unfortunately no. The solar power systems are required by the electricity safety regulations to switch off when there is a black-out. This prevents the inverter feeding power into the ‘dead’ grid while technicians are working on the lines. On the plus side, as more and more homes install our clean energy systems they will stabilise the grid, helping to prevent black-outs caused by over-demand.
Can I install the solar power equipment myself?
No. The system MUST be installed by our licensed electricians and certified installers. 
How much power will I save?
The power you save depends on the size of the system you install and can then be improved by using timers on appliances, or energy management system.
How much money will I save?
The financial savings depend on your electricity tariff as well as power saving achieved. 
What size system will work for me?

This heavily depends on three factors:

1. How much power you use?
2. How large is your roof
3. How much money you want to spend.

To formulate how much power you use, check the “KwH usage” on your energy bill.

Do you offer Finance?
Yes. Our staff can facilitate this with Q card and help set up loans with other lending facilities. Contact us to find out more.

Hot Water Heat Pump

How do hot water heat pumps work?

Unlike a conventional electric water cylinder which uses electricity to heat water directly, heat pumps use a small amount of electricity to operate a pump that circulates a refrigerant around the system. This refrigerant picks up heat from the air and transfers it to the water. They are approximately three times more efficient than a conventional electric storage water heater.

There are several steps in the water heating process: 

  1. Liquid refrigerant passes through an evaporator where it picks up heat from the air and becomes a gas.
  2. The gas refrigerant is compressed in an electric compressor. Compressing the gas causes its temperature to increase so that it becomes hotter than the water in the tank.
  3. The hot gas flows into a condenser, where it passes its heat to the water.
  4. The gas then flows into an expansion valve where its temperature drops and it returns to liquid form

Heat pump water heaters are effective because they use a refrigerant with a very low boiling point to allow the transfer of heat between the air and the stored water. As long as the outside temperature is higher than the cold refrigerant, the heat pump will absorb heat and be able to move it to the water.

Fresh air needs to flow across the evaporator to enable heat to be absorbed continuously. A fan is used to assist air flow and remove the cooled air. A ventilated space is necessary for the evaporator to extract heat effectively.

A heat pump uses electricity to drive the compressor and the fan instead of using electricity to heat the water directly. The heat pump is able to transfer heat energy from the surrounding air to the water, which makes it highly efficient. How much heat is transferred depends on the ambient temperature.  For example when the air temperature is 15 degrees Celsius and the desired water temperature is 60 degrees Celsius, the heat energy transferred into the water is typically around three times as much as the electrical energy used.

How does a hot water heat pump save up to 75% on my hot water consumption?

Hot water heat pumps are very economical to operate compared to gas powered water heaters and conventional electric element water heating (where power is being pushed through an electric resistance element).

  • Depending on the hot water usage, ambient air temperature and humidity, your hot water heat pump will use about 3kW/h per day but will only likely need to run for about 2 hours per day.
  • So for every $1 you spend on running your hot water heat pump you will get between $3-$4 of hot water. 
Is a hot water heat pump a good solution for New Zealand, both on grid and off grid?

There are currently over 2,000,000 separate domestic water heaters installed in New Zealand houses, apartments and other accommodation.

More than 70% of dwellings in New Zealand still have electric element hot water heaters. If the power from these water heaters could be cut by 75%, New Zealand could make a huge step forward in reducing our energy requirements.

Is a hot water heat pump water efficient?

Depending on the air temperature you are likely to only need to run your hot water heat pump for two or three hours a day.  It will turn on when the water temperature in the tank is low enough to trigger the controller to turn it on.  It is also better for the heat pump to keep running periodically rather than have long periods where it is shut down.

What is the life expectancy of a Hot Water Heat Pump?

Most stainless steel condenser water tanks last more than 20 years.  The full life span will depend on your water quality – the purer the water, the longer the life.  Our units are warranted for 2 years. The compressor in the Heat Pumps that we supply are high quality rotary type compressors, similar to the compressor in your refrigerator and should have a similar life span.

Can I save money by operating a heat pump at night on Off-Peak Tariffs?

The heat pump water heater is able to operate at night because it can extract solar energy from the ambient air rather than relying on daylight hours (like Solar Photovoltaic Panels or Evacuated Tubes do). Night time off peak electricity tariffs are often better than daytime tariffs (ask your electricity provider for rates) so it makes sense to heat your hot water at night.

As long as your normal daily water use is less than the water capacity of the heat pump you have purchased, the hot water produced during the nightly Off-Peak Tariff period (approx 3-4 hours depending on your ambient water and air temperature) will be available to you throughout the following day. Not only does the heat pump save you money, it can also help make money. If you have installed solar photovoltaic panels for power generation during the day, you can transfer your water heating power needs to the night.

How might I compare the performance of a hot water heat pump to other products?

The following graph from New Zealand’s Parliamentary Services demonstrate the running cost advantages of a hot water heat pump:

running cost

What is the annual operating cost of a heat pump?

Based on user experience and test data, the annual power usage for an average family using around 200 litres per day will be around 1,000 kW/h in a Southern climate, less for Northern climates. Cost estimates would then be as follows:

  •  If you used the power from a 1 kW PV panel system during the day with an 8 cents per kW/h tariff, then the cost would be only around $80pa. 
  •  If you used an off-peak tariff at night of 16 cents per kW/h, then the cost would be around $190 adding on 20% extra run time for the 10 degree average power air temperature at night. If you used a day-time tariff of 24 cents per kW/h, then the cost would be around $240 with 20% shorter run time for the 10-degree average higher air temperature during the day.

The running costs of an electric element water heater will be up to 4 times more. The running costs of bottled gas average around 3 times the price of natural gas.

Can a hot water heat pump be used in commercial or larger scale installations?
Depending on your site, two or more of our standard models can be easily grouped together to handle your commercial, sporting or community hot water requirements.  We can design a system to fit with your current solar photovoltaic or hot water system also.  By getting your hot water heat pump to do the work during winter it can often cut your winter water heating bills in half.
What is an all-in-one (or integrated) unit?

The all-in-one unit includes the hot water cylinder and the hot water heat pump.  So the condenser and coils sit on the top of the cylinder and come as one upright unit.

What is a bolt-on unit (or split system)?

The bolt-on units allow you to retain your existing cylinder and have the hot water heat pump unit installed outdoors.

Is a hot water heat pump easy to install?

Yes, for a typical installation your plumber will take around 3 hours.  A concrete plinth is required (and in some cases where the brackets are not already in place to tie the unit back you may wish to cement a couple of poles into the ground to enable the seismic straps to tie to these).  Other than that all you need to ensure is good airflow for your unit.

There are many different configurations depending on your preference for your home or your new home/business plans if you’re in the design phase such as:
–        The units are normally installed outside which frees up your existing indoor cylinder space

–        A bolt on unit provides you with the savings but no disruption to your existing cylinder (if you have a good one that is not about to fail).

What do I need to take into account when considering where best to locate my hot water heat pump?

Hot water heat pumps operate most efficiently when placed outside because they need fresh air and plenty of ventilation. It’s possible to operate them inside but you need a well-ventilated space that has a constant supply of fresh air for a heat source and so the cold air produced can be removed. Heat pumps should not be placed in a heated space because they cool the surrounding air and will have to work harder to keep the water warm.

Try to have your system installed as close as possible to your main areas of hot water use (ie bathrooms, laundry, kitchen) so keep pipe lengths short and minimise water and heat loss. This may be the basis of choosing between an all-in-one unit or a bolt on system.

Will my hot water heat pump make any noise?

Heat pumps make a low humming sound, similar to a refrigerator or air conditioner. Noise levels are generally less than 50 decibels at a distance of 1.5 metres (about the level of background noise in an average home). Properly located heat pumps are unlikely to cause noise problems, but it is advisable to install the system away from bedrooms and neighbouring properties to avoid potential issues. Different brands and models will have varying noise levels, seek one with a low decibel level. Noise impacts can be further reduced by locating the heat pump at ground level and facing the condenser fan discharge away from living areas and bedrooms.

What does a hot water heat pump do to my water pressure?

It will not change your water pressure.  It may however be a timely option to install a high pressure valve hit at the same time as installing your hot water heat pump if you’d like to improve your water pressure.

What general maintenance does a hot water heat pump water heater require?

Good airflow across the heat pump evaporator fins is essential for optimal operation of your hot water heat pump. We recommend brushing or hosing down the fins at least once every 6 months.

We also recommend that you release the pressure and temperature relief valve once every twelve months. To do this, simply gently raise and then lower the valve lever (positioned at the top of the tank near the hot water outlet). Refer to your Owner’s Manual for more details. Most tanks have a sacrificial anode to protect the metal hot water tank against corrosion. Have a licenced service person check the system and perhaps replace the anode every five years.

What do I do if my hot water heat pump has a problem?

Firstly, have you plumber check the unit. If the problem persists, Assist Energy Ltd if we installed it. Please have the serial number ready so that we can check for warranty verification purposes.

What is the difference between a kW and kWh?

The kilowatt-hour (symbolized kWh) is a unit of energy equivalent to one kilowatt (1 kW), which is a measure of power, expended for one hour. It measures energy used and will appear on your power bill as energy used per month.

A hot water heat pump will typically use 1 kW of electrical power to provide 2.5-3.5kW of heat depending on the ambient air temperature. The kW rating measures how fast the energy is being used.

Can I switch the system off?

If you are going away you can safely switch your heat pump off. The stored water may cool below 60 degrees Celsius while you are away. When you return, the water in the storage tank must be boosted to 60 degrees Celsius for 35 minutes before any hot water is used to kill any bacteria that may have grown. Warming this water may take a few hours.