Understanding COP and Hot Water Savings with Gree WHIO

Hot water is part of everyday life, from morning showers to washing dishes. With the Gree WHIO Hot Water Heat Pump, heat pump technology can help reduce the electricity needed to heat your water. Understanding COP can help explain how those savings work.

What does COP mean?

COP stands for Coefficient of Performance. It measures how much useful heat a heat pump delivers for each unit of electricity it consumes.

A COP of 5.4 means that for every 1 kWh of electricity consumed, the system delivers approximately 5.4 kWh of heat. This is possible because a heat pump draws heat from the surrounding air and transfers it into the water.

Gree WHIO’s published COP of 5.4 is measured under specific test conditions: outdoor air at 20°C dry bulb and 15°C wet bulb, with water heated from 10°C to 55°C. It is a reference point for efficiency, rather than a constant level of performance throughout the year.

What could this mean for your household?

Consider an illustrative household of four, with each person consuming 45 litres of hot water a day. The example assumes a daily water heating requirement of 11.5 kWh and an electricity price of $0.30 per kWh.

At a theoretical COP of 5.4, the comparison looks like this:

Theoretical comparison based on a daily water heating requirement of 11.5 kWh, electricity at NZ$0.30 per kWh and 365 days per year. Figures are rounded. Actual COP, running costs and savings vary with operating conditions, water temperature, ambient temperature and usage. This calculation does not adjust for seasonal weather changes or include purchase and installation costs.

Under these assumptions, the calculated saving is approximately $1,026 per year, or 81% of the electricity cost for water heating. This does not represent a reduction of 81% in your total household electricity bill.

Why actual savings vary?

COP changes with operating conditions, including outdoor air temperature and the temperature of the water being heated. Household hot water consumption and electricity tariffs also affect running costs.

For example, if the average COP were 3.0, the same daily heating requirement would need approximately 3.83 kWh of electricity. The calculated annual cost would rise to around $420, with a saving of approximately $839 compared with the standard electric cylinder in this example.

Explore more efficient water heating

Whether you are replacing an existing cylinder or planning a new home, Gree WHIO offers an opportunity to reduce the electricity consumed for water heating.

Explore the Gree WHIO Hot Water Heat Pump and talk to your local Gree supplier about suitability for your household.

Figures are theoretical estimates based on the assumptions above, with annual costs calculated over 365 days and rounded. The calculation does not adjust for seasonal weather changes or include purchase and installation costs. Actual performance, running costs and savings will vary.

COP and test conditions: Gree WHIO product information.