Doug Leeder, Waiotahi Valley, Opotiki


System Details

Doug Leeder was expanding his herd and building a new milking shed in early 2009. Hot water demand would increase substantially and the most efficient, economic approach was needed. Doug compared the cost benefit and ROI of diesel, gas and solar systems. The solar system with electric backup came out far ahead although it felt like a risk.

Two 600 litre cylinders were installed with 8 high efficiency solar panels to heat the water. 3 electrical elements provide backup heating in each tank.
The system gives Doug 600 litres at 80°C to wash the plant after morning milking and 600 litres at 80°C for the vat every day. The farm uses a standard dairy cleaning mix with an alkali wash twice a week. There are no grading or washing problems. All this is controlled automatically from a clear VDU display in the tank room.

Doug: “It’s an easy system to run. I can self diagnose problems and monitor the water temperature simply every morning. During the miserable August 2010, the solar system heated 600 litres to 70°C every day with air temperature never rising above 17°C.”

The Numbers:

1200 litres of water at 80°C every day, 9 months a year.
November to March, the solar system provides 90% of hot water needs.
5 year warranty. Built in fail-safe frost protection.
Short ROI and excellent Net Present Value.
Flexible and custom designed for each dairy shed.
Far more economical than diesel, gas or electrical water heating, now and in the future.


Doug Leeder, farmer - “Everyday we walk into the shed and look at the temperature dial and know that’s more dollars we save. A solar system was not front of mind when we planned the new shed but now it’d be first on the list for the future. The system has exceeded my expectations with a ROI of only 5.5 to 6 years, better than what was calculated at the beginning.”

Cameron Mitchell, farm manager - “The concept is good. If you’re saving money it’s got to be good. 70°C in the bad weather of August 2010... great!”

Erik Codlan, farm electrician at Jayar Electrical - “I think it’s great. Marvellous. A hell of a cost saving if it’s used properly. Other farmers will think of this with electricity costs being looked at.”


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