KEY POINTS:
Solar water-heating systems installed in New Zealand are disappointing some homeowners - with limited power savings and problems including corrosion, leaks and bleached panels, which all affect performance.
Eric Jansseune, a Belgian solar engineer, said people had come to him for advice having spent thousands on under-performing installations.
Mr Jansseune, who now lives in New Zealand, said he spent 15 years in the solar industry in Europe. "We are making the mistakes they made there 20 years ago. There is a lack of expertise in the field."
Mr Jansseune cited a shortage of trained installers, problems with overheating or freezing, and product failures like corrosion or discoloration of solar panels.
Consumers were not given reliable data on how much energy they would actually save and many were left disappointed, he said.
Some systems were installed without good insulation, which led to heat loss, and Mr Jansseune was also critical of systems where the water cylinders were installed on top of roofs, where they lost energy at night.
He said only electrical back-up systems for solar water heating were subsidised, which discriminated against efficient alternatives like gas.
Remuera resident Richard Willis paid more than $50,000 to install 12 large solar panels on the roof of his new north-east facing home last December. "I knew it was a lot to spend but it was not all about trying to save on the power bill - it's being a responsible citizen."
However Mr Willis was shocked at how poorly the system was working now. It had provided ample hot water until about June but has since been of little use.
The set-up meant Mr Willis suspected it was now losing heat. "It was not installed correctly, there are non-insulated parts and it leaks."
Another Auckland consumer, who did not want to be named, had spent $3800 on her system, which installed last October and initially worked well. "But I only made savings when I was able turn off the hot-water mains."
When she used electrical back-up, the system did not seem to save her any money at all.
The woman said information surrounded solar systems was "a minefield" and confusing to the average householder. She had been told she could save close to 80 per cent on her power bills. "It's been a complete waste of money."
Brian Cox, executive officer Solar Industries Association, said most problems came down to misunderstandings between the purchasers and sellers. He said where people were not getting the results they had been told to expect, they should take a case to the small claims tribunal.
The association, which represented manufacturers, importers and installers of solar water-heating systems, wanted to know when things went wrong to try to find answers to fix them. Mr Cox fielded "about one complaint a fortnight out of an estimated 4000 systems installed in New Zealand homes each year".
He stressed that solar hot water should be regarded as a secondary source to supplement water heating.
Mr Cox did not blame underperformance on the products themselves but there had been cases of poor installation by plumbers not trained how to do it properly.
"For instance, if they are not put in with a decent controller you will not get good gains ... all systems, if properly installed, set-up and designed, will do the job."
Mr Cox said the systems were not maintenance-free and should be checked every five years.
The building code required that they lasted at least 15 years but should perform much longer.
"Some installed back in the eighties are still efficient."
The association ran an accreditation system for suppliers and installers, was preparing best practice advice, and had been involved with establishing a training course for solar water heating installers at the Waikato Institute of Technology.
