Gary Moller's experience with rusting, corroding, fading solar water heating panels

This Sola60 panel (above) on our house looks impressive doesn't it? This is saving our family money on water heating and it is great for the environment. We are responsible citizens in this clean and green land. That was what we thought.

We noticed a steady drop off of peak water temperatures over a one year period, so I decided to investigate.

Here is another view:

There is extensive corrosion of the collector's absorber surfaces of this year old panel and what appears to be bleaching so that the surface looks grey-blue.

Here are the replacement panels that were supplied to us under warranty:

They are very smart looking. Now, here they are after a year:



These panels are bleached and have extensive corrosion (looks like sprinkled talcum powder) of the collector surface. And they now look kind of grey-blue which is not the best colour for absorbing solar heat.

Thankfully, they were replaced under warranty.

Here are the replacement ones seven months after being installed. Look carefully:

They are corroding again and we currently (30/11/2206) have a request with Sola60 to remove the system entirely from our roof because the warranty has not long to run and plenty of failed attempts have been had at resolving the problem. They were removed 24 January 2007.

Is there a problem?

The first clue that something may be amiss comes from the Branz report of Research Commissions:

"BRANZ Ltd identified that one of the biggest uncertainties in the cost/benefit analysis of solar water heating systems is the lack of reliable field data for system performances. Anecdotal evidence suggests that most existing systems fall significantly short of the calculated values used during the system design."

Could this shortfall be due to corrosion of the collectors?

How big is the problem? This is the question that I set out to answer by spending a few weeks trying to locate solar water heating systems in Central and South Wellington. This was not an easy exercise. I found several (Ours included).

A very rusty Sola60 solar water heating panel

Here is a selection of photos of some of the panels which the owners allowed me to inspect, and which I was able to get up close to without risking breaking my neck:

Look at this Sola60 panel: Just two and a half years old, with visibly faded strips and corroded in places. No building consent.

Will this panel last five years; let alone 10-15? Look closer:

Another example of something wrong with a Sola60 solar water heater

Here is another Sola 60 installation that shows deterioration of the collector surfaces (Please note the dates of the photos (31/03/2007)

Three Sola60 solar water heating panels 2.5 years old

This 2.5 year old array of Sola60 panels appears to be barely working, despite the cloudless day (Refer next three photos):

More corroding Sola60 solar water heating panels

When was the last time you looked closely?
The first two photos are of a Sola 60 installation which shows visible "discoloration" of the collector surface.

A rusty Sola60 just one year old

These two photos are of a Sola60 panel that is just one year old. The elderly couple spent precious savings with the intention of making a meagre pension for further.

No building consent.




This panel was inspected by a Branz researcher who said nothing of this corrosion, leaving this elderly couple with the impression that their system was in perfect condition.

• Solahart and Sola60 feature prominently. This is only because I have not found many other brands. My findings are not necessarily representative of the industry.

A corroding Sola60, just two years old, no building consent

Here is a Sola60 panel that is just two years old.


No building consent.

Sola60 - four years old

If you have an example of a good or bad solar water heating setup, then write to me here. Please include digital photos and contact details to verify the details.

This Sola60 panel is a little over four years old and is covered by what looks like white talcum powder.

Here is another view of the panel above: This has no lagging at all. It faces west, so it is only getting full sun later in the day and very little at all during winter months. It should be facing north.




The panel temperature sensor was hanging loose. It is possible that this panel has never worked due to this loose sensor, the absence of lagging and because it is facing the wrong way to the sun.