Frequently Asked Questions

How do vacuum tube solar panels compare with flat plates?

On a hot, sunny day, flat plate panels will produce the same amount of heat, more or less, as for vacuum tube panels of the same area. Under ALL other conditions, the vacuum tube panel will outperform flat plate panels - usually by a very significant margin. Flat plate panels perform badly during windy weather, in cold conditions, in overcast conditions etc. Some of the very best flat plate collectors can compensate for this with more advanced design, but even then, they still do not perform as well as vacuum tube panels.

How hot will the water get?

This depends on the size of the cylinder you chose, and the amount of water you use. A smaller cylinder will be heated to higher temperatures, whereas a larger cylinder will heat more water, but not to the same extent. Systems are generally designed to heat water to 65C or so, although during the winter, it may be necessary to 'top-up' the heat on less sunny days. Large arrays, running high temperature solar antifreeze at high pressures can be designed to achieve temperatures of 170C or more!

Where do these need placing and at what angle?

Panels should be sited on a south facing wall or roof. In fact, anywhere between South-West and South East will give good results. See Efficiency Chart.

If you are limited to an East-West facing system, then you will need two panels to provide the same amount of hot water as a single south-facing roof slope. The most frequent solution to this problem is normally to mount one panel on the east slope and a second panel on the west slope. A special controller is available for East/West facing installations.