Common Questions & Answers

Q. Can solar hot water heating really work in Scotland?

A. Yes, the system design is very efficient using evacuated tubes for the solar collector, this is a proven technology which has been around for more than 10 years, and is ideal cooler and more changeable climates like Scotland.

Q. How do vacuum tubes compare with flat panel collectors?

A. On hot summer day there will be very little difference on the amount of heat produced for the same surface area. The vacuum tubes come into there own in all other conditions, like on cloudy day, or in the winter when outside temperatures are low, they will out perform the flat panel collectors. The heat losses from the vacuum tube panel are much lower because water is only in manifold, unlike the flat panel collector where the water flows through the panel.

Q. How much hot water can I expect?

A. Over a year the system should provide 60% of your hot water requirements.

Q. Is there a risk of freezing?

A. The system is filled an antifreeze mix which will provide protection down to -25 ºC.

Q. How tough are the vacuum tubes?

A. The vacuum tubes are very tough, made from borosilicate glass, also known as pyrex. These tubes are designed to withstand hailstones up to 35mm.

Q. Where can the solar panels be installed?

A. They are best sited on south facing roof, at angle of 15º or above, most roofs are about 30º angle. They will work anywhere between south and west still giving good heat output. If your roof is west and east facing then a panel can fixed to the west and east facing roof and controller with east/west option used.

Q. Is better to replace hot water cylinder?

A. Yes, a 2 coil solar cylinder will work better and be more efficient, as the solar coil has a larger surface area and is at the bottom of the cylinder. If you have vented cylinder with cold water storage, the incoming water to the cylinder is about 10ºC in the winter and 20ºC in the summer. The solar panel will start heating up the bottom of cylinder once the panel temperature is 6ºC above the temperature at the bottom of the cylinder.

Q. What type of solar cylinder?

A. There is choice of 3 types, vented with cold water storage above cylinder or in attic, and mains pressure hot water from unvented and vented (thermal store) from secondary coil. The difference is down to cost and whether your mains pressure is adequate and if you prefer mains pressure hot water.

Q. What temperature of hot water can I expect?

A. The system is designed for a temperature of about 65 ºC in the summer, but its dependant on the cylinder size verses the solar panel size. If a smaller cylinder then design size is used, it will produce a higher temperature, a bigger cylinder than design size will produce a lower temperature. Even in the winter on a sunny day it can preheat the water by 30 ºC.

Q. How can I tell if the solar system is working?

A. The solar controller displays a flashing symbol for the water pump when the water is being pumped around the system. You can display temperatures of solar collector, hot water and kW produced.

Q. What maintenance is required?

A. Very little maintenance is required, occasional checking the solar system water pressure, same as sealed systems for central heating. The tubes do not require cleaning, as any dirt on the tubes is washed off when it rains.

Q. I have combi boiler, can solar hot water heating be installed?

A. Depends on model of combi, some newer combi boilers are already solar compatible allowing hot water to pass through without firing up and firing up if water temperature is below 55ºC. For other combi boilers, some different solutions are: convert the boiler to system boiler and have stored hot water only, use thermal store or unvented cylinder with thermostatic mixing valve, replace combi with high efficiency condensing boiler and use store hot water.

[ BACK TO TOP ]