Yes. Although the heat output of the solar hot water collectors is reduced on overcast days it will still be able to provide heating. If it is a heavily clouded day or raining, then an electric boost may be required to maintain water at the required temperature. Our solar hot water systems will be automated so you don't have to worry about running out of hot water on a rainy day.

Yes. Simple retrofit valves can be used to allow solar hot water collectors to connect to your existing geyser inlet. This is actually an ideal and far cheaper way to install a solar powered geyser. Provided that your existing geyser is not very old.

Yes, in good weather the solar hot water collectors can bring water to boiling point. Generally this is not necessary and so the solar hot water system should be designed to provide a daily temperature rise of around 25-30oC (45-54oF) in the summer. Sizing a domestic system that can bring the cold water up to 60oC/141oF in a single day is not logical, because if hot water is not used for one day, the following day the solar hot water system will be boiling and dumping hot water via the temperature relief valve. This is both a waste of energy and water!

Under normal circumstances no maintenance of the hot water system is required. Due to the shape of the tubes regular rainfall and wind should keep the tubes clean. Should a tube even be broken it should be replaced. This, however, is an inexpensive and easy job. Any "handy" person can install a new tube. The solar collectors can operate with several broken tubes, however the efficiency will be reduced slightly.

When comparing peak efficiency levels it may seem that there is little difference between flat plate and evacuated tubes, in fact flat plate may actually be higher, but this is during minimal heat loss conditions. When averaged over a year evacuated tube collectors have a clear advantage. The key points are:

• Due to the cylindrical shape of the evacuated tube, the solar tubes are able to passively track the sun throughout the day. Flat plate collector only provide peak energy output at midday when the sun is perpendicular to the collector's surface.
• Air is evacuated from the solar tube to form a vacuum. This greatly reduces conductive and convective heat loss from the interior of the tube. As a result wind and cold temperatures have less effect on the efficiency of the evacuated tube collector.
• Solar collectors can often be used in subzero temperatures without the system sustaining damage. Flat plate systems often require expensive and complicated "antifreeze" systems to be installed.
• Evacuated tubes are strong, long lasting, and should one be broken, inexpensive and easy to replace. If a flat plate collector panel is damaged the whole panel must be replaced.
• Due to the high efficiency absorption of solar radiation even during overcast conditions, combined with excellent insulative properties of the solar tube, solar tube collectors can heat water all year round.
• Due to the various advantages of evacuated tube collector over flat plate collectors, a smaller collector can be used to provide the same heating performance. For example, a standard household of 4-5 people would usually require a 250-300L geyser. Depending on your location, only 22 evacuated tubes would be required to provide hot water needs.
• Flat plate solar collectors can produce similar heat output to evacuated tube collectors, but generally only during hot, sunny conditions. When averaged over an entire year, evacuated tube collector heat output per net m2 of absorber area, is between 25% to 40% greater that a flat plate collector.