Flat plate panels are used mainly in conservation areas as as the authorities see them as more pleasing to the eye and blend in to the surroundings more.

The problem being is that in many cases they are less efficient due to a number of factors, the main factor being solar deflection if the sun is not directly over the top.

Based on like for like pricing vacuum tubes are usually more efficient, the average efficiency of flat plate collectors is about 80% compared to 90 - 94 % with the vacuum tube.

Vacuum tubes do have many benefits, we have allready covered the better efficiency.

The other aspect is installation, the framework and heat exchanger can be assembled on the roof so less people and equipment is required. You do not need to add the vacuum tubes until the rest of the system is fitted and commissioned.

Once you are happy all is working well you can the insert the vacuum tubes into the heat exchange. This installation method ensures the heat is only generated when the system is ready, exposing the solar collectors early could cause overheating.