Though it looks quite simple the way water is heated up through solar energy source
but the mechanism to run hot water in all the weathers round the year requires much of science and instrumenting info. As lay man like me with no or minimal science background it is enough for me that my bills are reduced and is getting hot water through my taps all the daylong and best if its freezing outside. But to have such comfort even a common customer for solar heaters should know the basics about it to avoid the problems later. Problems such as:
1:Improper or wrong site selection that would not allow sufficient exposure tosunlight in day time. Remedy: Shady places or places where sunlight not even stands for 5 hours a day are the worst installation spaces.
2:In excitement of planting a system on sunny days you absolutely forget about those week long cloudy days that could make you suffer without hot water. Remedy: Addition of storage battery and reverse metering can store enough solar power for those cloudy days.
3:Whether flat solar panels or evacuated tube panels, these do have a shelf life. Their extended life is for 25 years and can get deterioted and old. Such old solar panels can result in seepage of toxic chemical as mercury and chromium in underground water. Remedy: There are organizations and companies offering recycling option of these panels and addressing safe disposal of these panels. Anticipating a recycling remedy would always save you from disposal part.
Now after anticipating such issues you are almost ready to choose the system. Solar panels are the first thing to consider and people find themselves always in a fix to decide between evacuated tube solar collector and flat plates. Moreover the value you pay is the foremost thing to consider while deciding to have one in your area.
Evacuated tubes are expensive with 20 % more as compared to flat ones .But yes the vaccum insulation and for weathers of more cloudy over cast days they are the best. These are modular and separate in pieces so it becomes quite easy to install. These come with extra support for heat dissipation.
Flat plates are though cheap in prices not much for utility in cold areas and they lack extra support for heat dissipation too. For the areas where weather is fairly sunny and warm flat plate are the best value panels.
Well whatever you choose as per your need, you got to see that SRCC certificates and warranty for technology with not less than 10 years. Remember that being well informed about such systems would always pay you in long run.