Vacuum tube collectors are isolated from environment by vacuum which allows these systems to be very productive in the coldest of winter conditions. Flat plate collectors are open to atmosphere, and climate has direct effect on productivity on these collectors. However, in summertime when ambient temperature is high the flat plates will use that atmospheric energy to boost efficiency. The result is that flat plate collectors are better for customers looking for system in warm sub-tropical climates or summer only production, and vacuum tubes are better for customers looking for production in cold climates or winter production.