Dood shemesh (solar water heaters) - Time for a rethink

This is comment I left on Treehugger for this story

I have been living in Jeruselem for the past few years and the 'dood shemesh' ( I prefer to spell it that way ) is an integral part of the skyline , very jarring at times but let's leave the aesthetics for the time being . The dood works wonderfully well in the summer , we have hot water for the bath , for cleaning washing , infact we can even flush with hot water if we want . In winters, when you really need , the dood falls short . True we don't have harsh winters and even on a cold day you can have lukewarm water in the afternoon but very often the dood is located a couple of floors away from it is used , so you waste quite a bit of water and secondly invariably the electrical heating element is located in the tank on the roof which is exposed to the elements and inspite of being insulated is losing heat constantly . I don't have figures but I am told that the dood actually is less economical . If one factors in the cost of the collectors and the boiler and the fact that they need to be changed every few years , the dood is no longer that economical or green .

This needs to be researched a bit more before we let the axe fall on the dood . A very simple way to save the water that you need to let go waste is to have an additional boiler within the house which is fed by the tank on the top . That way if it is cold outside the tank inside the house is not effected by the cold and you don't waste energy heating water that is quite exposed .