A direct system produces the highest operating performance, because there is no nighttime heat losses from hot water stored on the roof as in a passive system nor is any efficiency lost through a heat exchange process as in a closed loop system.
Potable water from the hot water storage tank is circulated directly through the collector.
The result is water heated between 140 and 160 degrees, as a result, by turning on the faucet, you are mixing (adding) more cold water with less hot water sustaining more free solar heated water awaiting use. There is also an optional anti scald valve (mixing valve), which can prevent injury when turning on just the hot water.
It makes economic sense to think beyond the initial purchase price and consider lifetime energy costs, or how much you will spend on energy to use the appliance over its lifetime. It has been proven that solar hot water systems offered the largest potential savings, with solar hot water owners saving as much as 85% annually on their utility bills compared to the cost of electric or propane water heating.
Our customers can verify their outcome for you upon request.
If you are building a new home or refinancing your present home to do a major renovation, the economics are even more attractive.