Solar water heating works efficiently even in cloudy areas. Home Power Magazine recently ran an article that gives a simple overview of solar water heating systems (well, relatively simple). In the article, they examine various popular systems that have proven themselves reliable.
Apricus makes a unique solar hot water heater which is 30-40% more efficient than flat plate solar systems. The secret to the performance is the use of cylindrical evacuated glass tubes to absorb the heat from the sun. Because the tubes are cylindrical, there is always a surface area that is perpendicular to the sun. […]
Notes from Manufacturer: The AquaStar 240FX (Natural Gas or Propane) can supply 2 major hot water outlets at the same time at a rate of up to 5 gallons per minute. Can be vented vertically or horizontally to the outside. High efficiency rating of 83% and an Energy Factor of .84. Purchase from: TanklessWater.Com