a short video showing the small solar water heater i designed a couple of days ago. it consists of 136 feet of 1/2″ black tubing. internal diameter is actually 3/5″ (cost approx $10.00), 4 connector pieces (to connect the various pieces together and to connect it to the house (cost approx. $5.00)), and finally the ‘y connector’ so i could have the garden hose hooked up at the same time (cost approx $5.00). all purchased from home depot. total cost was approx. $20.00. all i did was coil 100 feet of the hose and attach it to a piece of plywood. after 30 minutes of sun the water temperature is about 130-133 degrees and after 60 to 90 minutes it can reach 150 degrees. the tubing can hold about 2 gallons of water at a time. if you drain and refill several times throughout the day you could easity get 10-15 gallons of hot water a day. of note: they call the tubing 1/2″ but the actual internal diameter of the tubing is 3/5″ (.6 inches). 100 feet of tubing holds 1.47 gallons and 136 feet of tubing holds approx. 2 gallons. home depot sells a 500 foot roll for about $35.00. that would hold 7.36 gallons of water.