• Ø 20 mm PVC pipe (25 m long), 
  • 90mm PVC elbow connectors (4 units) 
  • 20mm PVC T-connectors (20 units)
  • glue for PVC 250 gr (1 unit)
  • matte black paint
  • roller
  • sandpaper 
  • self-amalgamating tape
  • 100-litre plastic container 
  • standard hose (50 m long)
  • 2-litre plastic bottles (40 units) 
  • milk / juice cartons (50 units) 
  • wooden strips
  • screws
  • toolbox 
  • Ø 100 mm PVC pipe or similar (cylindrical) (0.5 m long)


This craft will allow you to heat water for domestic use, thanks to solar radiation, applying the thermosyphon principle, like a conventional solar water heater. How can you do it?

  1. Make sure the bottles are clean and have no surface damage.
  2. Use the Ø 100 mm PVC tube as a mold to cut the bottom part of all the bottles. Try to cut them so that one bottle can be inserted into another.
  3. Cut the Ø 20 mm PVC pipe into pieces of 10x1m (total of 10 pieces) and 20×8.5cm (a total of 18 pieces)
  4. Paint in black the cardboard or plastic sheet and also the 10x1m Ø 20 mm PVC tube.
  5. Tuck the bottles into the tube, so that one goes into another, to fully cover the black PVC tube. 
  6. Join the segments with the 20 mm PVC T-connectors using PVC glue 250gr. The upper part will channel the hot water while the lower part will receive the cold water.
  7. Link 2 black tubes to a 90 degree angle with the PVC elbows and join one part with the bottom of the T-panel, and the other side with the top, so that the cold water enters from the bottom and comes out hot to the end of the system. 
Tank installation: 
  1. Place the water tank in a structure 30cm higher than the highest point of the solar panel. Try to protect the tank from direct sunlight, by placing in a shady area or using a cover. 
  2. Punch 5 holes in the tank, placed as follows: 
    1. Two at the top with a tap. Each one will be placed in different parts.
    2. One in the middle of the tank. This will introduce hot water into the tank.
    3. One at the bottom. This one will conduct the cold water
    4. One in the middle of the tank, much higher than hole b. 
  3. Connect the hot water pipe and the cold water pipe to the tank. The cold water pipe must be inserted into the tank.
  4. Connect the tap and level tap through a valve consisting of a plastic bottle linked to the outlet tap. Connect the shower or inlet plumbing to the tank.
Structure installation:
  1. Collect or buy small wooden or metal beams about 1m long.
  2. Measure the final dimensions of the panel (the size should be around 1m x 1.20m) and cut the wooden strips.
  3. Join the beams in a triangular structure with an angle from the diagonal, depending on the location in your home.
  4. Make different holes with a drill, so that they approximately fit the pipe position. Put a strip into the hole and prepare four packing rings and nuts.
  5. Fix the structure to the ground or other surface with screws. 

All this effort is worthwhile! You will save money in a few months!