DIY Solar hot water panel

This is our home made / diy solar hot water panel. Apologies for the small photos.

Wooden frame/box for the DIY solar panel

DIY Solar panel      

The wooden box we made to house the heat exchanger and piping before painting/treating it with wood preserve

It’s important to protect the box well because it’s got to last a long time so make sure you really slap on may coats of paint!

Note the centre absorber plate supports (I’m painting them)

Corner supports & insulation


Here you can see the the small triangles of wood in each corner to support the corners of the aluminium plate

30mm Rockwool type insulation was placed behind the aluminium plate to insulate it. This makes sure we don’t loose too much heat out the back of our DIY Solar panel

Solar absorber plate and foil reflector


Here we are checking that the aluminium absorber plate for our DIY panel fits with 4mm gap for heat expansion.

The aluminium foil sits on top of the insulation and below the absorber plate. It reflects heat back to the aluminium absorber plate which sits on top of it.

Scratching the aluminium absorber, marking and drilling


We scratched the aluminium absorber plate with a wire brush so the paint ad-hears better to it

Holes were drilled into the panel’s absorber plate to fix the copper heat exchanger. The heat exchanger transfers the solar energy/ heat to the water that flows through it.

Solar heat exchanger components


Laying out and checking the copper snake parts ready for cleaning and soldering. You can also make this part by bending malleable copper pipe. Use a small round tin to help form the corners. You could also used pre-bent corners and short sections of pipe. This takes much longer and you need to be quite good at soldering.

Either method makes a good heat exchanger

Make sure you clean the pipe ends thoroughly with wire wool and use flux when soldering the joints. The cleaner they are the better the joint will be and less likely it is to fail

Solder the test it


Our finished copper solar heat exchanger after all the soldering. Now ready for a clean with a wire brush and pressure testing.

Seal one end ready for testing the solar panel

Just to makes sure it’s water tight under pressure especially before fitting the glass and painting it attach mains water pressure and test for leaks for a couple of hours. Give it a bit of a bash and bend occasionally to stress it. If there are any weak joints it’s better to find them now than later.

Fitting and  glazing 

   DIY Solar panel

Fitting the glazing strips around the inside of the wooden box to support the glass or perspex sheet.

Cutting the sealed end so it will fit through the hole in the box

Fitting the snake in the box after all the brackets / pipe clips have been put in place

Before final assembly paint the absorber plate with some mat black metal paint


We attached a small water pump to this panel the circulated water in a bucket for about an hour. It performed very well and easily heated the bucket of water.