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      

Wooden box 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


Checking that the aluminium absorber plate for our DIY panel fits with 4mm gap around it so it can expand in the heat.

A sheet of aluminium foil sits on top of the insulation and below the absorber plate. This reflects heat back to the aluminium absorber plate.

Scratching the aluminium absorber plate, marking and drilling


We scuffed up the aluminium absorber plate with a wire brush so the paint will ad-hears better

Drilled holes in the panel’s absorber plate to fix the copper heat exchanger. This heat exchanger transfers the solar energy in the for of heat to the water that flows through it.

Solar heat exchanger components


Laying out and checking the copper heate exchanger (snake) parts before for cleaning and soldering. This can also be made by bending malleable copper pipe. A small round tin is helpfull to form the curves. We used pre-fabricated corners and short sections of conecter pipe. I like soldering. This method takes a lot longer and you need to be quite good at soldering.

Clean the pipe ends thoroughly with wire wool and use flux before soldering the joints. It’s difficult to solderr dirty joints and they are more likely to fail.

Soldering up then testing it


Our finished copper snake after competing the soldering. Ready for a clean with a wire brush and then pressure testing.

I sealed one end of the snake (middle picture) ready for testing our DIY Solar panel

To makes sure it’s fine under pressure and especially before fitting the glass and painting it I attached mains water pressure to test for leaks and left it for a couple of hours. Also manhandled it bent it a little occasionally to stress it. Much better to find any weak joints / problems now before the glazing and painting.

Fitting the heat exchanger and  glazing the solar panel

   DIY Solar panel

In first picture you can see me fitting the glazing strips around the inside of the box that support the glass or perspex sheet.

Then cutting the previously sealed end so it will fit through the hole in the box

Screwing the snake in the box after all the 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 then water from a bucket through it or about an hour. It performed very well and easily heated the bucket of water to 60-65 degrees.

It’s probably cehaper and quicker to buy a panel. But making your own DIY Solar panels is a great way to learn how it works.