I've been reading here for a long time, this is my first post.
I thought I'd contribute something useful, last year I built my own batch solarhot water heater. I would encourage you to give this a go if you are halfways handy. The savings on my energy bills have been significant and I'm really glad I went to the effort.
I've linked my blog where I wrote a lead in article here. The main articles which go into more detail live on a content site that advertises a fair bit so I'll leave it to you whether or not to go there, the links to my more thorough posts are in the first story.