Monday, January 21, 2013

Fireplace water heating system (Part 1)

Fireplace water heating system (Part 1)
A couple of years ago, we installed a log fireplace at home, a 13KW box from Rotin fires of Zabbar. I'll try to find and post the brand and specification details of the firebox. We light it up only for 3-4 months a year, starting in November/December till March.
These are obviously the worst months for heating water from the sun simply because the days are the shortest and temperatures are the lowest. In fact, during this period we have a deficit of hot water from our water solar heater and we need to boost it up with the electric heating element.
This is why I decided to explore the possibility of heating my solar water tank using escaped heat from the fireplace.
The pictures below show what I did to capture heat from the fireplace.

The above pictures are a 0.5 metre section of the chimney with a 15 metre half inch copper pipe wound around it. The idea is to capture heat escaping from the chimney pipe and getting it absorbed in the liquid circulating in the copper pipe which will eventually heat up the hot water tank. 


Getting the copper pipe around the chimney pipe proved to be a tough job; in fact I needed help from my two little boys :)

Once the copper pipe was properly wound and secured to the chimney pipe, I used a blanket to insulate the copper pipe from the outside air, thus decreasing heat losses.

The below pictures show the final result. The blanket has been further covered with fibre-glass to further insulate and protect against the elements.

I'll be posting another article with all the details of the plumbing and circulating pump once I have everything installed and working.


  1. I would be interested to hear how it goes.
    I am thinking about doing something similar for my fire, but using the water for heating a downstairs room instead of the hot water system(which is solar)
    Would it preserve more heat if there was more insulation around the heat exchanger, to further minimise losses?
    Good luck with it.

    1. Hi Ian

      Thanks for your feedback. I'll be posting my review on how it worked but it will happen next year since I have stopped using the fireplace some time ago... the temperature is already 20 Degrees Celsius here in Malta.
      Yes, maybe more insulation would help however my biggest concern is that the heat exchange surface area is small and not enough heat would get transferred.

  2. I admire your work and I think you are very talented and creative. Thank you so much for sharing so many beautiful things!

    Heating & Cooling Systems Mississauga

  3. Excellent .. Amazing .. I’ll bookmark your blog and take the feeds also…I’m happy to find so many useful info here in the post, we need work out more techniques in this regard, thanks for sharing.Mechanical Contractor

  4. Can you buy this pipes already with heating copper pipe and insulation?