The (hi tech) wood burning range

It is always surprising how serendipity can prod you into realizing an idea that you didn't quite manage to convince others to follow or - maybe more truthfully - that you didn't dare pushing enough. Some concepts seem too radical and yet they keep on coming back to your mind until such time as an external parameter convinces everyone that it is the way forward, usually for entirely different reasons.

This has just happened to me again on the farm project.

My gut feel right from the start was to heat the house and its water purely with locally found renewable sources: wood and sun. It probably was due to the childhood memory of the farm of my paternal grand parents who lived without central heating. A large fire place and a stove - both running with wood - were the only space heating systems in the whole building. Only one room of the house was really warm - the living room. In the winter, hot water bottles were used to warm the beds before going to bed. I loved looking after the fire. Although it surely was cold, I have stronger memories of heat that any other place since. The contrast between warm and cold re-enforce the perception of both and create an experience which might not always be comfortable but that makes you feel alive and fully in connection with the seasons.

There was also the incentive to be able to be self-sufficient as the property is large enough for letting a third grow as forest and indeed ash and oak - two of the best woods for burning - have self-seeded abundantly.



I started with a belt and braces approach. My idea was to use a wood burning boiler connected to a large heat store. Even in the coldest weather, you only need to run it once every day or two to produce sufficient heat for space and water. Solar panels can also be connected to the heat store to heat the water in the summer. On paper this solution is perfect but once costed it appeared that it was simply not a viable option. The cost of the whole system, including under floor heating is about 20K euros. I was also not completely happy with the lack of presence of the heating system; the very large boiler has to be in a separate room and you have no perception of the fire.



This option was replaced, following the guidance of a plumber specialising in green systems, by an air source heat pump with no solar panels. This was in no way particularly attractive as it is a slightly noisy machine which removes the process of heating from view and is entirely automatic. Yet it did seem to have the clear benefit of being a simpler and cheaper system with a substantial energy saving (you get 4.5 times the energy you put in on average in that part of France with a mild climate). That was until you realized that it still costed 15K euros for a complete system with under floor heating (and no solar panels). So again, we couldn't afford it.



Extreme situations make you creative and more flexible. As the big part of the cost was the under floor heating, we decided that we will give up on a high tech high environmental solution. We retreated in removing all central heating and using wood burning stoves in the living spaces with high performance electric radiant heaters in bedrooms and shower rooms. Our idea was that the heat recovery ventilation system will spread some of the heat from the wood and the electrical radiators will only be used as a fail safe system in the rare occasions when the weather is very cold. Considering the excellent level of insulation we were introducing, there shouldn't be the need for much heating anyway.


It is amazing what tax systems can do to a project. Although it is usually a limit, it can sometime be the occasion of a radical answer to a problem. Part of our budgetary difficulty was that following early advice, we had set our budget around a reduced rate of VAT that applies in France on renovations. Once we looked into it, it appeared that we were just outside of that case and will have to pay an extra 14% of tax. After spending days trying to find ways of avoiding this I eventually came up with the solution: we will not have any radiators at all. The regulation will allow us to use the low VAT rate if we could end up with a total space heating system (including fire places and stoves) that was no more than 2 thirds new.

So out went the electric radiators and in came a wood burning range - the Ironheart from Esse. This stove not only heats the room it is in but also hot water with a back boiler that is connected to the hot water tank and a single radiator which is a cooling mechanism to avoid overheating. The later will be placed in the main shower room. It also has an oven and two rings to cook with. On top of it, it is very efficient at 81.8% due to its advanced clean burn technology.

What really convinced me is that you can sea the fire through a fairly large window. Burning wood is not only a technical solution but also an emotional one. You are warmed by seeing the light of the fire and smelling the wood in the room.

The Ironheart is a mutitasking object; an old idea improved with the most advanced technology. It burns the wood incredibly efficiently, cooks, heats the space, heats the water, and at the same time gives you the spectacle of the fire that warms you psychologically.

It will be installed in the kitchen in one of the existing two fireplaces. The other will be left as is forming the third old part of the space heating to comply with the low VAT rate. This has the consequence that we now can afford the thermal solar panels!

It is not without irony that we end up full circle and with a simpler and way cheaper system. The house will now function like a Passiv Haus but even better as the source of heat is only wood and sun. The technology is simplified and more fundamentally the heating forms part of the way of life, it becomes a joy central to the domestic space.

You will wake up in the morning in a coldish house, go down and light the fire in the kitchen and within an hour or two the whole house will be warm again. You can boil a kettle for tea, roast the lunch in the oven, have a shower or simply watch the fire with simply burning wood that grew a short walk away...

Of course it requires some effort from you and it will be a bit cold when the first person gets up but it seems a short price to pay to have a simple system that is unlikely to break and cheaper. I would even argue that it is in that very small effort that the reduction in energy consumption lies: it forces you each day to decide whether you really need all that heat. Heat is not a given, it is something you have to work at. Instead of wasting heat that you don't enjoy, you make heat that you cherish. Your body adapts to a broader range of temperature and you feel deeply connected to the rhythm of the seasons. It is not an impersonal heat but a soulfull one. And lets face it, everyone loves looking after a fire...

What I am the most interested in this story is how serendipity and pragmatism has guided me from a heavy technology and costly solution to a more staightforward and cheaper one. The other aspect worth pointing out is how the solution is a traditional one that has been radically changed through the latest technology in wood burning, heat resistant glass, insulation and ventilation. The result is something that works very similarly to the old house with a range (which were indeed cold) but with heightened comfort and reduced wood consumption.

This shows that often the best solutions grow from the development of a tradition with high technology as opposed to the invention of something completely new.