Heating the house without warming the planet

We hope that we won’t have to heat the Westacre house at all. And if we do, the thermal solar panels should cover most of it.

If all our insulation efforts, and the money we spent on high quality triple glazed windows, work out as intended, our house should be snug throughout the year.

A 16 cm layer of insulation on the outside of the walls, combined with the air tightness we hope to achieve, should cut out any draughts. That should keep all the warmth we generate from cooking, running appliances, and our body heat, inside the house.

Air tightness is great for that, but of course we also need to breathe. We will have to pump fresh air into the house and duct it to different rooms. The air will go through a heat exchanger, sharing the heat of the stale air going out with the cold air coming in. Our heat loss overall should be minimal.woodstack

It’s no guarantee that we’ll be warm enough though. We’ll need to live in the completely insulated house over one winter to work out exactly how much heating is needed.

If we do need to heat the living areas, we intend to do that with hot water from thermal solar panels on the roof. The hot water they generate will go into a heat store, basically a big insulated tank of water that can be pumped around the house when needed. We intend to use it for washing and bathing. And for any heating we need on cold days.

The tricky part, of course, is that when you need heating most, on cold winter days, the solar hot water panels are going to be the least effective. If we find ourselves feeling cold in winter, we’ll use a wood burning stove as extra heating. A stove with a back boiler will also be able to generate more hot water if we need it.

Consequently, we’re building a bit of redundancy into the house. We’re putting pipes for under floor heating into the concrete layer of our downstairs floor in case we need them. We’ll wait and see if we need a wood stove with a back boiler, and how big it needs to be.

And we’re keeping our eye out for free wood, like the dead alder trees Alex’s dad had removed from behind his house. It took us a fair while to chop them up, transport our share to Westacre, and pile them under the leylandii where they will have to season for a couple of years. We are also growing hazel trees for coppicing in parts of the garden.

Wood is a carbon neutral fuel, but if everyone started heating their uninsulated draughty houses with wood, there would soon be a shortage of trees. Insulating the building as much as possible first ensures that we don’t use more than our fair share of trees.

Worth, value, and the cycle of gift giving

Over the last couple of weeks, I have been considering some new ideas for the Westacre Spiritual Centre. I am developing a programme of one-to-one mentoring for younger or less experienced Pagans. The question, as always, is how to charge for that. The whole issue has brought up a host of other thoughts about my […]

Insulating under the floor

Insulation is the main ingredient in our efforts to minimise Westacre’s carbon footprint. If we can retain as much heat as possible within the house, we may not have to heat it at all. To get there, we need to insulate thoroughly, including above the ceilings in the loft and below the concrete floor.

We are adding a substantial layer of concrete to the floors downstairs. They will function as a heat store, helping to keep the house warm and the temperature even.


Of course, if you want your concrete floor to be a heat store, it needs to be insulated from the actual cold and damp earth. Consequently, we have to install a lasagne of insulation layers under the floor. When all of it is done, it will look something like this:

The starting layer is the site concrete. In the part of the house we are working on, that’s nearly 90 years old now, and very lumpy. We had to even it out with sand to protect the first layer of our lasagne.

First of all, we put down sturdy black plastic as a damp proof layer. It is glued to the actual damp proof course of the house. And of course, it’s important this is not perforated anywhere. Hence the sand.underfloor1

On top of the plastic are three layers of polystyrene, to a total of about 22cm. All of that is edged with thin Celotex insulation boards going a bit higher up the walls. It’s all been foamed in at the edges to keep everything in place.

Next comes another layer of clear plastic for protection.

The concrete layer is next. But we’re adding a few more features to that.

A lot of electrical and date wiring will run through conduits under the concrete. And we are putting in the pipes for an underfloor heating system. As we don’t know how much heating we’re going to need, we intend to be prepared for everything.underfloor3

So, on top of the insulation, raised on some bricks, we will be placing a mesh of concrete reinforcement bar (rebar). The underfloor heating pipes are coiled on top of that.

And then we order in the cement lorry. When that day comes, I’ll be sure to get the video camera out. We are hoping for a concrete layer of about 15cm.

The whole thing is levelled off with screed, and eventually we’ll tile on top.

We are investing in staying warm for the long run. When the renovation is finished, we hope to only have to use the underfloor heating on very cold days. It will be fuelled by solar hot water panels, backed up by a back boiler on our wood stove. We’ll only know how well that has worked when the whole project is finished and we’re living in it.

In love with life

Every so often, I fall in love with life again. Suddenly, everything feels fresh and new, and I get excited just taking it all in. This is one of those times. I don’t know what it is. The time of year is helping, with Westacre’s drifts of snowdrops promising Spring. But this could happen just as [...]

Hatching a new life

Something significant appears to be happening. It has kind of come out of nowhere. Or perhaps I should have been expecting it. A lot of strands in my life are coming together and it feels as though something new is about to be born. Something that hasn’t quite ever been before. It dawned on me, for [...]

Insulating the loft

This last week or so, Alex has started constructing a floor in the loft. When it is finished, we will be insulated from the cold by a lasagne of many layers.

The ceiling will be made of ordinary plasterboard. We’re not just attaching it to the bottom of the joists, though. We’re raising the ceiling a little by putting the plasterboard half way up the joists.

Above the plasterboard, we’re having a cosy layer of non-mineral insulation wool.

Next is the OSB floor that is being installed right now. It is tongue-and-grooved on four sides, so it fits together tightly. Any gaps are filled with the black sticky stuff that we’re also using on the external wall inslation.

On top of the OSB we’ll be putting 15 cm of Celotex insulation foam. Around the edges, where the roof comes down low, there will be woollen insulation instead.

And finally, on top of the Celotex, we’re putting a layer of thin plywood. We will need to be able to walk around in the loft, as it will be the nerve centre of our house, with lots of pipes, cables and ducts leading off in all directions.

We are doing this work now, so that we have something more than just plaster board, floor boards and roof tiles separating us from the frosty night air. It should instantly give us some more warmth in our temporary flat.

Who does the Grail serve? An Imbolc healing

I feel immensely grateful and privileged to be part of a very special spiritual community. We are a pretty random and ever-evolving group of Druids who camp together four times a year, at the major festivals. Every camp is different, but each one offers challenges and opportunities for healing. This time, I went to camp with [...]

Can we power electric cars?

There were 240.0 billion car miles driven in the UK in 2013. That’s 386.2 billion car kilometres. [source]

If electric motoring costs 0.34 kWh per kilometre (from your 4 year old link), then that requires (386.2 × 0.34 =) 131.3 TWh of extra electrical energy.

Total electricity generation was 359 TWh in 2013. [source]

So switching to all electric cars would required the UK to increase electricity generation by 37%, according to the article you linked. If we all drove Teslas, which achieve 0.24 kWh/km, then generation would only need to increase by 26%.

The place beyond emotion

Over the years, I have come to accept that my spiritual life goes on a break when I’m visiting my mum in Belgium. Even when I manage to carve out some time for meditation, it never really works there, for whatever reason. So it’s good to get back home and pick up the thread again. For [...]