Under the skin of underfloor heating

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Our focus over the last week or so has been getting the biomass boiler up and running, with help from local ecological heating suppliers A Greener Alternative. The Baufritz team have been working on getting the floors ready for the liquid screed pour. The boiler is now providing hot water in the underfloor heating so the liquid screed can dry out and form a solid thermal mass. In the YouTube clip, Joe talks to Amy about the three layers of insulation and waterproof membrane laid on top of the vast network of underfloor heating pipes in preparation for the screed. Any small hole accidentally pierced in the membrane could have disastrous effects!

The underfloor heating is powered by our new boiler run on sustainable pellets from Verdo Renewables, manufacturers of Grade 1 premium quality 6mm wood pellets with a calorific value of 4,800KWhr/tonne. Combined with solar gain from the large picture windows overlooking beautiful Lewes, the thermal mass floor becomes a large ‘slow’ radiator which ensures the room stays warmer for longer. This avoids the need for costly and energy-inefficient heating spikes if the temperature outside drops.

We’re pretty confident this system will do wonders to keep our carbon emissions low and energy bills a fraction of the cost compared to conventional radiators for space heating. In fact, Stewart Boyle, energy expert and senior associate for South East Wood Fuels, cited the Sky House Sussex heating system as a case study in his talk on ‘The RHI and bio-energy for heating’ at The Eco Technology Show in Brighton yesterday. Stewart was instrumental in helping us fathom out the complexities surrounding choosing a low carbon heating solution, so it’s good to know we are now an example worth emulating. We’d love to hear from you if you heat your house this way too.


Greening our garden with a solar installation

It’s flaming June (supposedly) and our ‘solar garden’ is now hooked up to the grid and generating green energy. This is something to celebrate today, particularly as it happens to be ‘Sussex Day‘. We have 32 PV panels ground-mounted in the front garden at Sky House Sussex…but why on earth there, you may ask? Isn’t our brand new roof a perfectly good location for the solar panels?

Well no, actually. We’re aiming to build one of Lewes’ first carbon neutral homes that produces, with solar PV, all or most of the electricity used in the house. Our objective for the solar panels is to match the energy they yielded in their original position on the roof of the old bungalow, now demolished. This is necessary to maintain our Feed In Tariff (the payback scheme which helps finance the purchase of solar panels) but more importantly it will help us reach our lifetime zero carbon target. On the bungalow roof they faced southwest and generated 8kW of electricity, or 96% of their capacity. A rooftop location on the new house, however, would mean a far less favourable energy yield; the roof is mono pitch at 7 degrees sloping towards north east and the back of the property, so away from the sun. Relatively high trees on the east/southeast sides of the house would cast shade to drastically reduce the efficiency of the solar panels.

Initially the local planners had concerns about the visibility and reflectiveness of our ‘solar garden’ proposal. So we consider it quite a coup that we managed to design an installation (well done, Joe and Vlad) which met with planning approval, has minimal visual impact and yet maximises energy generation. Everyone’s a winner! The panels now face 10 degrees south east, tilted up 10 degrees to optimise energy yield of 95% capacity, erected on metal frames but without standing too high on the ground. In fact, the new position of the panels is even lower than their original position on the bungalow, without compromising the high energy yield. Let’s hope sunny Sussex lives up to its name this summer and in years to come. Renewable energy has never looked so good!

If you’re interested in becoming a greener household, discover how renewable energy can work for you , find out how to buy solar panels and visit Solar Panels UK  for price comparisons and news on solar power.


A timber frame home for our wood pellet biomass boiler

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Our project manager Joe Eriksson and his team are working fast this week to complete the construction of our new garage which includes a storage area for our new biomass boiler, arriving on Monday. Joe’s Scandinavian house-building expertise means Bertha (the biomass boiler) will be housed in a fine timber frame building to the left of the main house. Despite our project’s huge emphasis on sustainability, it’s not possible to build the garage in a totally ‘green’ way: the structure obviously needs steel beams to maintain rigidity. The dimensions of the garage have been calculated to provide enough space for the biomass boiler, wood pellet storage plus two cars.

Yesterday we took a sneak peek at our new boiler when we visited A Greener Alternative, our local ecological heating supplier in Sheffield Park. We decided on an Austrian designed BioWIN2 Windhager, chosen for its proven reliability, ease of cleaning and minimal space requirements compared to other makes on the market such as Froling and KWB. Windhager also have an office in the UK so at least we won’t have to polish off our German to request any spare parts. This company has been designing heat equipment for nearly 90 years so we trust they know a thing or two about low carbon heating solutions. If Windhager biomass is good enough for The National Trust, we feel confident we’ve made a sound choice for carbon neutrality by installing one at Sky House Sussex.

Bertha’s vital statistics are:

  • requires less than 1.5 square metres space
  • 15kW max. output
  • 94% efficiency at nominal load
  • 280kg total weight including integral hopper (feeding mechanism)
  • Low maintenance: low pellet consumption, self-cleaning, large ash box needing infrequent emptying,  servicing every 2 years.
  • offers 80-90% reduction in CO2 emissions compared to oil heating

Nicki Myers at A Greener Alternative told us that their biomass clients range from individuals wanting to replace an old woodburner in their living room, to larger commercial installations such as the 400kW wood pellet boiler they supplied to Colchester Zoo. A Greener Alternative have also recently installed a 60kW Windhager at Crawley Down Monastery. Perhaps getting up at 4.30am won’t seem such a hardship for the monks if there is plenty of hot water for showers…

Our choice of biomass boiler as a sustainable, renewable and efficient way to produce hot water and space heating is a key part of our strategy for reaching lifetime zero carbon at Sky House Sussex. It feels great to be preparing for its arrival next week and commissioning on Friday 13th (good luck for some, we hope). Our next challenges are, firstly, to find a supplier of sustainable wood pellets who can provide us, on a practicable basis, with the 3+ tonnes per year we anticipate using, and secondly, to find out how to take advantage of the recently launched domestic RHI payback scheme. We’ll keep you posted on our findings. If you are a biomass user, we’d love to hear your experiences.


Blowing our own trumpet in the name of low carbon buildings

Whilst the Baufritz team beaver away on the first fix of electrics and plumbing and Joe’s team are building the new garage to house our biomass boiler, we are reflecting on the amazing team achievement of building a timber frame house in five days. This YouTube film captures the anticipation and excitement we all felt on the day the house ‘arrived’ from Germany. We think the soundtrack, an excerpt from the Egmont Overture by Beethoven (another crafty German) is appropriate for the glorious, sweeping Sussex countryside in which Lewes is nestled, and offers a nod to the musical delights of Glyndebourne a couple of miles down the road from us.

Meanwhile, the exceptional speed of our build and its low carbon credentials have made the news. We were featured in our local paper The Sussex Express (see below) and by Matthew Wall of BBC Online in his article Sustainable technology ‘greening’ our toxic buildings . It’s exciting and rewarding to see the amount of interest in our ‘green’ new build, as our 250+ Twitter fans indicate – thank you to all our followers. We look forward to sharing our zero carbon journey with you over the coming months.

Sussex Express news coverage May 2014

Sussex Express news coverage May 2014


On the trail of the Zero Carbon grail


We’re writing this post with some trepidation. You see, we’re going to put our necks on the line and try to define what we mean by a ‘zero carbon home’. From our own reading on the subject, a clear definition seems elusive. Those that do exist are often open to interpretation. Over the coming months we’ll be blogging about our personal strategy for trying to achieve zero carbon living in the house. This feels exciting but very exposing since we are so intent on trying to reach ‘zero carbon nirvana’.

There’s a good chance you’ll have read about other examples of low energy homes in the UK and abroad.  Perhaps they were described as ‘carbon neutral’, ‘zero-net energy’ or ‘energy-plus’ homes. The different terms for this type of home reflect the diversity of building approaches being adopted. There is little consistency around the world (differing societal and geographical influences) and so the language inevitably becomes confusing.

In the simplest terms, approximately 80% of CO2 emissions from standard buildings are produced during operation, compared to low energy/passive houses where the majority of emissions are produced during construction*. That said, as the end user, we’ve found a surprising lack of common knowledge about what a zero carbon home means in real terms. We’re not writing here as experts but as newbies learning a new ‘green’ language. What does a zero carbon home actually look and feel like?

If you want a thorough technical understanding, immerse yourself in the nitty gritty of BREEAM’s Code for Sustainable Homes (CSH) Code Level 6 which requires zero carbon emissions from a building. When we read, however, that one of the CSH criteria stipulates the correct length of washing line for your laundry, this (along with reasons of time and expense) was enough for us to decide that BREEAM was not the path we wanted to follow towards zero carbon.

Personally, we prefer a more common sense approach to sustainability.

Some time ago, we were sitting around a table with two architects, a BREEAM assessor and an energy consultant.  We believed, perhaps naively, that we would be on course to hit Code Level 6.  First up, we learned that Code 6 is scaled for larger projects. For residential builds, the bureaucracy of BREEAM can increase your build costs by up to 40%, we were told (the CSH guide is a whopping 272 pages long). Our ‘light bulb moment’ came when an architect asked us, “Can you live with a common sense code for zero carbon?”  Naturally, we replied with a robust “YES”!

‘Common Sense Code’ has stuck in this household and we aim to show you that zero carbon is entirely obtainable without the added expense.

Our zero carbon objective:

“We are aiming for a Lifetime Zero Carbon home, meaning zero carbon emissions in the use of the house and the embodied carbon in the home being offset by the energy generated over the lifespan of the building, assumed 100+ years”.

As yet, we don’t have all the facts and figures to back up these goals (construction of the house only started 3 weeks ago) but when we do, we’ll be sharing them on this blog. For the time being, our draft SAP report (Standard Assessment Procedure for energy and environmental performance of dwellings) indicates an impressive ’97’ for Predicted Energy Efficiency rating.

In terms of estimated annual CO2 emissions, these are predicted at (minus) -6.08 per square metre i.e. space heating, water heating, ventilation and internal lighting minus any CO2 emissions saved by generation from low or zero carbon technology. This is compared with 16.76 for a notional dwelling of the same size and shape.

Those figures sound like we could be on course for a zero carbon home, don’t you think? Follow our blog for more information about the construction materials and electrical/renewable technologies we are using.  We’d love to hear from you if you have experience of building or living in a zero carbon home.

*Source – Zero-carbon homes – A road map by Joanna Williams



How to build an eco house in one minute

We now have a fabulous new eco house! After almost four years of planning and preparation, it works out you can actually build an eco house in one minute. Would you believe it? This timelapse film shows the rapid construction of Sky House Sussex in under five breath-taking days. The process was every bit as exciting as you’d expect (particularly if you are an avid Grand Designs viewer like us) and thankfully without any major glitches. Even high winds and a snapped cable on the crane were not enough to deter the Baufritz team who worked smoothly and skilfully with the Brits operating the crane from TerraNova.

We were delighted to welcome the Mayor of Lewes, Councillor Ruth O’Keeffe on site on the first day of construction who commented, “It was very interesting to learn about all the ecological aspects of the construction and amazing to see the sections of the building arriving and being put in place whole using the giant crane”.

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Day 1 of construction: our sustainable new home has arrived

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The first day of construction of Sky House Sussex was an unbelievable thrill to watch. No wonder the ratings figures for Grand Designs are always so high when timber framed houses are featured. There is something endlessly fascinating about seeing part of your new house suspended high in the air dangling from a massive 40 tonne crane. Years of planning and we finally get to witness the realisation of our dream…it’s heart-racing stuff. We were blessed with perfect May weather too: a cloudless blue sky and sunshine must surely be a good omen.

The consignment of 1 x  timber framed sustainable eco house for Client Burgess had left the Baufritz factory in southern Germany on Bank Holiday Monday and crossed the Channel via the Eurotunnel: Achtung! wide load. From Dover it headed to the designated transhipping site, an old cement works site in Halland near Lewes. Here the container was opened up and one smaller lorry delivered the packs to site, one at a time. You can see from the pictures the breathtaking speed at which the ground floor was erected – we were given the keys to the front door on Day One as it was going to be locked up that night.

The Baufritz team worked with cool, calm, quiet efficiency – reassuringly we knew we were watching skillful pros at work. Although we’ve shipped a house from the continent to the UK, manufacture time in Germany was just three days and within four days of on-site construction we will have a two-storey house structure with roof (weather permitting). This short timescale affords huge benefits: the low energy, efficient construction process is delivering a “carbon negative” house with an average carbon balance of minus 50 tonnes upon delivery: more CO2 is locked away than is emitted during its manufacture, transportation and construction. Not to mention that the factory prefabrication has meant low noise levels and clean construction methods on site, resulting in minimal disturbance to our neighbours.

Other sustainable aspects of our new house construction include:

  • All materials are recyclable, fully biodegradable and thus sustainable: timber-only structure as well as internal fit out materials
  • Maximum energy savings from top quality triple glazed windows with highest thermal performance and no thermal-bridging
  • Minimum energy consumption as a result of 37cm thick energy-efficient timber walls
  • Excellent heat protection: Certified Cradle-to-Cradle thermal insulation using natural materials for walls, ceilings and roof. Wood off-cuts become shavings treated with soda and whey making them fire, fungus and pesticide resistant.
  • For more information about the house, please visit the ‘Sustainability’ page of this blog

We’d love to hear what you think about the construction methods and materials we’ve chosen – do drop us a line.