Would you like to be able to walk and cycle more easily and safely? To breathe clean air and enjoy a reliable, affordable public transport system?
Transforming our transport system from one that is highly polluting and heavily reliant on fossil fuels into one that is clean, green, reliable and affordable is a challenge, but it can be done. Here is a selection of ideas on how we can create a better transport system that’s not only healthier for us all, but is compatible with a zero carbon future. Continue reading “Creating a zero carbon transport system”
Can you imagine a future where our diets are healthier, more varied and sustainable?
Reforming our high carbon, low quality food system will be a complex challenge, but it is possible. Here are a selection of ideas on how we can create a better food system that’s not only healthier for us all, but is compatible with a zero carbon future. Continue reading “A food system fit for a zero carbon future”
CAT’s Architecture Professional Diploma students celebrate the end of their studies with a private view of their work and a party at CAT on 20th January.
This unique event invites industry VIPs, students, local people and friends of CAT to view the final projects of these up-and-coming architects after 18 months of intensive study. Transforming study rooms into exhibition spaces their inspirational designs and models will be available to view with the students themselves on-hand to talk guests through their visions. This will be a unique insight into the ideas of the architects of our future. Continue reading “Celebrate with CAT’s architects of the future”
Want to refurbish your home in a sustainable way? With over 25 years’ experience, including as tutor on CAT’s Eco Refurbishment course, Nick Parsons has some great advice – here are his top tips.
1. Make it air-tight.
Stop unintentional ventilation (this involves designating an air-tightness layer – and sticking to it!) and design in sufficient intentional ventilation. For a whole-house retrofit this will almost certainly be whole-house mechanical ventilation with heat recovery (MVHR), but for incremental retrofits, or those with less stringent air-tightness targets, passive ventilation may suffice.
2. Insulate, insulate, insulate!
Don’t automatically believe that Building Regulations standards of insulation are enough. They aren’t bad, but in many cases we should be aiming for far better. If you have the space – and the money – Passive House levels of insulation (U values of 0.15W/m2K or less) and air-tightness (less than one air change per hour for the refurbishment EnerPHit standard) can dramatically reduce your heating requirements and massively improve comfort.
3. Insulate externally! (Unless you can’t…)
External insulation of solid walls, if detailed properly, puts the entire building fabric inside a warm ‘tea-cosy’. But it does make your house look different.
4. Risk-manage your insulation
If you have to insulate your solid walls – or sometimes even add insulation to your cavity walls – internally, excellent detailing is critical. Insulating walls internally makes the room warmer but makes the walls themselves colder and more at risk of interstitial condensation – condensation within the new thickness of the wall, behind the insulation. This can rot joist ends and other embedded timbers, and maybe grow mould. Cold walls may also suffer from deterioration of the masonry due to frost damage.
If you insulate internally, make the whole process a documented risk management exercise – identify the risks, identify control measures and document how you will implement them. In certain circumstances, consider embedding sensors and monitoring equipment in hidden timbers so that you can know if moisture levels become critical. The expense may be off-putting, but it will be a great deal less than the remedial works if you have inadvertently shortened the life of your house by doing what you thought was the ‘right thing’.
In general the use of ‘breathable’ (water-vapour-permeable) insulants such as wood-fibre or cork may reduce risks, but very careful detailing is still required.
Greater risks exist with non-breathable insulants, but if they are installed with extreme care, the risks may be capable of being ‘managed’ and minimised. If you are installing them yourself, take advice from someone with a lot of experience. If someone else is installing them for you, are they experienced with such boards? Do they fully understand interstitial condensation and vapour control layers (VCLs)? Have they read the manufacturer’s installation instructions?
5. …and consider its environmental impact
Materials such as plastic insulation – made from crude oil – are high in embodied energy (the energy, including transport, used to get the product from raw material to the merchant’s shelf), but look at the units used. If the measure is weight, a heavy bit of ‘green’ insulation may be higher in embodied energy than a much lighter piece of ‘non-green’ insulation.
You may in any case wish to avoid wherever possible materials made from petrochemicals.
But ‘environment’ may mean more than ‘the world in general’. What about your immediate living environment? You may feel better in a room lined with vapour-permeable, moisture-buffering wood-fibre than in a room lined with petrochemical-based insulation.
6. Minimise thermal bridging
You may believe – perhaps because your builder or consultant told you – that having low (good) U values guarantees good performance but thermal performance may be let down by weak-points in the insulation layer. Typically this would be where partition or party walls interrupt the insulation layer, where walls turn into windows or doors, or where internal insulation has to be thinner to accommodate fixtures or fittings. In practice, your U value may not be as low as you believed it to be.
The picture on the left shows: on the left, a wall prepared for insulation to ‘return’ on to internal wall to cloak the thermal bridge; in the middle, Pavadentro wood-fibre board prior to plastering; and on the right an existing brick wall with a lime ‘parge coat’ (air-tightness layer) to reduce air-leakage through voids in the brick wall.
7. Minimise thermal by-pass
Thermal by-pass, or ‘wind-wash’, occurs when cold air is allowed to get to the ‘warm side’ of the insulation. This can best be explained in two scenarios:
The first is a loft-conversion. The eaves areas are cold voids. The stud walls to the room (which are built off the floorboards) have been insulated to a good standard but there is only 100mm of insulation between the 150mm floor joists.
The ventilation air which enters at the eaves vents (a good ‘howling gale’ to keep all the timbers healthy) can blow directly under the floor of the heated bedroom, providing instant cooling!
Small pieces of plywood or similar board, sealed at all perimeters, placed between the joists at the edge of the floor on both sides of the bedroom will cure the problem. ‘Plugs’ of quilt insulation placed in the gaps will not do such a good job (as quilt insulation is generally air-permeable), but will be better than nothing. Once these gaps have been sealed, the insulation should in any case be increased to approximately 300mm.
The second scenario involves insulation to the sloping ceilings above an attic bedroom, carried out, as the law requires, by roofing contractors when re-roofing the house.
The house was sold and the new owner decided to remove all the attic ceilings. All but about six of the sheets of insulation fell out from between the rafters. What this tells us is that, while the insulation was in place, the cold air in the ventilation gap between the insulation and the slates was able to migrate to the warm side of the insulation, rendering the insulation almost useless.
8. Plan to do it all!
Many insulation plans are carried out incrementally, perhaps as other work is required, or when a room needs comprehensive re-decoration or (externally) when the cost of re-pointing an elevation can be avoided and put towards the cost of externally insulating that elevation.
When planning your works, ideally plan to do the whole house, even if you know it is going to take you 10 years to achieve it. I’m 29 years in and starting to re-do the internal insulation using better materials and methods than were available in 1987! Plan how your individual works are going to ‘knit together’ so as to limit thermal bridges, where condensation and mould may otherwise occur.
Above all, you don’t want your works – undertaken with the best of intentions – ultimately to shorten the life of your house.
About the author
Nick Parsons has worked in energy-efficient and sustainable building and renewable energy for over 25 years. He provides consultancy and project management services to individuals, small businesses and community organisations and is a regular tutor at CAT and elsewhere. See www.sustainablebuilding.org.uk for details.
The next eco-refurbishment course with Nick takes place from 4th to 7th November. For more information and to book, please visit http://courses.cat.org.uk/ or call us on 01654 704966.
The next Zero Carbon Britain short course will explore ways we can deliver a climate positive future, while maintaining a modern lifestyle. We also look at how ZCB can be used successfully to inspire positive action, stimulate debate and build consensus in our communities and places of work.
Scholarship entries will be judged by a panel of CAT staff and announced on 17th August on the CAT Facebook page.
By entering, you accept that CAT will post the winner’s first name and surname initial to our Facebook page.
The prize includes all course fees and full board accommodation at CAT.
We are so excited about our tiny house courses – new from us to you!
Running three times this year, spaces are filling up fast.
Learn how to make a beautiful and bespoke tiny house from the ground up: including the timber frame structure, interior and renewable systems.
Carwyn Lloyd Jones, our very own master craftsman (and TV star!) will guide you through an inspiring and practical week where you’ll learn how to:
• Build a timber frame tiny house (approx. 6ft x 10ft)
• Clad the walls
• Build different roof shapes (including pitched roofs, curved roofs and green roofs
• Install windows and doors
• Fix the structure to a trailer base
• Create simple, functional and smart fitted furniture
• Integrate Solar PV and thermal for electricity and hot water
• Harvest rainwater
• Include a compost toilet
Jam packed with practical hands-on exercises and talks from experts, this course will give you the skills and enthusiasm to build a tiny house of your own – whether it’s a little off-grid home, outdoor workspace or a glamping pod for summer getaways.
Carwyn will also give you a tour of his very own tiny house caravan as seen on George Clark’s Amazing Spaces.
Here at the Centre for Alternative Technology, we run a wholly vegetarian restaurant. Catering for our own MSc. students, staff and people participating on our short courses, no-one goes hungry here.
In an attempt to showcase a low or zero carbon future, we demonstrate dishes and techniques that have a decreased impact on our environment.
Laura Blake, CAT nutritionist, says, “Reducing your red meat consumption is the single most effective and important thing you can do to lower your diet-related greenhouse gas emissions. It has also been shown to lower your risk of certain diseases: including bowel cancer – making it healthier for you too!”
Agriculture contributes to a third of the total carbon emissions, and the increase in conventional methods of farming poses a rising threat to the environment as the world tries to feed an additional two billion people by 2050.
We believe a low carbon economy is more energy efficient, more energy secure, cleaner, quieter and safer.
And more delicious, too.
So, here are five of our restaurants favourite breakfast dishes for you, to celebrate National Breakfast Week.
Porridge (serves two)
Oats are really low in greenhouse gas (GHG) emissions, so porridge is a low cost and filling way to start the day. Soaking the oats overnight reduces the cooking time.
160 g rolled oats
600 ml milk, organic soya milk or water
Toast the oats until beginning to turn brown; this gives them a nutty flavour.
Place the oats and the milk or water in a large pan over night.
In the morning, gently bring to a simmer, then add a tiny pinch of salt and stir.
Simmer for 5 to 6 minutes, stirring as often as you can to give you a smooth creamy porridge.
If you like your porridge runnier, simply add a splash more milk or water until you’ve got the consistency you like.
Adding fruit helps meet your five-a-day. Locally grown, low carbon options include: apple, pear, blackberries, raspberries, plums – at the right time of year, obviously!
Vegan Mediterranean Shakshuka (serves two hungry people)
In Israel shakshuka is often eaten for breakfast, but this super easy and versatile dish can be cooked or any meal of the day.
½ tbsp olive oil
½ small brown or white onion, peeled and diced
1 clove garlic, minced
½ medium green or red bell pepper, chopped
1 can chopped tomatoes
1 tbsp tomato paste
½ tsp chilli powder (mild)
½ tsp cumin
½ tsp paprika
Pinch of cayenne pepper (or more to taste– spicy!)
Salt and pepper to taste
1 block firm tofu, pressed and drained
½ tbsp fresh chopped parsley
Gently heat a deep frying pan (a cast iron pan is ideal for this) and add olive oil.
Add chopped onion, sauté for a few minutes until the onion begins to soften.
Add garlic and continue to sauté till mixture is fragrant.
Add the pepper, sauté for 5 minutes until softened.
Add tomatoes and tomato puree to pan, stir till blended.
Add spices, stir well, and allow mixture to simmer over medium heat for 5 minutes until it starts to reduce.
Taste the mixture and season it according to your preferences.
Slice the tofu along the width into four squares and gently place onto tomato mixture.
Cover the pan. Allow mixture to simmer for 10 minutes, or until the sauce has slightly reduced.
Garnish with chopped parsley, if desired.
A bowl of cereal
High fibre breakfast cereals with low sugar and salt content are useful as a quick fix – all cereals are pretty low in carbon and can be grown easily in this country. Sadly, with the average person in the UK still not meeting their five-a-day requirements, this is where a lot of people get a significant amount of their micronutrients from!
As a guide, muesli or a cereal with bran in its title is a good bet, but do check the sugar/salt content on the packet.
Lots of fruit will grow in the UK, especially if you can give it a bit of protection in a conservatory, greenhouse or against a south facing wall. Here in wet and windy Wales, we were still harvesting raspberries the week before Christmas, and enjoy growing some more unusual fruit – goji berries and honeyberries seem to do well.
One handful of any seasonal fruit – berries, plums, apricots, figs, currants
300ml milk, or milk substitute, or apple juice, or water and yogurt
2 tbs oats
If there’s time, prep the fruit the night before and store it in the fridge.
In the morning, buzz it together with a hand blender or liquidizer.
Beans or egg or scrambled tofu, with wilted spinach on toast
Commercially produced eggs are significantly higher in emissions than the other two.Can you keep a trio of ex-battery hens in your back yard? They take up less room than you think, will gobble up much of your garden waste and vegetable peelings and offer you an egg or two a day in return.
High protein foods should help keep you fuller for longer and stop you snacking!
Tofu has far less of an environmental impact than many would believe – it also has a high water content.
A handful of spinach, fresh from the garden, quickly cooked in a pan and added to either scrambled eggs or tofu adds both nutrition and taste.
Use wholemeal bread to boost the nutritional content, and top with herbs fresh from the garden – chives, parsley and marjoram all have additional health benefits.
Last year was full of firsts for us and a great coming together for all involved in the company. The first residential self-build frame for the county, the honing and strengthening of skills and relationships, and a great new website!
The movement towards low impact living is really gaining momentum with more and more people looking for alternatives to the mainstream. Questions about how we can live a more carbon neutral lifestyle are being asked, and there are so many people doing amazing things to answer them.
It always takes time for new ideas to filter through, and one of the aims of Ty Pren is to bridge the gap between self-builders and local councils. Roundwood timber framing provides a strong framework for affordable, low impact homes that are sustainable, beautiful and a big step in the right direction towards a zero carbon Britain.
Zero Carbon Britain and OpenEnergyMonitor are collaborating on a new open source energy model http://zerocarbonbritain.org/energy_model/ aimed at helping users explore and visualise how a zero carbon energy system could work. The model shows hour-by-hour how energy supply and energy demand match up, the back-up power required, and how energy storage can help to balance supply and demand. The model also allows users to explore how much biomass is required for back-up power and other fuels and to see if their choices add up to a zero carbon energy system.
Philip James of the Zero Carbon Britain team is collaborating on the model with Trystan Lea of OpenEnergyMonitor. The model fits in with OpenEnergyMonitor’s work developing open source tools that allow users to monitor, evaluate and understand their own energy use. Their intention is to try and relate in house monitoring of electricity consumption, such as heatpump performance and electric car charging, with information about renewable supply both onsite and from the grid. This could help answer questions such as: how much of my heatpump’s electricity is likely to be coming from wind farms in the UK? How much would be coming from wind farms in the future? And if there was significant storage on the grid when would that electricity be coming directly and when would it be coming via a store. OpenEnergyMonitor are also exploring the potential for automatic control of these larger energy uses depending on renewable supply availability.
One study they have undertaken already explores and visualises the changes needed to get around 20 actual households in North Wales from their current energy use and carbon emissions to zero carbon http://egni.ecobro.org/data . With an hourly zero carbon energy system model, this kind of community energy planning exercise can take into account the variability of renewable energy supply and energy storage considerations in addition to the ‘power down’ demand side solutions.
These tools aim to help make it easier to join the dots between individual action and understand what’s needed at the community, regional and country-wide scale to get to zero carbon.
As with ZCB and OpenEnergyMonitor‘s other work, the tool is freely available and open source. We’d really like those who are interested to get involved, either by giving feedback and suggestions for the tool’s development or for other work in this area. Those who are really keen can download the computer code and contributing to the development directly https://github.com/philJam/energymodel .