Project 8: Croftgary Energy Optimisation
This page describes a project that I undertook with my husband to reduce our family carbon footprint, including home energy measures, transport emissions and holiday travel.
This design was carried out in conjunction with my husband Scott Egner, with a great deal of input from Shirley Paterson, our Green Deal Assessor, and Steve Cook, fellow Permaculture practitioner. For this design we used "The Simplest Design Process" as discovered by James Chapman. This project evolved through several iterations and I found that this design process was very conducive to this highly iterative process as it kept us focused on our overall objectives.
The project invoked many Permaculture Principles, but the over-riding ones were to Integrate the Use of Renewables to Catch and Store Energy in order to Obtain a Yield. This project successfully delivered all of our objectives to significantly reduce our carbon footprint, improve the quality of our life through a more comfortable home, and to become more self sufficient and sell any surplus energy.
A video presentation of this design is available on YouTube: youtu.be/u8dh9d9fPe8
Our overall aim for all things at Croftgary is to be as self sufficient as possible and share/sell any surplus (Fair Share), including energy. However, we also have a very strong desire to reduce our carbon footprint as much as practicable and affordable (Earth Care), whilst still maintaining a reasonable quality of life (People Care). We wanted to apply these objectives to the energy efficiency of our home, our transport and our holidays. We planned to evaluate the success of the project by monitoring our emissions over the course of the project, our costs and our personal satisfaction and well being.
Home Energy Efficiency Improvements
We performed a variety of surveys and maps of the house, including temperature monitoring upstairs and downstairs. We also employed Shirley Paterson of NextGenergy, who is a Green Deal Assessor to survey the house and produce an Energy Performance Certificate. Shirley was also able to advise on what funding grants and other financial support was available for making our home more energy efficient.
We listed our resources:
- Land to grow firewood
- Existing central heating system (oil boiler, radiators, hot water tank) & wood burner
- Double glazing
- Some savings
- Clothes, slippers, carpets, rugs
- Financial limitations
- Limitations of open fireplace in the living room
- Limitations of chimney, flue & air circulation (draw) of kitchen chimney
- No connection to gas main
- Concrete floor in kitchen so no space for underfloor insulation
- Timer frame extensions limited insulation options
- Limit to how much time and energy we want to spend chopping wood for fire
- Awareness that we are approaching middle age and may not be fit to do a lot of manual labour in years to come
We moved to Croftgary in January 2016 and spent the first year getting to know the house to see how the current heating and energy systems were working. The house began as an old stone two room, one storey farmhouse. Previous occupants have extended the house in The house is in a rural location and not connected to the gas mains system. It was fitted with a oil based central heating system which provided heat and hot water. The kitchen also had a wood burning cooker installed, complete with a back boiler which would provide hot water. In principle, this stove seemed to perfectly embody Permaculture values as it used a renewable source of energy (wood) and provided three functions (heat, hot water and cooking). The system was designed such that the wood burning stove and back boiler would have the capacity to get the water sufficiently hot to run the central heating, at which point the boiler would automatically switch off.
House energy systems - observing and interacting
After 18 months of failed attempts to get the stove to heat the hot water we had an electrician rewire the system and eventually we got it to work as designed (Oct 2017), but only by dropping the automatic temperature change set point significantly. It became apparent that the wood cooker would never really provide enough heat to run the central heating or hot water, and we would always be dependent on oil. In addition, the presence of solid fuel cooker forced us to have the water tank and overflow radiators upstairs on permanently as a safety feature. The temperature upstairs was always stiflingly hot, forcing us to open windows to let out heat, whilst downstairs was always too cold.
An infrared temperature gun and a mercury thermometer were used to measure the air temperature and that of various surfaces around the house under different weather and heating conditions. The temperature of the floored loft upstairs (playroom) was always 1.5-5C hotter than the kitchen downstairs. On a sunny day the upstairs area would receive passive solar gain whereas the kitchen didn't, and on a rainy day upstairs would still be too hot as either the wood stove was on and the heat was sucked up the chimney-like staircase and/or the overflow radiators would be on permanently.
A SWOC analysis identified many other areas for improvement throughout the house.
- Roof space is very well insulated
- Oil boiler is A rated
- Windows are all double glazed
- Lincar stove uses wood for cooking, heating water and central heating so is very multifunctional.
- Upstairs is always significantly hotter than downstairs (2-5C).
- Lincar stove is tied into hot water tank upstairs, which therefore needs overflow radiators constantly turned on as a safety device, pumping even more heat upstairs.
- Kitchen floor is always very, very cold
- Open staircase to upstairs playroom acts like a chimney, drawing the hot air from the kitchen upstairs to the already hot playroom.
- Very little solar gain downstairs due to the orientation of the house.
- Central heating is based on oil, which is expensive and has high carbon footprint.
- The south facing door has single glazed glass panel, is poorly fitting and is very cold.
- Double glazed windows are all at least 14 years old.
- Water tank is small and only holds water for half a bath.
- Hot water pumps are fragile and easily broken (had to replace two within 2 years).
- Loft floor not big or strong enough to take a decent sized thermal store.
- Lincar stove constantly needs to be fed if it is to be used for cooking and heating.
- Kitchen only has one small north facing window, with thick black panes, and is very dark all year round.
- Space on land for wind turbine, solar array.
- Potential to use upstairs space as living room instead of playroom.
- South facing roof on extension has space for solar panels.
- Upstairs space is warm and good for germinating seeds and fermenting home made wine.
- Can grow our own firewood.
- Lincar stove has been poorly installed and allegedly breaks some safety regulations.
- Stopping hot air from going upstairs.
- Open fire place in the living room creates lots of drafts - chimney balloon was sucked out during last storm.
- Keep bumping head on coombed ceilings upstairs.
Ideas and research
We spent some considerable time looking at different options that might be applicable for our home, including consulting with fellow Permaculture colleague and green technology installer Steve Cook. Pinterest was used to store ideas.
We used a brainstorming session to help prioritise our efforts initially on reducing our energy consumption and then on minimising the environmental impact of any energy we did need to consume.
We obtained quotes and energy calculations for various options including Central Mass Boilers, Thermal Stores, ground source heat pumps, wind turbines, solar thermal, solar PV, solar batteries, SunAmp thermal storage, external wall insulation, triple glazing, draft proofing etc.
We assessed the various technologies, combinations and permutations according to set criteria.
- How much energy would be saved by insulation/glazing/ draft proofing etc vs costs and carbon footprint/ "eco/people friendliness" of materials to be used.
- Cost/affordability of installation and operating costs, as offset by any incentives that may be available, such as Renewable Heat Incentive, interest free loans, Feed in Tariff etc.
- Environmental impact of emissions and materials of construction
- People Care - how much effort would be involved in operating and maintaining the system, including wood processing.
- How dependent would the system be on external inputs, such as electricity from the grid, biomass pellets, and would it cope in the event of a power outage?
Phase 1 implementation and Action Research
Wood stove re-wiring
As mentioned above, we had the existing wood stove and back boiler re-wired to allow the wood stove to take over from the oil boiler once the temperature was hot enough. Whilst this was successful, in that it achieved the correct operation, it highlighted that the stove needed to be continuously fed with huge amounts of wood to be able to reach the temperature required to take over from the oil boiler. It became apparent that this was not a realistic option as we had neither the man power nor the wood to achieve this.
Blocking off stairwell
One of the issues we faced was of the open stairwell between the kitchen and the playroom upstairs acting like a chimney and effectively sucking the hot air from the kitchen up into the playroom. Given that the playroom already received solar gain from the windows plus heat from the water tank and overflow radiators, this room was stiflingly hot. We tried many temporary ways to block off this stairwell, including making a cardboard hatch and using plastic sheeting to "glaze" the stairs. We also got quotes to permanently glaze the stairwell with glass but this was both prohibitively expensive and would have made it very difficult to get furniture up and down the stairs. In the end the removable plastic sheeting proved to be reasonably effective as it stops a lot of the heat from escaping upstairs whilst still allowing the light from the upstairs windows to reach the kitchen.
Temperature monitoring showed that the upstairs playroom was consistently 1-5C higher than in the kitchen. We attempted to pull some of the hot air from the playroom downstairs into the kitchen using a fan and piping, as demonstrated on www.heatstick.com. Unfortunately, although we did see a temperature increase of 0.5C downstairs, the movement of the air acted as a draft, making it feel even colder and so this methodology was abandoned.
The windows in the kitchen and spare bedroom were West facing and double glazed but very old and had large black supports in the middle, letting in little light and a lot of cold. These were replaced with new double glazing, without the central pillar. The kitchen window was also extended down to the floor, letting in vastly more light to the kitchen. This was supplemented with a mirror placed outside the window to reflect the Eastern sun into the kitchen in the mornings, which has been very successful. We also painted the kitchen, changing from a dull grey colour to a palette of yellows, which gives the room a much brighter and more spacious feel. The new window draws the eye to the garden and allows views of the bird feeders and flower beds.
Self-regulate - modify dysfunctional behaviours
On paper the Lincar wood burning stove seemed to be the epitome of Permaculture - it served three functions (cooking, heat and water) and used a sustainable fuel source.
For a long time we kept including this stove in our design as it seemed too "Permie" to take out. Eventually we performed a Positive, Minus and Interesting (PMI) analysis and finally accepted that that the negatives (poor energy efficiency, high level of manual labour, very poor heat distribution, questionable safety of the installation) were far outweighing the positives. The stove had to go. Once this decision had been taken, it made the rest of the design much easier.
The design and implementation
Masonry stove for heat and cooking - catch and store energy; produce no waste
We wanted a design that would reduce our carbon footprint, not be too labour intensive, provide a comfortable home, see us with some resilience in the event of a power cut and give us some level of self-sufficiency.
To achieve this we decided to replace the Lincar stove with a more efficient Masonry stove. We had installed a huge masonry stove at great expense in our previous home (see Cairneymount design) and although we really enjoyed the heat and the look of that stove we did not want anything as big, or the scale of the installation process. In this respect it was nice to have learned from previous designs. We found a company who manufactured modular masonry stoves (Ecco Stove) and a company (Gondwana Green Heat) who were able to install the new stove in the footprint of the Lincar stove with minimum mess and time. We had also learned from our experience at Cairneymount that a wood stove is only financially advantageous if you have your own source of wood. To that end we planted a 5 year rotation willow coppice within our land to provide a long term source of free wood, and also formed a good relationship with local tree surgeons who are happy to bring us logs as it saves them paying to dispose of them.
The Ecco stove is most efficient in the coldest months of the year when there is the largest temperature differential between indoors and outside. This is also the time of year when we spend most time indoors and are available to load the stove 3-5 times per day, which then provides enough heat to most rooms of the house at a comfortable temperature. The bedrooms are furthest away from the stove and therefore coolest, which is what we prefer. the kitchen, living room, playroom and office are closest to the stove, most used during the day and are the warmest. We deliberately chose not to connect the stove to a back boiler as, although that would provide hot water, it would create the same problems as the Lincar stove, requiring a hot water tank and overflow radiators upstairs, making upstairs too hot yet again.
The masonry stove can also be used for slow cooking casseroles and for keeping food and water warm. It is not dependent at all on electricity and will therefore be able to provide heat and limited cooking facilities in the event of a power failure.
PV Panels and Air Source Heat Pump - catch and store energy; harvest whilst it's abundant
One of the first things we did on moving in to this property was to change our electricity supplier from Scottish Power to Good Energy. Whilst we appreciate that the electricity supplying our home is coming from the grid, and therefore is likely to have been generated from fossil fuels, nuclear or hydro, by buying our energy from Good Energy we are supporting the use of renewables.
We wanted to replace our oil boiler and as we are not near to a gas main our options were very limited. We knew we wanted solar panels but weren't sure whether to go for solar thermal or PV. When our energy advisor, Shirley Paterson, informed us that we would be eligible for the Renewable Heat Incentive if we installed an air source heat pump, it became clear that this would be our most affordable option. It would tie in with PV panels (for which we would receive Feed in Tariff) and it would allow us to replace the oil boiler, almost for free. We would also be eligible for an interest free loan from the Energy Savings Trust which would provide the capital, which would be paid off largely by the RHI payments.
The air source heat pump also provides some level of luxury in that we are able to set a timer and have the house be warm in the mornings before we light the masonry stove. Another advantage of the heat pump is that the water tank is located downstairs so upstairs is not too hot, and the removal of the old water tank freed up a large cupboard upstairs.
The air source heat pump works most efficiently when there is a small temperature differential between indoors and outdoors, and is therefore optimal in spring, early summer and autumn. This is also when the PV panels start to produce more electricity which becomes available to run the pump. In the height of summer, when the PV panels are producing most electricity and the air source heat pump is not running is when most of the surplus is fed back into the national grid. This video gives more information on how air source heat pumps work.
The masonry stove works best when there is a maximum temperature differential between indoors and outdoors and is therefore optimal in winter. Although the masonry stove consumes most wood during winter, the wood for the masonry stove is harvested and processed all year round and so the labour is spread across the year. We also have the option of storing the wood and then processing it when we have spare time. The graph below shows approximate representation of the peaks and troughs in energy generation and consumption and how the different systems are used to optimise the efficiency of each one.
The only time where would be excess energy is during summer when there is potential for the PV cells to generate more energy than is used by the air source heat pump for heating water. However we also use the PV panels to charge our new electric car and electric cargo bike, as well as running appliances in the house, including washing machine and induction cooker. In summer time we are also more likely to use the electric slow cooker whilst we are out working in the market garden, which again uses up most of the PV generated electricity.
Elements and functionality
The combination of masonry stove, PV panels and air source heat pump gives us a system where most elements serve more than one function, and most functions are served by more than one element, giving us greater resilience across the system.
In order to make the most of the heat from the masonry stove we moved the office from upstairs to downstairs, next to the kitchen. This is much more convenient (it was only upstairs in the past to capitalise on the excess heat up there) and this room is used much more now, and filing gets done more often....well, slightly more often!
Wood processing occurs in the area immediately north of the house, and wood stores are located around most edges of the house, as close to the masonry stove (in the kitchen) as possible. The old boiler cupboard, located just off the kitchen, is now used to store wood indoors, and is brought inside and kept in recycled shopping trolleys, which means the wood is only handled once and heavy lifting is kept to a minimum.
Our recycle bins are kept outside the kitchen door, and we have an outdoor larder (a recycled chest freezer) at the north of the house, immediately outside the utility room door, which is used as the main door.
Further Actions to Take
In the course of our research we identified other potential options to reduce our carbon footprint and save more energy but they were unaffordable/unrealistic at the time, but they are things we will keep in mind and perhaps initiate as they become more affordable and available.
- Replace more doors and windows as needed/affordable.
- Seal living room open fire chimney
- Consider means to store excess electricity when more affordable (e.g. solar battery, SunAmp)
- Consider external wall insulation if it becomes affordable and is breathable.
Post note: Winter 2019 we installed temporary plastic tertiary glazing to the patio doors in the living room and master bedroom, cutting down drafts and heating bills considerably.
We live 2 miles from our nearest village where our son attends primary school. I work 6 miles from home and Scott works 16 miles from home. There is no public transport to our house although buses and trains are available from the village. Scott works a random shift rota which precludes the use of public transport. The cost of public transport to Scott's workplace is also highly prohibitive, as is the very poor reliability of the service.
We live on a B road, with very fast moving traffic, at the top of a steep hill. This is suitable for experienced adults to cycle on, but is not ideal for children, especially cycling uphill to the house. There is no paved footpath into the village and conversations with Fife Council revealed that the reinstating of the overgrown footpath is not a priority for them. There is a farm track into the village but this is either very wet and muddy in winter, and overgrown with nettles in summer and autumn. It is passable in spring, making walking home from school viable if you have the time (30 minutes) and inclination for a few months of the year.
We continued to use the Simplest Design Method for this part of the design, listing our resources, limitations and also what we need transport for.
- Bicycles; good health, walking boots;
- 2004 Toyota Corrola
- 2006 Vauxhall Vectra
- Trains to Edinburgh and Fife from Aberdour Station, although very expensive and unreliable.
- Buses to Edinburgh and around Fife from Aberdour, although very expensive and time consuming.
- Entitlement to taxi service to/from school.
- Charge points for electric cars at Aberdour train station and across the country.
- Main road not ideal for walking or cycling to school.
- Unwilling to send child to school in taxi at this age.
- Time to walk to/from school is at least 30 minutes each way - this would use 2 -2 1/2 hours a day.
- Hours of public transport not useful for Scott's work.
- Access to Croftgary is very tight and limits the size of vehicle that can be driven in to the yard.
- Take Euan to school and short trips around Fife (max 10 miles).
- Scott commute to Edinburgh airport.
- Monthly visits to family members in Kelso and South Lanarkshire.
- Want to be able to take camping gear and bikes on holiday (so room for 3 passengers plus cargo).
- Vegetable deliveries around Aberdour.
- Want to be able to move large objects (e.g. pallets, bike boxes, bikes etc).
- Be able to take group of kids on days out.
Research and Ideas
We attended the EV show at Edinburgh Ingleston and at Dundee to look at Electric vehicles, however most of them were either out of our price range or had too low a distance range for our needs. Ideally we would like to have a van/people carrier for camping holidays with bikes, but none of the options were financially viable. We arranged for several test drives and found it interesting and frustrating that most car dealerships were not interested in selling us an electric car, probably due to the long waiting times for these vehicles.
Scott's persistence finally paid off when we were made aware of a new demo model Zoe that was going to become available. This new model had a large enough range, but with a second hand price tag which made it affordable. We received this news at the same time that we found out the Toyota Corolla was going to need a very expensive repair that would cost most than the value of the car. It was therefore easy to make the decision to replace the Corolla with the Zoe.
It was at an EV show that we first discovered eCargo bikes which looked like a potential option for covering the school run and short distances around Fife. We went to the Edinburgh Cycle Coop and tried a few bikes. Amazingly, the cost of a new ecargo bike was similar to the cost of a new car, with much less functionality. However, we were lucky that my preferred model was available as an ex demonstration model and therefore we received a significant discount.
During our initial PDC with James Chapman we played a game called Carbon Footprint where we very quickly learned that the impact of air travel is massively more important that any other action we take as individuals in managing our carbon footprint, and therefore we wanted to include how we travelled on holiday in our carbon footprint design, partly to remind ourselves to make eco-friendly choices, and partly to demonstrate to others the impact of air travel.
Although we haven't especially used a permaculture design for this aspect of our lives, we have chosen to include it here as we have applied permaculture ethics to our holiday decision making from 2019 onwards.
In 2017 we took a package holiday to Mallorca, In 2018, although we were aware of the climate impact, we travelled to California to visit friends who we hadn't seen in a very long time. As seen from the charts below, this has a huge environment impact. We did have standby tickets, so that we were only able to fly if there were spare seats on the plane, thus not technically creating a demand for the flights and potentially reducing waste for the airline.....but this is just me clutching at straws to justify a trans continental flights! For 2019 we have chosen to take a train to Cornwall to stay in a caravan. We could have chosen to drive our electric car which would have been completely free, but the reality of People Care prevented us as the drive would have been very stressful and taken a lot of time. We would also have been charging the car from the grid, which would use up indirect emissions, depending on how the energy had been generated.
Our house was re-assessed by Shirley Paterson following all the energy improvements and was found to have improved from Band E to Band C. Looking at energy (kw/hr) needed to run and heat our home, we reduced the demand by almost 50% due to the air source heat pump and masonry stove being significantly more efficient than the oil boiler and Lincar stove.
When we compare household, transport and holiday emissions it is clear that the biggest contributor by far is from our flights to California, and secondly from the oil central heating. Taking an average between 2016/2018, we cut our total emissions (kg CO2 equivalents) from around 18,000 kg to 1,800, reducing by 90%.
Fair share and financials
Looking at operating costs alone, our new system should save us around £600 per year, based on 2018 oil and electricity prices. However, in reality oil prices have increased by 20% just in the last year, so we should be saving £1100 per year based on today's (2019) prices.
We are exporting around 50% of the energy we generate, which contributes, albeit very modestly, to the amount of energy from renewables available to others via the grid.
We evaluated the installation costs along with financial incentives such as the Feed in Tariff (FIT) and Renewable Heat Incentives (RHI), energy produced by the PV cells and savings from lower operational costs to determine if these changes had been financially beneficial or detrimental. When everything was added up we found that the savings (based on 2019 oil prices) and incentives would cover the cost of the PV, air source heat pump and masonry stove within 25 years, but would not cover the cost of the windows. Obviously, if the price of fossil fuels continue to rise then our savings become more significant.
Overall we are very pleased with changes we have made and feel that we have a more comfortable home and more robust system in the event of a power outage.
Our son has outgrown the ecargo bike so we may sell this on as it is not being used anywhere near enough as expected - although this is largely due to us now using the Vectra more to collect cardboard wherever we go to mulch the forest garden.
This design took over two years, a HUGE amount of research, evaluation, debate and discussion.It has easily been the most challenging and frustrating design to date as we were overwhelmed with all the different options, many of which would have been financially beneficial but wouldn't have met with our permaculture ethics, and those that would have perhaps have best met our ethics (e.g. external wall insulation) were not financially feasible due to lack of incentives.
The Simplest Design Process worked very well for this design as it was a very, very iterative process, with ideas changing continuously as our research revealed more and more potential technologies to be evaluated This process led us to keep returning to our original brief which really helped us to focus on our objectives when trying to make decisions.
Using PMI (Positive, Minus, Interesting) was especially useful in this design as it helped us to break the deadlock regarding the Lincar stove which had been holding up the rest of the design.
One of the nicest things about this design was to be able to incorporate what we had learned about masonry stoves and wood supplies whilst living in Cairneymount. I believe that this learning has saved us a lot of pain and a lot of money.
In the end we are very happy with the combination of technologies as it gives us a balance of self sufficiency (via wood chopping and PV electricity) and comfort via the air source heat pump timer. We have some control over our costs depending on how much effort we are prepared to put into wood processing.
This design used some large, expensive, high- tech solutions (PV, air source heat pump, replacement windows) as well as some small, cheap and low tech solutions (draft proofing, mirror outside the kitchen window, repainting the kitchen, chimney balloon etc. Where possible we always choose the small easy solutions, or "low hanging fruit" first. Only when they don't work do we move on to the larger more complex solutions. In some instances the small solutions didn't work (e.g. heat stick, loft closure) but we have found that it's always worth a try - and sometimes it's the right idea but we may need to change the implementation (e.g. now that we don't have the hot water tank and overflow radiators upstairs it might be worth revisiting trying to close off the upstairs room when the stove is on to conserve more heat in the kitchen).
This design incorporated many design principles. We spent a lot of time observing and interacting during the survey and action research stages of the design. Our finished design integrates a diverse range of solutions, some of which are small and slow solutions, using renewables to catch and store energy whilst producing no waste. We self regulated our dysfunctional behaviours regarding the Lincar stove. Finally, we captured many different yields - solar energy; firewood; heat energy from the air via the air source heat pump and also much pleasure from a more comfortable house, sunnier kitchen and fun with the ecargo bike.
Many, many thanks go to:
- Scott Egner - this was a joint design with Scott Egner, fellow Permaculture designer and practitioner and long suffering husband
- Steve Cook of Interzone heating solutions for his infinite patience and many, many, many discussions of potential energy technology combinations and permutations
- Shirley Paterson of NextGenergy, for being our Green Deal Assessor, Energy Performance Certificate surveys, infinite patience and advice on grants, FIT, RHI etc, and general hand holding through all the paperwork.