ENVIRONMENTAL INFORMATION

From the moment of concept ‘Jack’ and ‘Jill’ were conceived to be built and run in as environmentally friendly way as possible. We were delighted to be awarded a immediate ‘Gold’ award by ‘Green Tourism’, their highest award.

ENERGY EFFICIENCY

Both ‘Jack’ and ‘Jill’ are insulated to a very high degree having twice the levels of insulation demanded by Building Standards in the late 2010s. As well as the strawbales themselves, there is 300mm of expanded polystyrene within the ‘dwarf walls’ (what the straw sits on to keep it 900mm above ground level) as well as under the ground floor.

This means that little heat is required to keep the houses toasty (we aim for 22 degrees Celcius) and the heat is provided by two Ground Source Heat Pumps. These extract ‘heat’ from nearby boggy land and using refridgeration technology (in reverse) to provide the space heating and hot water (always available at 57 degrees C).

The heat pumps have a ‘Coefficient of Performance’ (CoP) of 4.5. This means that for every unit of energy (one kilowatt hour) that they use they generate 4.5 units (or kwh therms) of heat. This makes much better use of the electricity, most on which is generated on-site by a 10kw hydro scheme and 6kw of solar panels (see below). We also have two 13.5 kwh Tesla Powerwall batteries to save any surplus power that’s generated and which also provide 27 kwh of back-up power during (rare) power cuts. If used carefully by the houses this is plenty for at least two days.

RENEWABLE ENERGY

Sunart Strawbale’s electricity is generated by a 10 kw hydroelectric turbine on the property as well as 6 kw of PV panels on a ‘Cornish Rocker’ frame and two Tesla Powerwalls (27 kwh of storage). This means that we import very little power from the grid and are actually a net exporter. Most years we export around five times more electricity than we import. When there is no renewable energy we import our power from a company that only supplies electricity from renewable sources.

As well as storing surplus power – to reduce imports – the Powerwalls function as an automatic back-up in the event of a power cut, producing up to 10kw for the two houses.

The ‘Cornish Rocker’ frames that the 16 panels are mounted on, can be manually tilted during the seasons to keep the panels perpendicular to the sun’s rays therefore maximising the power generated even in winter.

Guests can charge their electric cars at cost (~25p/kwh) using our 7kw Zappi charger.

GROUND SOURCE HEAT PUMP

Both strawbale houses are fitted with their own Ground Source Heat Pump. They use the same technology that’s in a fridge to extract heat from water that’s circulated around a 200m plastic pipe in a loop about one metre underground. This is a very efficient way of generating heat and approximately 1 unit of electricity (1 kwh) is used to generate 4-5 units of heat. It heats the water for the showers, sinks and bath and also for the underfloor heating.

These photographs illustrate the process of burying the plastic pipes. The field is now overgrown and the trenches quite invisible.

COMPOSTING & RECYCLING

We endeavour to minimise waste going to landfill by providing recycling options, not just for the standard glass / cardboard, plastics etc. via the Highland Council, but also by providing boxes for food waste recycling. These are emptied into a large compost ‘tumbler’ which provides great nutrition to the hundreds (thousands?) of worms living inside. The compost goes into our two polytunnels.

CLEANING PRODUCTS AND LOO ROLLS

We only use environmentally friendly cleaning products in the properties. Therefore we will provide ALL you need for your stay – toilet cleaner, surface cleaner, washing-up liquid, dishwasher tablets, laundry detergent and microfibre cloths. Please do not use any other cleaning products as this will reduce the effectiveness of our sewage treatment plant. We also provide six ‘Naked Sprout’ loo rolls.

WASTE WATER & SEWAGE

All waste water and sewage passes through a submerged aeration plant – a Tricel Novo 10. A combination of processes come together to affect the transition of wastewater into a treated liquid suitable for discharge back into the water table.

Initially the settlement of incoming wastewater and the separation of solids and liquids occurs. Effluent then passes into an aeration chamber where naturally forming bacteria consume the impurities. The final effluent undergoes a final settlement phase before being discharged into a soakaway.

The photographs illustrate the construction phase. Everything is now well hidden, buried beneath earth, grass and shrubs.