Optimus (en-GB) | Going Green by Anne Briffett

It can be daunting making the transition to a greener lifestyle outside of work. But with the cost of energy going up and climate change looming there’s no better time to consider joining the transition to low-carbon energy for your home!

Read on to hear how Anne, our Principle Structural Analyst, made the leap to making her home more energy efficient, utilising the funding available from the Scottish Government.

Our home near Inverness is out of town and we have no mains gas or oil tank. We have 2 log-burning stoves and an electric boiler for hot water and heating and the only fossil fuel we have is bottled gas for the cooker hob. However, there are still ways we can go green, and we are by no means finished with our journey!

Our house is an old stone cottage with a new modern timber frame extension. We have already insulated the upstairs of the old part, and we are currently insulating the downstairs. This is involving ripping out the old lath and plaster, insulating with sheep’s wool and Parvatherm wood fibre board and re-plastering with lime. This should reduce the heating requirements in the old part of the house, which is heated with log-burning stoves and a bit of supplementary heating with electric radiators.

This summer, we had a 4.4Kw solar PV system installed on the east and west-facing rooves (as we did not have a suitable south-facing roof). However, this spreads power generation throughout the day, which is quite useful as it matches the peaks and troughs of our energy demand. You can see below we generated 19.8kWh on the 31^st of July (which was overcast).

In addition to solar PV, we installed a “solar power diverter”. Rather than exporting excess back to the grid, the excess power is diverted to a hot water immersion heater. In this way, we maximise the use of the solar electricity generated – the hot water tank acts as a thermal store. This is important as SSE will only pay us ~3p per kWh for exported power, so it makes sense to try to use as much of our home-generated power as possible. Batteries are also an option – storing energy for use later when required. We are going to see how much we generate, how much we can use and how much we can export before we consider batteries, but these could be the way to go for many people.

For heating the new modern extension and providing hot water in winter, we are going to replace the electric boiler with an air source heat pump. The modern extension is well insulated, but we will need to increase the size of the radiators, as the air source heat pump works at a lower temperature than regular wet central heating. Getting quotes was time-consuming and difficult. Most local installers were very busy indeed and struggled to provide quotes in a timely fashion. However, we did finally get 2 quotes despite speaking with 5 companies. We plan to pay for this with the maximum interest-free loan available (£10,000) plus the £7,500 cash back, so it should cost us £2,500 over 5 years (£42 per month). We spoke to Home Energy Scotland and they arranged for an energy assessor to call us to discuss whether it was an appropriate solution for our home. She produced an energy report which confirmed this. We then completed the online application form, which included the quote and the energy report, as well as other details. We are still waiting to hear back as to whether our application was successful. Fingers crossed it comes through soon so we can install it before Christmas. The air source heat pump should be about 3 times more energy efficient than our current electric boiler.

While we are doing all this, we are also installing an EV charger as we plan to buy a used EV at the end of the year using the interest-free loan from Transport Scotland. You can also get a grant of £300 towards a charge point if you are in a certain postcode or are applying for the used EV loan (although you need to get the grant before installing, so we did not go for this). The EV charger and solar power diverter will also divert solar power generated to the EV charger, again reducing the amount we might export and reducing the need for batteries.

All this seems expensive, but we think we will save money in the medium term. Payback periods are getting shorter as energy costs increase. Of course, we will start to reduce CO2 as soon as these things are installed which is good for the climate!