William started his home energy efficiency journey by lending a thermal imaging camera from Cambridge Carbon Footprint loan scheme in 2022, he is now Home Energy Officer at Cambridge Carbon Footprint.
Going to see a talk by Rob Hopkins, cofounder of the Transition Network, on his then new book ‘From What Is To What If’ at the Cambridge Literary Festival. I started looking at my own carbon footprint and then looking at ways to improve the energy efficiency of our home.
To improve the energy efficiency of our home, reduce our carbon footprint, arrive at lower annual energy bills and improve the quality of the internal space, not too hot not too cold or draughty and with good air quality. Gas consumption is down ~20% and electricity purchased down by ~60%. A significant cut in carbon footprint. Bills are down especially electricity which is down 80%.
We started with an analysis of the energy consumption of time of day and time of year and a survey of the house with thermal imaging cameras, from CCF, and air-tightness testing. Phase 1 set about improving the fabric: more loft insulation, draught-proofing, double-glazing, two new patio doors and an MVHR system. Phase 2 was fitting solar PV panels and battery storage.
We combined this with re-roofing the cedar shingles on the south facing roof, that were due for replacement after 30 years. We needed a lot fewer shingles with in-roof PV panels making up most of the roof area.
INSULATION INSTALLER: DIY
This is the retrofit feature Fiona is most pleased with, for the improved air quality and the summer bypass air purge feature you can run at the press of a single button to bring cold air in to the house on hot stuffy nights. The vents are very discrete and completely silent in normal operation and just audible during a purge. The price ~£12,000 seems reasonable.
Jason at Temperature Management Group Ltd. took enormous care, discussed everything very fully with us before doing anything and worked closely with Vent Axia experts to specify and commission the system.
New double glazing where original single glazed windows remained and replacing perished double glazing units on the sunny south side. Total cost ~£6,000. Two new custom double patio doors from Eterno windows to replace leaky and high heat loss original crittal patio doors.
We are particularly happy with our new patio doors which are exceptionally well designed, the contractors who came over from Italy took exceptional care designing the doors and did a great job coming back to fit them. The 17-week lead time was well worth the wait! At ~£7,500 a pair they were not cheap, but beautifully made and a very low u-value for very low heat loss. My review and picture of our doors are on their website at https://eterno-uk.com/excellent-reviews/ from William O.
As we have a cedar shingle roof we need to use an in-roof systems. The system fitted has:
– 12x Jinko 440W Tiger-Neo Solar PV Panels in GSE in-roof trays
– 5kW SunSynk Single Phase Hybrid Inverter
– 2x 5.12kWh SunSynk batteries
– Eddi Diverter to allow us to power our hot water immersion heater
Optimum Electric, from Peterborough, were chosen as they could also do all the roofing work (new cedar shingles) and at ~£12,000 for the solar & storage system, competitively priced. They were very professional throughout and a pleasure to do business with. Apart from the two minor issues mentioned below, they have given excellent service before during and after installation.
It all works fully as expected. The Eddi Diverter was not actually required but they forgot to wire up the Inverter’s auxiliary output, so was a work around they included at no extra charge. Very pleased with the 80% reduction in electricity bills, we should be in profit in ~10 years!
Not so pleased that I have been unable to program the SunSynk Inverter automatically from my HomeAssistant gismo to make use of free or very low cost tariffs when outside of the nominal 23:30-05:30 Octopus Intelligent Go tariff cheap rate period. I need some extra connectivity on the Modbus provided for remote monitoring.
The solution needed for our home was quite specific to our house we needed to analyze the issues, educate ourselves and find the right installers. It took several years and we are not done yet, it’s a journey,
| Energy Consumption | Electricity (kWh) | Gas (kWh) | Wood (m3) | Total |
|---|---|---|---|---|
| Before | 4780 | 26453 | 3.0 | 0 |
| After | 2737 | 20599 | 3.0 | 0 |
