CAT graduate Paul Martin shares his journey towards net-zero in his 1960s three-bedroom semi, showing that a modern low-impact lifestyle is possible for an average UK household.

In 2010, motivated by my visits and studies at CAT, I decided it was time to take steps to reduce my personal contribution to climate change. During my BSc, I recall seeing a case-study of a house in the UK powered by solar photovoltaic (PV) panels with surplus charging an electric vehicle (EV), and I thought, “I want to do that!”

Taking the first step

The first step was to understand my energy use. I did this by paying closer attention to my utility bills and taking meter readings for electricity, gas and water. I calculated the fuel consumption and annual mileage of my car. With the help of a carbon footprint calculator, I estimated the CO2 emissions attributed to my lifestyle (e.g. my diet and the things I was buying) and also to my share of UK infrastructure (services, roads, hospitals etc.). Using this information, I began to estimate my CO2 fingerprint – a detailed breakdown of my emissions across different categories (Fig.1) – and my total footprint (Fig.2), allowing me to track my progress towards net-zero over the years.

I purchased my house in 1995. I had a full set of data for 1998 before I’d made any changes to the property, so I chose this as the baseline year to measure improvements against. In 1998 my household’s footprint was 10.7 tons CO2e per year.

Lifestyle changes

I first began looking at the impact of my lifestyle choices, as these can be the quickest wins. Using the carbon footprint calculator, I came to a baseline figure of 1tCO2e per year.

To reduce these lifestyle emissions, I needed to make some changes. I changed my diet to vegetarian (later becoming vegan) and bought organic, fresh,
seasonal food from local farm shops where possible. I moved my finances to ethical banks, supported environmental charities (including CAT), and began living by the three Rs – reduce, re-use and recycle.

These choices reduced my annual lifestyle emissions by 50% or 0.5tCO2e per year. I generally found these changes simple to implement with little cost impact.

My household electricity use

Thinking about reducing my emissions at home, I began with my electricity use. Until 2012, all my household electricity was provided by the National Grid.

• In 2012 I installed a 1.8kWp (kilowatt peak) solar PV array on my south-east facing roof. I took advantage of the UK government’s Feed-in-Tariff (FiT) scheme at the time (now replaced by the Smart Export Guarantee (SEG)).
• In 2018 I installed a 4kWh lead-acid electricity storage battery to increase the proportion of the solar power I was personally using from 25% to 75% and reduce the amount I was exporting to the grid (after the six-year expected lifespan, I replaced the battery with a 13.5kWh lithium-ion upgrade).
• In 2022 I added a 1kWp secondary solar array on the south-west facing roof of my garage. I added more renewable power generation from a share in the Graig Fatha Wind Turbine Project.

All these measures were self-funded. But the payback in energy cost savings and revenue from the FiT and turbine provided funds for more measures.

As a result of these changes, my annual household grid electricity energy consumption has reduced by 34%, and my house’s emissions have been cut by 0.8tCO2e per year.

Heating

In 1998 the heating for my house and water were provided by an inefficient 1970s gas-fired boiler and radiators. There was no loft or cavity wall insulation. I had 1980s double-glazed windows and patio doors and leaky
wooden external doors.

In 2005, before I began consciously taking efforts to reduce my carbon footprint, I made some home improvements. I replaced my front door and patio doors and bricked up a side door. I replaced a flat roof. I insulated the main loft with 150mm wool fibre. And I replaced the old boiler with a 90% efficient gas condensing boiler, new pipework and radiators.

Later, taking advantage of a Welsh Government grant, I improved the
building fabric heat loss and infiltration by installing cavity wall insulation, topping up the loft insulation to 300mm, and sealing up areas where air was escaping. I replaced the windows with A-rated, argon filled, low-emissivity double-glazed units, trapping heat and maximising passive solar gain.
Then in 2023 I replaced the 18-year-old gas boiler with a 5kW air-source heat pump, electrifying my space and water heating. To do this I made use of a £7,500 UK Government grant*. In the first year of operation, this provided a coefficient of performance (COP) of 4.01. Essentially, every unit of electrical input delivers four units of heat, an efficiency of 400%, compared with 90% for a new gas boiler.

These measures reduced my annual space and water heating energy consumption by 84%, and my emissions by 2.7tCO2e per year.

Travel

As a wheelchair user, all my personal travel is by car. At the end of 2011 I changed my petrol car to a mild hybrid, saving 1.4tCO2e per year. Three years later, I was able to upgrade again to a 100% battery electric vehicle, saving a further 0.5tCO2e per year.

In 2024, due to a greater proportion of grid electricity coming from renewable sources, particularly wind, my annual car travel emissions were reduced by 79% or 2.2tCO2e per year. This is despite my mileage increasing by 4,000 miles a year.

The electric vehicle can also be charged purely from solar in summer due to the addition of the secondary solar array – zero cost, zero emissions.

Water consumption

I’ve reduced my water consumption through water harvesting, installing low-flow gadgets on outlets, the use of a shower timer, taking showers over baths, and using a dishwasher rather than filling the sink. My annual water consumption has dropped by 80%, resulting in emissions reductions of 0.04tCO2e per year.

Infrastructure

The infrastructure we use, like services, roads, hospitals and so on, have CO2 emissions attributed to them. These are not personally controllable, so they have remained constant over the period.

The figure was derived from the carbon footprint calculator I used – 2.75tCO2e per year for each UK citizen.

To offset some of these emissions, I used natural sequestration through an annual donation to the Woodland Trust to plant 25m2 of woodland. I planted 14 native trees on-site, created two ponds, grew a green wall, and put an extensive sedum green roof on my flat-roof extension. I’m fortunate to have a large garden which allows me to do these things.

Overall impact

Due to the measures described above, by 2024 my total carbon emissions
had been reduced by 79% or 8.5tCO2e per year compared with the 1998
baseline, from 10.7tCO2e to 2.2tCO2e.

Furthermore, my personally controllable emissions, omitting infrastructure, produced a negative figure of -0.5tCO2 e in 2024. Fig. 2 shows the carbon emissions reduction over the period, comparing my total footprint, personally controllable emissions, and the UK per capita target.

About the Author

After studying a BSc Environmental Studies and Diploma in Environmental Policy then an MSc Sustainability in Energy Provision and Demand Management at CAT, Paul now writes articles and a blog at ecofuturist.net about achieving his net-zero carbon lifestyle. He is also a co-founder and director of EVA Cymru, Wales’s national representative body for electric vehicle owners and drivers.