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Environment: treading lightly on the Earth
Environment: treading lightly on the Earth

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4.4.1 Low-carbon living

This section considers how one couple, Mark and Alice, have significantly reduced their carbon footprints by ‘eco-renovating’ their three-bedroom mid-terraced house in Oxford, England, without losing the benefits of a normal developed society’s lifestyle.

As you study this section, consider the questions in Activity 10 and think about the technical and lifestyle changes this couple have made to reduce their carbon footprint, as well as addressing some other environmental impacts. Think about which (if any) of these changes you might consider yourself.

Box 2 Eco-renovating

Mark and Alice’s philosophy

Mark and Alice’s aim is to show how a modern family can make serious reductions in their environmental impact, while still having a standard of living most of us would recognise. Above everything their aim is to be practical, rather than offer solutions that few people are likely to adopt.


Mark and Alice started by commissioning an energy audit of their house. This showed that their house was built to pre-1982 UK Building Regulations standards. Their plan of action included:

  1. Replacing the ancient boiler with a modern condensing boiler and installing new heating controls and radiator valves.
  2. Because of its cost, the case for installing solar water heating is usually marginal, but as they were having the central heating upgraded they decided to go for it.
  3. Insulation is key in any eco-renovation. Mark and Alice noticed the biggest change when they had the cavity walls filled with mineral fibre. They put sheep’s wool insulation in the loft, 100 mm on top of the 70 mm of fibreglass, and insulated the walls and ceiling of the internal garage to stop heat leaking into the cold space.
  4. Mark and Alice’s house had single-glazed windows plus secondary glazing. They decided to install the best double-glazed windows, and then refit the secondary glazing – triple glazing for a fraction of the price.
  5. Building a conservatory, which helps to heat the house in spring and autumn and acts as a heat buffer in winter. The conservatory was the largest investment Mark and Alice made. It’s a great space for relaxing and growing plants, and also improves the environmental performance of the house.
  6. Building an insulated front porch to stop cold air entering in winter.
  7. Mark and Alice cook, heat and provide hot water from gas, which has half the emissions per kWh of electricity. Gas and electricity consumption is about 50% lower than when they first moved in.


Mark and Alice try to save water. Lower hot water consumption also reduces energy use. Nationally, slightly more than a third of all domestic water is flushed down the toilet. A new UK toilet can use up to 9 litres a flush. They chose a Swedish design, which uses 2 or 4 litres a flush, but is indistinguishable from any other toilet.


Mark and Alice replaced their two cars with a (second-generation) Toyota Prius hybrid car. It cost little more than an average saloon, at the time about £17 500 minus a £1000 government grant, yet uses less than half the fuel of their previous cars. It has two engines, one petrol, the other electric, whose battery is charged when the petrol engine is running and by recovering energy when going downhill or braking. They get around 55 to 63 miles per gallon (5 to 4.5 litres per 100 km) of petrol, and it didn’t mean driving a really small car, or trading in comfort or safety.

They also decided to live close to the city centre and to public transport. They decided there was no point having an eco-house while having to travel long distances to and from work. They also got a couple of old bikes. These allow them to get around without always jumping into the car.

Mark and Alice have several relatives living in Canada and know that air travel produces very high emissions. If they travel to Canada about once every one to two years they know this can more than outweigh the CO2 savings they’ve made from eco-renovating the house.


Mark and Alice try to reduce their food impacts by: shopping in the local covered market for fresh, unpackaged food; using a box delivery of locally grown vegetables; growing fruit and vegetables on their allotment; buying local, ethically produced meat and eating it sparingly; and reducing consumption of imported and out-of-season fruit and vegetables.

Goods and services

Their house is small with no unoccupied rooms, which uses the available space and heating efficiently. Mark and Alice also like to keep the house uncluttered, which means not buying more goods than they really need or want and recycling unwanted items. As Mark says, ‘reduce first, reuse second, and recycle third’.

Beyond the household

Mark and Alice try to reduce their carbon footprint as much as they can, but recognise that there are limits to what people can do individually. They therefore help others to follow their example by providing information, if asked by friends or colleagues, and by contributing to eco-renovation open days and websites.

At the community level, Mark was chair of the Board of Westmill Wind Farm Co-operative from 2006 to 2015, which generates more than enough electricity to supply the demand of all the co-op’s 2500 members.

Mark and Alice also recognise that there are environmental issues that can be tackled only at government levels, such as local and regional planning and national energy, and transport policies. (Government responsibility for reducing emissions is discussed further in Section 5)

(Mark and Alice, personal communication and interviews, March/April 2008, updated 2016)

Figure 13 shows some images of Mark and Alice’s property and vehicle.

Described image
Figure 13 (a) The front of the house; (b) the rear conservatory; (c) the boiler and solar heat store; (d) Toyota Prius hybrid petrol–electric car

Activity 10 Low-carbon living

Timing: Allow about 10 minutes
  • a. What approaches to saving energy for heating etc. were adopted by Mark and Alice in their Oxford house?
  • b. What transport dilemmas have Mark and Alice faced in trying to live their low-carbon lifestyle?
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  • a.The approaches to direct energy saving made by Mark and Alice include:
    • insulation – as much as possible
    • draught-proofing, secondary plus double glazing
    • installing an efficient gas condensing boiler and controls
    • building a solar conservatory and porch
    • low-energy lighting
    • solar water heating
    • efficient appliances and cooking with gas
    • a small house with no unoccupied rooms.
  • b.Mark and Alice’s main transport dilemmas are:
    • wishing to visit their relatives in Canada about once every one to two years, which involves flights that more than outweigh the carbon savings they’ve made from improving the energy performance of their house
    • choosing low carbon transport for commuting, as the locations and requirements of their jobs change.

Mark and Alice are better off than many families in Britain and so could afford some of the more costly changes to their home, travel and lifestyle. But many of the changes they made cost little and often save money. There are many websites that provide information and inspiration for home eco-refurbishment, lower carbon transport options and other green technologies and lifestyle changes. Some give the cost of different actions, available subsidies and the time to pay back any expenditure involved.