Housing – energy and utilities

Building with resources in mind

One of the stand-out points of Simon Tilley’s podcast episode was for me when he spoke about starting the Hockerton Housing Project.  Efficient use of locally sourced (where possible) resources during building and when lived in was at the heart of the design.  It was essential to view the house as a whole system, rather than just lots of distinct entities such as lighting, heating, water, to be bolted on later.

Heating

Using energy efficiently was paramount.  Heating was designated a priority, as it typically makes up 60% of household energy needs.  Through clever design, heating the Hockerton houses has been achieved without installing a central heating system.  Passive energy gains from the sunlight and body heat are generally sufficient to provide an even temperature of 18-23°C all year round.  The experience is apparently similar to a Mediterranean house.

We all know that sunlight is not a given in the UK, unlike other places such as California.  Therefore, storing heat is essential to maintain a comfortable temperature, from creating a thermal mass through building materials.   A lack of thermal mass results in a cold building in winter, hence the need for additional heating; in the summer, there is a greater risk of overheating when outside temperatures rise.  At Hockerton, heat is stored in the walls, by building the bricks on the inside and the insulation on the outside; the opposite way round to commonly built UK houses.  It seems perplexing to me; why are not more houses built in this more energy-efficient way?  Simon suggested a disconnect between the builder not being an inhabitant to gain feedback and weak building regulations as possible reasons.

Maximising insulation and airtightness are key to improving the energy efficiency of any home and saving money on heating.  Ideally, these factors are addressed at the design stage.  However, the reality is that many houses were built insufficiently insulated, and this will need to be addressed in the not too distant future to mitigate further climate change impacts.  In our house, windows with old seals have shrunk, exposing windy gaps in the corners!  Window replacement is our next stop.  In addition to maximising insulation and minimising air leaks, turning down the thermostat by 1°C can be hugely impactful.  This is obviously easier to do if you are operating now at a temperature of 20°C than at 18°C.

Electricity

Without additional heating at Hockerton, energy requirements are significantly lower; electricity is used for water, lights, appliances and most recently, charging electric cars.  They have a green electricity supply through their solar PV panels and wind turbine.  The alternative to having your own renewable energy sources is to access them through energy suppliers – green tariffs are widely available.

There are numerous tips to save electricity around the home; for example, replacing halogen light bulbs with LEDs.  Hockerton initially installed compact fluorescent lighting, as these were the most energy-efficient when installed, but replacements have been with LEDs.  Other saving possibilities include: washing your clothes at 30°C; only boiling water you need; not over-filling your fridge or freezer, so they don’t have to work too hard; switching appliances off when they are not in use (rather than on standby) where possible.

Water

At Hockerton, the houses are unconnected to the mains.  They collect rainfall from their roofs and store it in a reservoir (known as rainwater harvesting).  Apart from not having to pay a utility company for their water, it also affords them to visualise how much water they have.  A fall in the reservoir water level acts as a cue to be more mindful of their usage.

In England and Wales, the average daily water usage per head is 140 litres (Ofwat, 2016 data); this equates to filling your wheelie bin.  I think it’s easy perhaps to take the clean water we have access to in the UK for granted?  According to Friends of the Earth, 97.5% of water is in oceans and seas and is too salty for drinking.  Most of the remaining 2.5% is frozen in ice caps, so there is not a whole lot available to us.  The risk of water scarcity is expected to increase with ongoing climate change.  Viewing water as a precious resource seems like a good idea through being mindful of our everyday uses:

  1. Taps – fix leaks and don’t leave running.
  2. Showers – one minute can use up to 17l of water.
  3. Toilets – water-saving device in the cistern or dual flush.
  4. Washing machines – ensure full loads.
  5. Dishwasher – wins over hand-washing.
  6. Kettles – only boil what you need.  
  7. Garden – water early or late in the day.

Doing what you can

In our quest to live more sustainably, we can reduce our carbon footprint and use of resources, benefiting our pocket and the planet.  As always, I think it is about starting from where you are at and doing what you can.

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