Personal Story:
One of us grew up in Cornwall (solid granite walls and open fires) and one in western New York State (timber frame houses with huge boilers and hot air heating). We met in 1964 on a Roman dig, married seven years later, and have lived in Birmingham for almost 34 years. We spent much of our lives in education (between us teaching primary school (15 years), archaeology in adult education and as a visiting lecturer in assorted universities (20 years) and lecturing in the business school the University of Central England (20 years)).
Most of the time we were bringing up our two sons we lived in a 4 bedroom detached house in Birmingham. In 1979 we used almost 42,000kWh of gas; our electricity use peaked at 6,500kWh in 1998. By 2009 we had reduced our gas usage 65% to about 15,000kWh and our electricity usage 70% to 2,000kWh electricity. Following the renovation of our “superhome” semi our gas usage is 4,000kWh and our electricity 1,400kWh per annum.
After retiring we acquired an allotment. Chris spotted the for sale sign on our current house when cycling back from the allotment. We had been considering how best to “downsize” from our by now well-insulated old home (HIP rating C) and wanted to experiment with super-insulating a semi-detached home for our retirement.
Motivations:
We first became aware of the warming effect of CO2 on our atmosphere when we saw the “Keeling Curve” in 1980 and waited to see how world governments would rise to this challenge. And waited and waited.
In 2005 we joined the Living Witness Project, a Quaker initiative encouraging personal responses to climate change. Joining with others we worked to reduce the energy usage of our Quaker meeting house 91% between 2005 and 2011 doing much of the work ourselves (https://cotteridgequakers.org.uk/sustainability)
We learned from this project what can be achieved and wanted to demonstrate it in a relatively “average” three-bedroom semi while customizing our home to suit our retirement within the constraints of the Bournville Village Trust design guide.
Our house was built in 1932 by the Bournville Village Trust. In the 1960’s the owners added central heating and extended the living room by about two meters. The extension had single glazed windows on all sides and little insulation in its flat roof.
There was about 6 cm of insulation between the rafters when we bought the house but no further insulation.
Measures:
Replaced the very inefficient boiler and re-plumbed the central heating–pipes below the floors are now positioned above insulation. Estimate new boiler 30% more efficient.
Insulated the walls both with cavity wall insulation and with interior cladding, achieving a U value of 0.2.
Upgraded the loft insulation to achieve U value of 0.1 on edges and 0.2 in central storage area.
Replaced the old single glazed windows with argon filled, soft coated double glazing; one window now triple glazed. Estimate U values went from 5 to 1.2 and 0.8.
Replaced an open fire with a smokeless wood burner. When the central heating is on we have a fire burning. We estimate the fire provides at least 30% of our heat in winter.
Installed 2.4 kWp solar PV on a garden pergola. This provides c. 1,800kWh over the year, equivalent to our annual usage.
Installed solar thermal panels on roof. These enable us to turn off our gas hot water for about 6 months saving about 900kWh.
Insulated under the floors.
Benefits:
We believe the home is now consuming about 85% less energy than it would have had we moved in without spending six months improving and insulating it. It is warm and snug in winter and cool and well ventilated in summer. Our bicycles take pride of place in the cycle shed carved out of the old garage. We take great pleasure in reading our gas and electric meters weekly, graphing our modest usage and trying to think of new ways to reduce it.
We are rather embarrassed to receive £200 heating allowance for a full year of gas which cost a total of £211. The main benefit or our PV electricity generation is our feeling of comfort knowing we generate just about what we use over a year. The feed-in tariff received will pay for the PV installation (including the pergola and armored cable) in a little over 15 years.
Favourite Feature:
Our favourite improvement is probably the cavity wall insulation–a huge improvement in warmth for a very low expenditure! That, however, is not a particularly visible improvement. On a chilly day it is a great pleasure to watch the flames from a wood fire in our smokeless wood burner while basking in its warmth. Our incessant search for unwanted local trees also has helped us integrate into our new community.
