In October 2009 Chris and Harriet Martin bought a three bedroom, 1932 semi on the Bournville Village Trust in Birmingham.  We were down sizing from a four bedroom detached house, our family home for 32 years.  Over these years we had reduced the house's CO2 emissions from gas and electricity by about 70%, from 11,300 kg to c. 3,280 kg CO2, but were finding further reduction difficult.

We worked to make our new house as energy efficient as possible (in addition to modernizing it) before moving in.  A spreadsheet analyzing the original building materials vs. the planned improvements suggested it might be possible to reduce our carbon emissions by another 75% (to c. 800 kg)  by moving to a well insulated semi. 

 Over our first full year in our new house we used 5,685kWh of gas (= 1,171kg CO2) compared to 14,781kWh (= 3,045kg CO2) in our previous well insulated, but detached, home.  This was a 62% reduction in usage and a saving of 1,874kg CO2.  It was 371kg CO2 short of our target, however.  The hallway near the front door was a cold spot in winter months and we would like to improve this by adding an exterior enclosed entrance porch. 

The emissions from gas  were the total emissions from the home as a solar PV system now generates as much electricity over a year as we use (about 1,800kWh).  Solar generation of 1,800kWh of electricity saves 941kg CO2 compared to generation in a gas fired power station.  In total the new house has reduced our CO2 emissions by 2,815kg.