Energy Saving Case Study 12
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House Age: Post War (1940 - 1970)
Energy Saving Improvement 1
Type: Solid Wall Insulation
Contractor: Zest Energy
Description: 100mm phenolic foam board mechanically fixed to external wall surface with an acrylic render and brick slip finish at lower level.
Cost: £0- (value £10,000 in 2013)
Energy Saving Improvement 2
Contractor: British Gas
Description: Worcester Greenstar 30 SI mains gas condensing combination boiler
Cost: £2,467 (2012)
Energy Saving Improvement 3
Type: Loft Insulation
Description: 250mm glass fibre insulation quilt laid between and over the ceiling joists
Cost: £0- (value £249 in 2012)
Energy Saving Improvements Details
This is a 2 bedroom semi detached house built in 1943 orginally as a council owned property. It has solid brick walls and a pitched roof and is in a fairly exposed rural location but does have the benefit of a mains gas supply.
It its original condition the house would have scored SAP36 in EPC band F and is estimated to have required 515kWh/m2 of gas for heating and hot water, producing 5.3 tonnes CO2.
The current owners have made several energy saving improvements over the last few years including replacing the doors and windows in 2007 with UPVC double glazing. This improvement will have saved around 30kWh/m2.
In 2012, the loft was insulated free under the CESP energy supplier subsidised scheme which provided 250mm of glass fibre insulation and insulation to the loft hatch. This will have further reduced the heating load by around 64kWh/m2.
Later that year, the owners replaced the central heating boiler with a new condensing gas combination boiler fitted in the previous cylinder cupboard. This added a further saving of 163kWh/m2.
Finally, in 2013 the owners agreed to be part of a pilot programme run through the County Council which offered free external wall insulation. The final energy saving has now reached 359kWh/m2 representing a total reduction in the heating and hot water cost of 70%.
This 1940s semi detached house has now achieved an energy efficiency rating of SAP74, similar to a new build property, and with a combined heating and hot water energy cost now expected to be no more than £400 each year. The annual environmental impact of the property has reduced by 66% from 5.3 to 1.6 tonnes CO2.