Simon Duffy Getting good advice on making your house more energy efficient is not easy says Simon Duffy When Simon Duffy gets another energy bill, his heart sinks. “It’s madly expensive,” he says. Mr Duffy lives in a traditional stone-walled detached house in Sheffield. He estimates that he spends £3,100 every year on heating and electricity. Despite being someone who cares about climate change, and keen to retrofit his property