BusinessGreen: Ground source heat pumps could earn homeowners without access to mains gas up to 3,000 a year in savings and income, according to new research by the Energy Saving Trust (EST). A new paper to be published today provides fresh evidence that ground source heat pumps can generate significant financial and environmental benefits, while also showing that air source heat pumps could generate annual savings and income worth around 1,350. The report shows that with new tariff levels set under the Renewable...