Calculations The concern about the heat pump is the running costs. Even though the efficiency is 1 to 4 (1kWh in gives 4kWh out), the economics & CO2 savings are somewhat different. My last bill including VAT 1 unit of electricity = 14.58p 1 unity of Gas = 5.17p (see note about split costs below) [...]

Given the current plans what additional insulation is required to reduce the amount of heat that is generated by the heat pump ? Assuming additional insulation is applied, how much electricity will be used to power the heat pump ? This information is an input to the PV requirement Is it possible that heat from [...]