See separate comment below for sources. Use the symbols * # ^ to find the relevant source.   This is a comparison of the total forecast lifecycle cost of the heat pump I've just installed, vs the hypothetical gas boiler that I didn't install. This is for my 2-bed end terrace of 71 square meters*. Air to water for heating and hot water. A 50 year old house with cavity wall insulation in one wall and loft insulation.   I have previously discussed this in the separate threa