heat_pump_running_cost

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Compare what a household spends heating on its current fuel with what the same heat would cost from a heat pump. The heat demand is worked out from the household's own metered fuel use, not from a model, because a year of bills describes a particular house far better than any estimate of it. Supply the annual fuel use in the fuel's own unit (kWh for gas and electricity, litres for oil and LPG, kilograms for coal), its price per unit in pounds, and the seasonal efficiency of the existing appliance, which defaults to a realistic figure for that fuel instead of the one on the badge. The comparison turns on one ratio. A heat pump costs less to run whenever its seasonal coefficient of performance beats the ratio between the price of a unit of electricity and the price of a unit of heat from the current fuel. The result reports that break-even figure explicitly. SCOP must be the figure at the flow temperature the system is actually designed for. The same machine can return 4.2 at 35 degrees and 3.1 at 55, and quoting the first for a system designed at the second is the commonest way of overstating a saving. This is a running cost comparison. It says nothing about the capital cost or any grant. Method from MCS 007. These calculators follow the published MCS methods, for understanding a system and checking a quotation. Anything that gets installed still needs a design and a site survey from a certified installer.